{"1": {"fulltext": "", "height": "4380", "width": "2888", "jp2-path": "refractionofeye00davi_0001.jp2"}, "2": {"fulltext": "", "height": "4243", "width": "2811", "jp2-path": "refractionofeye00davi_0002.jp2"}, "3": {"fulltext": "1^\\no\\n-^0\\n-u", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0003.jp2"}, "4": {"fulltext": "", "height": "4201", "width": "2698", "jp2-path": "refractionofeye00davi_0004.jp2"}, "5": {"fulltext": "THE REFEACTION OF THE EYE", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0005.jp2"}, "6": {"fulltext": "j3^^", "height": "4201", "width": "2838", "jp2-path": "refractionofeye00davi_0006.jp2"}, "7": {"fulltext": "THE REFRACTION OF THE EYE\\nINCLUDING A COMPLETE\\nTREATISE ON OPHTHALMOMETRY\\nA CLINICAL TEXT-BOOK FOE STUDENTS AND\\nPRACTITIONERS\\nBY\\nA. EDWARD DAVIS, A.M., M.D.\\nAdjunct Professor of Diseases of the Eye in the New York Post-Graduate\\nMedical School and Hospital; Assistant Surgeon to the Manhattan\\nEye and Ear Hospital Attending Ophthalmic Surgeon to the\\nBabies Waixls of the New York Post-Graduate Hospital\\nAttending Ophthalmic Surgeon to Bellevue Hospital,\\nOut-door Department Secretary of the Neio York\\nOphthahnological Society Assistant Secretary\\nof the Neiu York Physicians Mutual Aid\\nAssociation\\nMember of New York State Medical Society, County Medical Society,\\nAcademy of Medicine, etc.\\nWITH ONE HUNDRED AND NINETEEN ENGRAVINGS\\nNINETY-SEVEN OF WHICH ARE ORIGINAL\\nTHE MACMILLAN COMPANY\\nLONDON: MACMILLAN CO., Ltd.\\n1900\\nAll rights reserved", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0007.jp2"}, "8": {"fulltext": "TWO COPIES aECElVEU.\\nOS Of tua\\n\u00c2\u00ab\u00c2\u00bb8l\u00c2\u00abt\u00c2\u00abr of Copyrights\\n51342\\nCopyright, 1900,\\nBy the MACMILLAX COMPANY.\\nSECOND COPY,\\n^c^^.^.\\\\c^^\\nXortoootJ ^ress\\nJ. S. Cushing Co. Berwick Smith.\\nNorwood Mass. U.S.A.", "height": "4245", "width": "2847", "jp2-path": "refractionofeye00davi_0008.jp2"}, "9": {"fulltext": "TO\\nPS M^n\\nH. C. DAVIS, M.D.\\nAND\\nfHg EUn 23rrrtfjer\\nGEORGE E. DAVIS, M.D.\\nTHIS VOLUME\\nIS AFFECTIONATELY DEDICATEI", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0009.jp2"}, "10": {"fulltext": "", "height": "4255", "width": "2837", "jp2-path": "refractionofeye00davi_0010.jp2"}, "11": {"fulltext": "PEEFACE\\nSince the introduction of the perfected ophthalmometer\\ninto ophthalmic practice, rapid strides forward in the art of the\\nrefraction of the eye have been made. With its aid, the prac-\\ntice of fitting glasses quickly and accurately and, as a rule,\\nwithout the aid of any mydriatic whatever has been attained.\\nIt is to the end of demonstrating the clinical and practical\\nuse of the ophthalmometer, and of recording the advances\\nmade in the science and practice of the Refraction of the Eye,\\nthat this book has been written. Some half dozen books on\\nOphthalmoscopy and Retinoscopy have been written, and the\\ntime is opportune for one on Ophthalmometry. We have one\\nsuch book in French, Javal s Memoires d Ophtalmometrie, but\\nnone in English.\\nWhile the present book is intended more especially for\\nbeginners, and for those who have not had the advantage of\\npersonal instruction in the use of the ophthalmometer, it is\\nhoped that its clinical details will interest those in active\\npractice, and who are well versed in the use of the instrument\\nof which it treats. I am especially desirous that it shall be\\nread by a certain rather considerable number of oculists who\\nhave the ophthalmometer in their offices, but who, from the\\nwant of a proper understanding of it, through faulty instruc-\\ntion or a lack of personal instruction, do not use it or, if they.\\ndo know how to use it, do not take into consideration the\\nlimitations of the instrument, and abandon it on tliat account.\\nThrough the citation of a great number of clinical cases,\\ntogether with numerous diagrams illustrating them, I have", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0011.jp2"}, "12": {"fulltext": "viii PREFACE\\ntried to show tlie virtues of the ophthalmometer, while I have\\nnot omitted to note its limitations. In that way, I have hoped\\nto present the instrument in the true light and to justify the\\nclaims made for it.\\nIn composing the book, I have departed from the beaten\\npath, and have devoted the greater part of it to the report\\nin detail of clinical cases illustrating practical points in the use\\nof the ophthalmometer. In other words, instead of a theoreti-\\ncal and didactical discburse, I place a sufficient number of\\ncases themselves (one hundred and fifty in all) before the eye\\nof the reader, which are reported in full, so as to be easily\\nunderstood. To be more explicit still, I may say I have made\\nmy teaching correspond, so far as it is possible in a book, to the\\ninstruction that we give at the Post-Graduate Medical School,\\nwhere the instruction is entirely clinical.\\nI have given an Index of Cases at the close of the book,\\nso that the reader who has a case that he does not fully under-\\nstand, may turn to this index and look for cases in it similar to\\nhis, and then refer to the full report in the body of the book.\\nBy comparison he may get a solution of the case that is puz-\\nzling him. I have done this in order that the student may\\nnot be lost with a case, as is too often true when he refers\\nto the larger text-books wherein no such index is given. It\\nhas been my experience that more can be taught the student\\nby one concrete case illustrating a point in question, than by\\nmany pages of abstract deduction concerning cases which have\\nnever been presented to the student himself.\\nAfter giving a brief description of the instrument and the\\nrules for its use, with some general considerations, I have treated\\nsuccessively, in separate chapters, of its practical use in cases of\\nSimple Hypermetropia and Hj permetropic Astigmatism, Com-\\npound Hypermetropic Astigmatism, Simple Myopia and Myopic\\nAstigmatism, Compound Myopic Astigmatism, and Mixed As-\\ntigmatism, giving many cases and using diagrams to show the", "height": "4260", "width": "2800", "jp2-path": "refractionofeye00davi_0012.jp2"}, "13": {"fulltext": "PREFACE ix\\npoint of focus of the principal meridians, so that the merest\\ntyro must understand them. Incidentally throughout the\\nbook, I have endeavored to show the utter uselessness of a\\nmydriatic in fitting glasses in the vast majority of cases, even\\nin young subjects. If the Ophthalmometer is correctly used\\nand a good routine method followed in putting the glasses in\\nthe trial frames in the subjective test, as here suggested and\\nfully explained, the use of a mydriatic is, with rare exceptions,\\nnever necessary in order to give the right glasses.\\nI desire to express my sincere thanks to Professor St. John\\nRoosa for his kindness in looking over the manuscript, and for\\nmany valuable suggestions both as to the matter and the form\\nof the composition.\\nMr. Fred Stuart has given me much assistance in proof-\\nreading, which I here acknowledge with thanks.\\nMr. Norman P. Findley has made the original drawings\\nfor the book. For the cuts of instruments I am indebted to\\nJVIr. E. B. Meyrowitz and the publishers of the book.\\nA. EDWAED DAVIS.\\nNew York, December, 1899.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0013.jp2"}, "14": {"fulltext": "", "height": "4250", "width": "2837", "jp2-path": "refractionofeye00davi_0014.jp2"}, "15": {"fulltext": "CONTENTS\\nCHAPTER I\\nPAGH\\nHistory of the Ophthalmometer Description of the Instrument 1\\nCHAPTER n\\nPrinciple of the Application of the Ophthalmometer in measuring\\nAstigmatism Rules for its Use Astigmatism with the Rule\\nAstigmatism against the Rule Why the Mires overlap in\\nAstigmatism with the Rule and separate in Astigmatism against\\nthe Rule Why we deduct half a Diopter from the Reading of\\nthe Instrument in Astigmatism with the Rule and add a half\\nDiopter to the Reading when it is against the Rule Rule of\\nProcedure when the Main Meridians are at 45\u00c2\u00b0 and 135\u00c2\u00b0 Prin-\\nciple of the Application of the Ophthalmometer 13\\nCHAPTER III\\nGeneral Considerations in the Use of the Ophthalmometer Simple\\nHypermetropic Astigmatism Simple Hypermetropia Illustra-\\ntive Cases 36\\nCHAPTER IV\\nCompound Hypermetropic Astigmatism Illustrative Cases Spasm\\nof Accomrpodation .80\\nCHAPTER V\\nSimple Myopic Astigmatism Myopia Spasmodic or False Myopia\\nRule for prescribing Near or Reading Glasses in High Degrees\\nof Myopia Presbyopia and the Transposition of Glasses from\\nDistance to Reading in Myopes when it is Present .122\\nxi", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0015.jp2"}, "16": {"fulltext": "xii CONTEXTS\\nCHAPTER YI\\nPAGB\\nCompound Myopic Astigmatism Antimetropia Illustrative Cases\\nAccessory Effects of Strong Myopic Glasses 147\\nCHAPTER Vn\\nMixed Astigmatism Illustrative Cases 175\\nCHAPTER YIII\\nIrregular Astigmatism Conical Cornea Hyperbolic Lenses Con-\\ntact Lenses Illustrative Cases 209\\nCHAPTER IX\\nStrabismus Insufficiencies of the Recti Muscles Amblyopia Illus-\\ntrative Cases 235\\nCHAPTER X\\nAstigmatism after Cataract Extraction Toric Lenses Periscopic\\nLenses Decentering of Lenses Illustrative Cases 309\\nCHAPTER XI\\nExceptional Cases Variations in the Amount and Axis of the Astig-\\nmatism as shown by the Ophthalmometer and as Indicated by the\\nGlasses Accepted by the Patient Illustrative Cases 318\\nAPPENDIX\\nImprovements on the Javal-Schiotz Ophthalmometer: (a) Davis s\\nDouble-movable Mires (b) Talk s Gear-wheel Attachment\\n(c) Skeel s Perpendicular Lever Adjustment (d) Metal Base\\nand other Minor Improvements Reid s Ophthalmometer, a\\nDescription of it and how to use the Instrument Other Oph-\\nthalmometers 383\\nIndex of Cases 411\\nGeneral Index 427", "height": "4247", "width": "2698", "jp2-path": "refractionofeye00davi_0016.jp2"}, "17": {"fulltext": "THE KEFEACTION OF THE EYE", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0017.jp2"}, "18": {"fulltext": "", "height": "4250", "width": "2845", "jp2-path": "refractionofeye00davi_0018.jp2"}, "19": {"fulltext": "CHAPTER I\\nHISTORY OF THE OPHTHALMOMETER DESCRIPTION OF THE\\nINSTRUMENT\\nHistory of the ophthalmometer. The ophthalmometer is\\nan instrument designed to measure the radius of curvature\\nof the cornea in its various meridians. By its use the presence\\nor absence of corneal astigmatism is ascertained; if present,\\nit gives the amount and the axis of the astigmatism.\\nThe instrument was invented by Helmholtz who, as early as\\n185-i, published a description of it together with his conclu-\\nsions as to the exact form of the cornea, as measured by the\\ninstrument.^ Although very accurate in its measurements,\\nthe instrument, as constructed by Helmholtz, was not a prac-\\ntical one. In order to use it the patient was placed six feet in\\nfront of it, and from fifteen to twenty readings made then,\\nbefore the astigmatism was ascertained, mathematical calcula-\\ntions had to be made. As such, it was used in the laboratories\\nof only a few men and for strictly scientific purposes.\\nIt was not until 1880, when Javal and Schiotz made altera-\\ntions and improvements in the instrument, that it became\\npractical for office use, and it was not until 1889 that they\\nperfected the instrument into its present model. As now\\nconstructed, it has about reached the limit of improvement,\\nexcept as to minor details consequently the purchaser is safe\\nin buying it and with the assurance that it will not soon be a\\nback number.\\nDr. Swan M. Burnett, of Washington, was the first Ameri-\\n1 Ueber die Accommodation des Auges, Arch iv fur Ophthalmol, 18-54.\\n1", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0019.jp2"}, "20": {"fulltext": "2 THE REFRACTION OF THE EYE\\ncan to use the Javal ophthalmometer. As earl}^ as 1885 he\\npublished a paper in the Archives of Ophthalmology^ Vol. XIV,\\nFig. 1. The ophthalmometer complete.\\nunder the title of Ophthalmometry with the Ophthalmometer\\nof Javal and Schiotz, with an Account of a Case of Keratoco-", "height": "4261", "width": "2698", "jp2-path": "refractionofeye00davi_0020.jp2"}, "21": {"fulltext": "DESCRIPTION OF THE OPHTHALMOMETER 3\\nnns. Dr. Henry D. Noyes, of New York, began using the\\ninstrument about the same time. Both of these instruments\\nwere old models. In 1887, Dr. Burnett gave a description of\\nthe old model instrument in his Treatise on Astigmatism and\\nin the same year, 1887, in the Reference Hand Booh of the\\nMedical Sciences^ Dr. John Green, of St. Louis, gave a descrip-\\ntion of the instrument with a cut. The instrument remained\\ncomparatively unknown, however, in this country until 1889.\\nWhen the new or 1889 model came out it found among\\nits advocates, among others. Dr. D. B. St. John Roosa, of New\\nYork, who by his earnest and persistent advocacy of the instru-\\nment, especially in the class-room and in the hospital, where\\npractical demonstrations of its use and value were given, did\\nmuch to bring it into general favor. Other writers in America\\nwho have helped to bring the ophthalmometer into esteem are\\nSpeakman, KoUer, Ring, Weiland, Van Fleet, Wurdeman,\\nSwasey, Woodward, Valk, De Schweinitz, Norris, myself, and\\nothers.\\nConstruction of the instrument. To be able to use the\\nophthalmometer well the oculist should at least be somewhat\\nfamiliar with its construction.\\nThe instrument is composed of the following parts\\n1. A telescope on an upright, supported by a tripod.\\n2. A graduated arc, which is the quarter of a circle and\\nattached to the telescope at right angles to it.\\n3. Two mires or reflectors which are attached to the gradu-\\nated arc.\\n4. A large steel disk (Placido s) attached to the telescope,\\njust back of the graduated arc.\\n5. The planchette or base for the instrument to rest on.\\nThe telescope, The telescope is made of brass and has a\\nfixed length. It contains (a) an ocular or eye-piece (0, Fig.\\n2, J.) of .7 inch focus or 56 diopter power double objectives\\n(L and L Fig. 2, A) of 11.2 inch focus each, or about 4 diopter", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0021.jp2"}, "22": {"fulltext": "4 THE REFRACTION OF THE EYE\\npower (c) a cross-thread to show when the eye-piece and\\nobjectives are in adjustment (c[) and a double refracting\\nWallaston prism (W^ Fig. 2, A).\\n(a) The eye-piece can be made to approach or to recede\\nfrom the objectives by means of a small pin which is fixed on\\nthe side of the brass ring that holds the eye-piece, sliding in an\\noblique groove in the side of the telescope. When the cross-\\nthreads in the barrel of the telescope are brought into view by\\nthis means, it shows that the eye-piece is in proper focus with the\\nFig. 2. A, showing vertical sections of the telescope and its component parts.\\nB, horizontal section of the telescope.\\nproximal objective (X Fig. 2, A) and when the distal objective\\n(i. Fig. 2 is brought into exact focus with the eye observed,\\na perfect image of the mires is possible. If the observer is\\nmyopic, he has to push the eye-jDiece inward or to the right to\\nget the cross-threads in focus if he is hypermetropic, the eye-\\npiece has to be pulled outward or to the left to properly focus\\nthem. The eye-piece should always be properly adjusted for\\nthe cross-threads before focussing the instrument on the ob-\\nserved eye. The imported instruments, made by Goubeaux, of\\nParis, have graduations along the oblique slit in which the pin\\non the eye-piece slides. These graduations are so placed that", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0022.jp2"}, "23": {"fulltext": "DESCEIPTIOi^ OF THE OPHTHALMOMETER 5\\neach corresponds to a displacement of the eye-piece to the\\nextent of 1 mm., each millimeter of displacement corresponding\\nto a change in the observer s eye of 3 diopters. For example,\\nwhen the pin on the eye-piece stands at zero an emmetropic\\nobserver should see the cross-threads in the telescope plainly,\\nwhile a myope of 3 diopters would have to turn the pin one\\ngraduation to the right, and a hypermetrope of 3 diopters\\nwould have to turn the pin one graduation to the left in order\\nto see the cross-threads distinctly.\\n(5) The two objectives are exactly alike. Each has a\\ndiameter of 40 mm., or 1.6 inches, and a focal distance of 280\\nmm., or 11.2 inches. They are the most perfect lenses made,\\nbeing both achromatic and aplanatic.\\nThey are so placed in the barrel of the telescope that the\\ncrown of one is turned toward the observed eye, and the crown\\nof the other toward the observer. By this means the flints of\\nthe two objectives are kept opposed and next to the bi-refract-\\ning prism.\\n(a) The cross-threads are two very fine wires stretched at\\nright angles to each other across the barrel of the telescope\\nabout 1 inch in front of the eye-piece and about 11.2 inches\\nbehind the first objective, L They are there simply to show\\nwhen the eye-piece is in proper focus with the objectives.\\n(d) The hi-refracting prism (Wallaston) placed between the\\ntwo objectives is in fact two prisms, placed apex to base and\\nbase to apex. In this country, at least in the instruments man-\\nufactured by Meyrowitz and Georgen, these prisms are made\\nfrom the best mountain crystal quartz. They possess the power\\nof doubling objects, that is, are bi-refractive, if ground in a\\ncertain direction with regard to the axis of the quartz. The\\namount of the deviation or doubling produced by each prism\\ndepends on the angle at which it is ground.\\nOne of the prisms is ground diagonally with the grain of\\nthe quartz (a. Fig. 3), while the other is ground at right angles", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0023.jp2"}, "24": {"fulltext": "THE REFRACTIOX OF THE EYE\\nFig. 3. Thebi-re-\\nto it Fig. 3); see cut, looking down on them from above as\\nthey are placed in the telescope of the instrument. Thus placed,\\ntheir axes are at right angles to each other and at the same time\\ntransverse to the axis of the telescope. Each\\nprism when ground at a certain angle causes a\\ndefinite amount of deviation; and by using two\\nprisms, apex to base and base to apex, the de-\\nviation takes place from each side, thus getting\\ntwofold the deviation that would be caused by\\none prism and at the same time keeping the\\ndoubled images nearer the center of the field.\\nFurthermore, these prisms are placed in the\\nfractive prism telescope with their plane of doubling in ex-\\nas placed in the\\ntelescope. With the plane ot the graduated arc,\\nwhich latter is fixed to the telescope of the\\ninstrument at right angles to it by two screws in a brass\\ncollar.\\nIt is very important, therefore, that these two screws should\\nnot be meddled with; for, if moved in the least, the arc and\\nthe plane of the prism is altered, and the instrument cannot be\\nused again until readjusted by an expert.\\nThe prisms in Javal s instrument produce a deviation of 2.95\\nmm. when the instrument is focussed on an object at double the\\nfocal distance of the objective, or 460 mm. When, therefore,\\nthe instrument is properly focussed on the cornea, the latter is\\ndoubled by the prism, and each point of the image reflected\\nfrom the cornea is displaced to the extent of 2.95 mm. Con-\\nsequentlj^ if the image of the object reflected from the cornea\\nhappened to be just 2.95 mm. in length, the de^dation of 2.95\\nmm. caused by the prism would allow the edges of the doubled\\nimage to just touch, as in Fig. 4.\\nSay the image of the arrow 1-2 is just 2.95 mm. in length,\\nand by the deviation caused by the prism each of its points are\\ndisplaced correspondingly the distance of 2.95 mm. then the", "height": "4264", "width": "2698", "jp2-path": "refractionofeye00davi_0024.jp2"}, "25": {"fulltext": "DESCRIPTION OF THE OPHTHALMOMETER 7\\ntail of the secondary image, V-2 will just touch the head of\\nthe primary image, 1-2.\\nIn this way we are enabled to measure the size of the cor-\\nneal image by the amount of displacement it is necessary to\\n2.95 MM. 2.95 MM\\n1 2 1 2\\nFig. 4. Showing the exteut of displacement in the Javal-Schiutz instrument.\\ngive to each point of the image in order to have the edges\\nof the doubled images just touch.\\nInstead of an arrow, Javal takes for his object the distance\\nbetween the inner edges of two mires or reflectors, 1 and 2,\\nFig. 7. Here, as in the case of the arrow, the prism, from its\\nfixed position in the telescope, causes a deviation of 2.95 mm.\\nConsequently, if the two mires are so arranged on the arc of\\nthe instrument that, by this deviation of 2.95 mm., the inner\\nedges of the images of the two mires are just touching, it is\\nquite plain that the diameter of this image must be just 2.95 mm.\\nFurthermore, it is equally plain that the distance between the\\ninner edges of the two mires, in this instance, is equal to the\\nsize of the object, in fact, is the object which gives a reflected\\nimage 2.95 mm. in diameter.\\nThe bi-refracting prism in the Javal-Schiotz instrument\\ncauses a fixed deviation of 2.95 mm.,^ the arc on which the\\nmires move has graduations to show the distance apart of\\nthe two mires, and thereby the size of the object; and twice the\\nfocal distance of the objective determines the distance of the\\nobject from the cornea. With these three points known it is\\neasy to find the fourth, the radius of curvature of the cornea\\n1 An extra tube with a prism causins; less deviation and therefore a smaller\\nimage is furnished with the instrument which is of use in cases of marked varia-\\ntion from the average radius of curvature of the cornea.\\nI\\nI", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0025.jp2"}, "26": {"fulltext": "8 THE REFRACTION OF THE EYE\\nin its various meridians, and thereby ascertain the presence or\\nabsence of astigmatism the object of the ophthalmometer.\\nThe graduated arc is an arc with a radius of its inner edge\\nof 290 mm. When focussed on the observed eye it is concentric\\nwith the cornea. The posterior edge of the arc is graduated\\ninto equal spaces and numbered, the numbering beginning at\\nthe center and extending in each direction to 40 spaces. Each\\none of the divisions on the posterior edge of the arc, taken in\\nconnection with the doubling of the image by the prism, stands\\nfor a diopter mark. For example, if, with an eye under observa-\\ntion and the arc in the horizontal meridian, the images of the\\nmires just touch when the mires on each side of the arc stand\\nat the 20 mark, it shows that the refractive power of the hori-\\nzontal meridian of the cornea is 40 diopters. If now we turn\\nthe arc to the vertical meridian of the cornea and the images of\\nthe mires overlap, say three steps, it shows 3 diopters of astig-\\nmatism, which may be verified by the graduations on the poste-\\nrior edge of the arc in the following way. While still looking\\nat the images through the telescope as they appear overlapped\\nthere, move the graduated mire outward along the arc till the\\nimages are left just touching again. Then by looking at the\\nposterior edge of the arc we will find that the graduated mire\\nhas moved the distance of just three graduations thus veri-\\nfying the amount of astigmatism present and at the same time\\nshowing the vertical meridian of the cornea to have a refractive\\npower of 43 diopters.\\nOn the right side of the arc on its inner edge are some\\nfine graduations and some figures. On the instrument\\nwith the single movable mire these figures go from 6 mm.\\nto 10 mm. on the instruments with double movable mires\\n(improved) from 5 mm. to 13 mm. By noting the position\\nof the graduated mire on the right side of the arc in relation\\nto these graduations when the images of the two reflectors just\\ntouch, in any meridian whatever, the number corresponding", "height": "4260", "width": "2698", "jp2-path": "refractionofeye00davi_0026.jp2"}, "27": {"fulltext": "DESCRIPTION OF THE OPHTHALMOMETER 9\\nindicates the radius of curvature of the cornea in that particu-\\nlar meridian in millimeters. These figures are very important,\\ntherefore, and should be noted carefully, for by them we are able\\nto register the radius of curvature of the cornea in millimeters\\nin its various meridians.\\nTwo mires or reflectors are attached to the arc. One of\\nthem is a parallelogram, 60 mm. long by 30 mm. wide, and, in\\nthe unimproved instrument, is fixed at 20 on the left-hand side\\nof the arc. The other is a graduated mire, each graduation or\\nstep is 10 mm. long by 5 mm. broad, and counts as 1 diopter.\\nThere are eight of these steps.\\nDividing the mires into halves are two narrow black lines,\\ncalled guide-lines. The lines are parallel with the planes of\\nthe arc. They serve to show when the arc is in one of the\\nchief meridians of curvature of the cornea, that is, when it\\nis in the meridian of longest radius of curvature, or in the\\nmeridian of the shortest radius of curvature.\\nThey do this by showing perfectly straight and\\nopposite each other when the arc is turned to\\neither of the chief meridians of curvature (see\\nFig. 5), but run obliquely toward each other in\\nall other meridians (see Fig. 6). Of course where there is no\\ncorneal astigmatism, the cornea being uniformly and evenl}^\\ncurved, they will remain straight and opposite\\neach other in all meridians. As we have to find\\none of the chief meridians of the cornea, that\\nis, get the primary position or starting point\\nin measuring corneal astigmatism, these lines are\\nof much importance. A small pointer or indicator is attached\\nto the outer side of each mire, which points to figures on the\\nperiphery of a large disk, where the axis of the meridian is\\nmarked in degrees of a circle. These short indicators on the\\nreflectors serve as a check to a long indicator which is attached\\nto the middle of the graduated arc and at right angles to it.\\nFig. 5.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0027.jp2"}, "28": {"fulltext": "10 THE REFRACTION OF THE EYE\\nThis long indicator shows the direction the arc is in when the\\nlong black lines dividing the reflectors become straight with\\neach other. For example, say the black lines dividing the mires\\nbecome straight when the arc is in the horizontal meridian of a\\ncornea having astigmatism with the rule. The long indicator,\\nsince it is at right angles to the arc, wdll be pointing directly\\ndownward (directly upward, however, as seen in the telescope,\\nbecause the image is an inverted one) to 0\u00c2\u00b0, which is the same\\nas regards axis as 180\u00c2\u00b0, for 180\u00c2\u00b0 just completes the half of a\\ncircle.\\nIt will be noticed that 0\u00c2\u00b0 or 180\u00c2\u00b0 is marked on the big disk\\ndirectly above and directly below, and does not occupy the\\nhorizontal meridian, as is usually the case. This is due to the\\nfact that the long indicator is at right angles to the arc whose\\ndirection it indicates. Therefore, when the arc is really in the\\nhorizontal meridian (0\u00c2\u00b0 or 180\u00c2\u00b0) the long indicator is in the\\nvertical meridian, consequently the 0\u00c2\u00b0 has to be put there.\\nThis explains why 0\u00c2\u00b0 is marked in the vertical meridian and\\n90\u00c2\u00b0 in the horizontal meridian on the disk.\\nWhen the long indicator points to 0\u00c2\u00b0 the short indicator\\nshould point exactly to 90\u00c2\u00b0 in this way the latter serves as\\na check to the long indicator, as above stated.\\nThe disk (Placido s) is a large circular sheet of steel 640\\nmm. (25.6 inches) in diameter attached to the telescope at\\nright angles to it and just back of the graduated arc. Upon\\nthis disk are concentric white circles on a black background,\\nalso radiating lines extending from its center. The concentric\\nwhite circles are five degrees apart, numbering from the center\\nto the periphery a distance of 45\u00c2\u00b0. They are constructed on\\nthe law of tangents, that is, the radius of each circle represents\\nthe tangent of an arc drawn from the center of the graduated\\narc.\\nThe circles marked 15\u00c2\u00b0 and 30\u00c2\u00b0 are broader than the others,\\nand on the 30\u00c2\u00b0 circle beginning above, the radiating lines from", "height": "4265", "width": "2841", "jp2-path": "refractionofeye00davi_0028.jp2"}, "29": {"fulltext": "descriptio:n^ of the ophthalmometer 11\\nthe center of the disk are numbered in the degrees of a circle\\nfrom 0\u00c2\u00b0 to 360\u00c2\u00b0 a complete circle (see Fig. 1). By number-\\ning both the concentric circles and the radiating lin-es in this\\nmanner, this disk can be used as a perimeter for the same\\nreason it can be used to make observations on the cornea out-\\nside of the visual line.\\nAt the periphery of the disk, between the 40\u00c2\u00b0 and the 45\u00c2\u00b0\\ncircles, is a large white border. On this white border are\\nlarge inverted figures 15\u00c2\u00b0 apart. Instead of numbering\\nfrom 0\u00c2\u00b0 to 360\u00c2\u00b0, as did the small figures on the 30\u00c2\u00b0 circle,\\nthey stop at 180\u00c2\u00b0, then begin again and number up to 180\u00c2\u00b0\\nor 0\u00c2\u00b0, where they first began (see Fig. 1). These figures\\nappear upright or straight when viewed as a reflected image\\nfrom the cornea, for this image is inverted.\\nOn the right side of the disk in the horizontal meridian the\\nnumbers 3 mm., 4 mm., and 5 mm. appear. These are meant\\nto aid in measuring the diameter of the pupil. In order to do\\nso, however, an extra strong objective has to be put in the\\ntelescope, and an extra brilliant illumination obtained. If the\\npupil seems to extend out to the circle marked 3 mm., it is\\n3 mm. wide, etc.\\nOn the opposite side of the disk are seen the figures 35, 40,\\n45, and 50. When viewed in the corneal image, if any one\\nof these circles so numbered become tangent to itself (through\\nthe doubling caused by the prism), the figures denote the powder\\nof refraction, or dioptric power, of the cornea in that meridian.\\nFor example, say the circle marked 40 becomes tangent to\\nitself thus 00 in the horizontal meridian the refractive\\npower of the cornea in that meridian would be 40 diopters.\\nThe reason that the numbering at the periphery of the disk\\nbegins at 0\u00c2\u00b0 and goes to 180\u00c2\u00b0, then repeats itself from 0\u00c2\u00b0 to\\n180\u00c2\u00b0 again instead of completing the circle of 360\u00c2\u00b0 (as in the\\n30\u00c2\u00b0 circle in small figures), is that both ends of any corneal\\nmeridian under measurement may be indicated by the same", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0029.jp2"}, "30": {"fulltext": "12 THE REFRACTION OF THE EYE\\nnumber on each side of tlie disk. For this reason each mire\\nhas a short pointer on it. These pointers not only point to\\nthe same number of degrees on each side of the disk, but serve\\nas a check at the same time on the long pointer or indicator.\\nFor example, when the short pointers each point to 0\u00c2\u00b0, the long\\npointer should be exactly at 90\u00c2\u00b0, at right angles. Again, by\\nmeans of these short pointers and the double numbers on the\\ndisk, the angles of the chief meridians can be seen at once from\\nthe reflected image. This is one strong reason why this big\\ndisk should not be removed from the instrument and replaced\\nby a smaller black velvet disk and upright numbering on a\\nsmall medal disk facing the observer, as is now sometimes done\\nby some Americans.\\nFor a description of the improvements made on the Javal-\\nSchiotz instrument and modifications of it, and for descriptions\\nof other ophthalmometers, see Appendix.", "height": "4259", "width": "2819", "jp2-path": "refractionofeye00davi_0030.jp2"}, "31": {"fulltext": "CHAPTER II\\nPRINCIPLE OF THE APPLICATION OF THE OPHTHALMOMETER IN\\nMEASURING ASTIGMATISM RULES FOR ITS USE ASTIGMA-\\nTISM WITH THE RULE ASTIGMATISM AGAINST THE\\nRULE WHY THE MIRES OVERLAP IN ASTIGMATISM WITH\\nTHE RULE AND SEPARATE IN ASTIGMATISM AGAINST THE\\nRULE WHY WE DEDUCT HALF A DIOPTER FROM THE READ-\\nING OF THE INSTRUMENT IN ASTIGMATISM WITH THE RULE,\\nAND ADD A HALF DIOPTER TO THE READING WHEN IT IS\\nAGAINST THE RULE RULE OF PROCEDURE WHEN THE MAIN\\nMERIDIANS ARE AT 45\u00c2\u00b0 AND 135\u00c2\u00b0 PRINCIPLE OF THE APPLI-\\nCATION OF THE OPHTHALMOMETER\\nThe principle on which the ophthalmometer acts in meas-\\nuring the radius of curvature of the cornea in its various\\nmeridians, and thereby marking the corneal astigmatism, con-\\nsists simply in the measurement of the size of a small image\\nreflected on the cornea.\\nIn order to measure this image the more easily, it is first\\ndoubled by the bi-refracting prism in the telescope of the\\ninstrument. The objects furnishing this image are the inner\\nedges of the two mires. The images of both the mires, as\\nwell as that of the disk, are doubled by the prism, so that, as\\nviewed through the telescope, we have four mires and two\\ndisks (see Fig. 7). 1 and 1 are the images of the graduated\\nmire, and 2 and 2 are the images of the rectangular mire.\\nIn practice, however, we pay no attention to the two outer\\nimages, 1 and 2,^ but notice simply the two inner images. 1\\nand 2, in the oval space made by the overlapping of the double\\nimages of the disk (see Fig. 7). The distance, a a between\\nthe inner edges of the images of the rectangular mire, denoted\\n13\\nI\\nI", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0031.jp2"}, "32": {"fulltext": "14\\nTHE REFRACTION OF THE EYE\\nby the dotted line in Fig. 7, and h h\\\\ the distance between the\\ninner edges of the images of the graduated mire, each repre-\\nsents the amount of deviation caused by the prism, which is\\n2.95 mm. Now as a a is tlie image of the object under meas-\\nFiG. 7.\\nA, diagram of the mires alone. B, reflection of the whole instrument from\\nthe front of the cornea, with the arc at 180\u00c2\u00b0.\\nurement, that is, the distance between the inner edges of the\\ntwo mires, we know its size to be just 2.95 mm. in this\\ninstance. Take a case in actual practice. For example, when\\nthe instrument is focussed properly on an eye, the black lines\\ndividing the mires become coincident with each other in the", "height": "4263", "width": "2698", "jp2-path": "refractionofeye00davi_0032.jp2"}, "33": {"fulltext": "USE OF THE OPHTHALMOMETER\\n15\\nhorizontal meridian (c d, Fig. 7). This shows that one of the\\nchief meridians of curvature of the cornea is the horizontal\\nmeridian. Approximate the images till they just touch, then\\nturn the arc at right angles to the horizontal meridiaUo If\\nthere is no overlapping or separation of the images V and 2, it\\nshows that the vertical meridian of the cornea has the same\\nradius of curvature as the horizontal. If the vertical meridian\\nFig. 8. The same images as in Fig. 7, but with the arc at 90\u00c2\u00b0.\\nhas a shorter radius of curvature, the images will overlap to a\\ncertain extent, say, two steps (see Fig. 8).\\nThis must necessarily be so, for the size of the ohject (the\\ndistance between the inner edges of the mires as placed on the\\narc) and the distance of this object from the cornea havino-\\nremained the same, we must obtain a smaller image on a sur-\\nface with a shorter radius of curvature. The distance between\\n1 and 1 and 2 and 2 remaining the same from the constant\\ndeviation caused by the prism, the reduction in the size of the", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0033.jp2"}, "34": {"fulltext": "16 THE REFRACTION OF THE EYE\\ncorneal image cannot take place in a change of length of these\\nlines. It must be brought about, therefore, by an overlapping\\nof the inner edges of the images 1 and 2 (Fig. 8). The num-\\nber of steps overlapped shows the amount of astigmatism, and\\nthe direction of the long and short indicators respectively shows\\nthe axis at which plus or minus glasses will be worn, in any\\ncase whatever.\\nRULES FOR ITS USE\\nThese rules for the use of the ophthalmometer are taken in\\nthe main from articles on this subject by myself They are\\nintended to be so simple, plain, and direct, that even the very\\nbeginner should be able to use the instrument by their guid-\\nance. Of course, personal instruction is always preferable to\\nwritten, and, where it is possible, I would advise several les-\\nsons by some one skilled in the use of the instrument.\\n1. Have a perfect light. The light from a large north\\nwindow four 16-candle-power electric lamps or two Welsbach\\ngas burners with suitable reflectors, are all good illuminants.\\n2. See that the telescope, or tube, of the instrument is cor-\\nrectly adjusted, by sighting through it, and bring the cross-\\nwires in good view. This is done by turning the ocular, or\\neye-piece, to the right when the observer is myopic, and to tlie\\nleft when he is hypermetropic. The further to the left that the\\neye-piece can be turned, and yet the cross-wires be maintained\\nin good view, the better and for the same reason which we\\nfollow in prescribing glasses the weaker the minus and the\\nstronger the plus glass the better, because by this means no\\nextra accommodation is called into play.\\n3. Place the patient at the instrument with his chin on the\\nchin-rest and his forehead against the forehead-rest, with his\\neyes wide open and upon a level. To know when the eyes are\\nexactly horizontal, which is all important, sight through the\\n1 New York Medical Journal, September 10, 1892, October 8, 1892.", "height": "4256", "width": "2698", "jp2-path": "refractionofeye00davi_0034.jp2"}, "35": {"fulltext": "RULES FOE, ITS USE 17\\ntransverse slit in the disk just above the tube, or telescope, of\\nthe instrument. This point cannot be insisted upon too much,\\nfor the least rotation of the head will throw the axis off 5\u00c2\u00b0 or\\n10\u00c2\u00b0 from what it really is, and then, when we come to the trial\\ncase, and the axes do not correspond, we are prone to blame the\\ninstrument when we are ourselves at fault.\\n4. The eyes level, we are now ready to place the blind in\\nfront of one eye and focus the other. To focus the eye, sight\\nalong the upper side of the tube through the notch (something\\nlike a gun sight) at the center of the cornea. Now sight\\nthrough the tube, at the same time moving the instrument for-\\nward and backward on the planchette, and u;^ and down by\\nmeans of the screw, until the image of the disk, doubled by the\\nprism in the telescope, and reflected from the cornea inverted,\\ncomes into view. Pay no attention to the two reflectors far out\\nat the sides, but notice the two reflectors in the oval space\\nmade by the overlapping of the disks.\\n5. Obtain the primary position. The primary position\\nis nothing more or less than that point at which the transverse\\nlines, dividing the reflectors into halves, become opposite, or\\ncoincident, and form one continuous straight line, which is an\\nindication simply (when there is any astigmatism) that we have\\nfound one of the axes of the astigmatism. The other axis, in\\nthe great majority of cases, is 90\u00c2\u00b0 from this, therefore at right\\nangles to it, and is the secondary position. When there is\\nno astigmatism, the transverse lines are always opposite and\\ncoincident. When there is irregular astigmatism, they are\\nnever coincident. To obtain the primary position, first turn\\nthe long indicator to 0\u00c2\u00b0. If the transverse lines are coincident\\nat this point, go no further tliat is the primary position. If\\nnot coincident at the zero point, turn the tube from right to\\nleft that is, the long indicator from 0\u00c2\u00b0 to 135\u00c2\u00b0. If the trans-\\nverse lines do not become coincident before or when 135\u00c2\u00b0 is\\nreached, go no farther in that direction, but turn back to 0\u00c2\u00b0,", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0035.jp2"}, "36": {"fulltext": "18 THE REFRACTION OF THE EYE\\nturning this time from left to right, toward 45\u00c2\u00b0 the lines will,\\nnecessarily, become coincident before 45\u00c2\u00b0 is reached. The\\nprimary position is never farther than 45\u00c2\u00b0 on either side of 0\u00c2\u00b0.\\nThis I wish especially to emphasize, for if we turn farther than\\nthe 135\u00c2\u00b0 mark on one side or the 45\u00c2\u00b0 on the other, we will make\\nthe astigmatism with the rule, when it is really against the\\nrule, and vice versa. When the lines become coincident at\\n135\u00c2\u00b0 or 45\u00c2\u00b0, the extreme limits, being just halfway between 0\u00c2\u00b0\\nand 90\u00c2\u00b0 on either side, by preference take 135\u00c2\u00b0 as the primary\\nposition this for the sake of nomenclature. We see then\\nthat the primary position may he at 0\u00c2\u00b0 or any point within\\n45\u00c2\u00b0 of that point, but never beyond. Having got the lines\\ncoincident, it is only necessary to approximate the reflectors to\\nbe ready for the next step.\\n6. That of obtaining the second position. This is ob-\\ntained by turning the long indicator 90\u00c2\u00b0 to the left from the\\nprimary position. If the reflectors overlap, there is astigma-\\ntism with the rule, and the number of steps of overlapping is\\nthe amount of the astigmatism. Say it overlaps two steps. It\\nshould be written thus Astigmatism with the rule, 2 D.\\n90\u00c2\u00b0 or 180\u00c2\u00b0 If the reflectors separate when the second\\nposition is reached, it indicates astigmatism against the rule.\\nBefore moving the indicator from the second position, approxi-\\nmate the reflectors again, and then turn back to the primary\\nposition, when the plates Avill overlap say two steps, written\\nthus Astigmatism against the rule, 2 D. 180\u00c2\u00b0+ or 90\u00c2\u00b0-.\\nFollowing the rules above, the long indicator always points the\\naxis the plus glass will be worn, and the short indicator on\\nthe reflectors the axis the minus glass will be w^orn in any\\ncase. It may be asked why I prefer to turn the cylinder from\\nright to left. Simply that I may have the sliding indicator\\nbelow, where I can get at it through the holes in the disk below.\\nOf course the observer s eye should be properly corrected if\\nhe has any error of refraction.", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0036.jp2"}, "37": {"fulltext": "ASTIGMATISM WITH THE RULE 19\\nNow, what does the instrument do It gives the amount\\nof the astigmatism and the axis. These points ascertained,\\nthe rest is easy.\\nAs to the amount of the astigmatism as indicated by the\\nophthalmometer and that accepted by the patient, we need\\nnever be in doubt as to the proper glass to prescribe if we will\\nonly follow what Javal has taught us, that in astigmatism\\nwith the rule that is, the vertical axis of the cornea being\\nthe more curved, let the astigmatism be hypermetropic, myopic,\\nmixed, simple, or compound we have only to subtract one-\\nhalf to three-quarters of a diopter from that indicated by the\\ninstrument to have the proper glass and in astigmatism\\nagainst the rule, the horizontal meridian of the cornea being\\nthe more curved, let the astigmatism be hypermetropic, myopic,\\nmixed, simple, or compound, to give full correction we add\\nhalf a diopter to that indicated by the instrument. The ex-\\nceptions to this rule are rare, the variation of half a diopter\\ntoo much with, and half a diopter too little against, the rule\\nbeing a fairly constant one and one to be expected, in the\\ngreat majority of cases. Of course the readings of the instru-\\nment should be verified by the ophthalmoscope and trial case\\nbefore glasses are prescribed.\\nAstigmatism with the rule,^ There has been so much\\nconfusion in the minds of beginners, and I may say also even\\nin the minds of men of considerable experience, about astig-\\nmatism with the rule and astigmatism against the rule\\nthat very explicit and short definitions of each will not be out\\nof place here. Where the vertical meridian of the cornea, or any\\nmeridian in the neighborhood of the vertical meridian, that is,\\nwithin 45\u00c2\u00b0 of the vertical, is more curved than the meridian at\\nright angles to it, that condition is called astiginatism with\\nthe rule.\\nThis is all there is to astigmatism with the rule it simply\\nmeans that the vertical meridian of the cornea, or one near it,", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0037.jp2"}, "38": {"fulltext": "20 THE REFRACTION OF THE EYE\\nis more curved than the meridian at right angles to it. And\\nsince the vertical meridian, or one in the neighborhood of it, is,\\nas a rule (perhaps in 75 to 80 per cent of all cases of astigma-\\ntism), more curved than the horizontal, or the meridian at right\\nangles to it, the astigmatism in such cases is said to be accord-\\ning to the rule, or with the rule. French writers often call\\nthis direct astigmatism, while they designate astigmatism\\nagainst the rule as indirect astigmatism.\\nMany times beginners ask if hypermetropic astigmatism is\\nnot always with the rule, and if myopic astigmatism is not\\nalways against the rule. As a matter of fact, it makes no dif-\\nference whether the astigmatism be hypermetropic (simple or\\ncompound), myopic (simple or compound), or even mixed, just\\nso the vertical meridian of the cornea or one within 45\u00c2\u00b0 of it is\\nmore curved than the meridian at right angles to it, that is\\nastigmatism with the rule.\\nIn order that the reader cannot possibly go astray on this\\npoint, I will take an example of each form of astigmatism, and\\nshow by diagrams how it may be with the rule in every f orm.^\\nFig. 9.\\n1 Under the heading of astigmatism against the rule, I show how astigmatism\\nmay he against the rule in all its forms.", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0038.jp2"}, "39": {"fulltext": "ASTIGMATISM WITH THE RULE\\n21\\n1. Simple hypermetropic astigmatism, with the rule. Figure\\nNo. 9 shows the vertical and horizontal sections of an eye with\\nsuch an error of refraction. It is seen by this diagram that the\\nvertical meridian is emmetropic and allows the rays of light to\\nfocus on the retina, and is more curved than the horizontal\\nmeridian which is flat and allows the rays of light to focus back\\nof the retina. Therefore, according to our definition of astig-\\nmatism with the rule, this must be a case of it, for the vertical\\nmeridian is more curved than the horizontal.\\n2. Compound hypermetropic astigmatism with the rule. In\\nsuch a case the vertical meridian is flat and allows the rays of\\nFig. 10.\\nlight to focus back of the retina, but it is not as flat as the\\nhorizontal meridian which allows the rays to focus still farther\\nbehind the retina. Here again the vertical meridian is more\\ncurved than the horizontal, and, of course, the astigmatism is\\nwith the rule, though it is compound hypermetropic.\\n3. Simple myopic astigmatism with the rule. Here the ver-\\ntical meridian is myopic, causing the rays of light to focus in\\nfront of the retina, and is more curved than the horizontal\\nmeridian which is emmetropic, and allows the rays to focus on", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0039.jp2"}, "40": {"fulltext": "22\\nTHE REFRACTIOX OF THE EYE\\nthe retina. ISTow, this is with the rule, though it is myopic\\nastigmatism simply because the vertical meridian is the more\\ncurved.\\nFig. 11.\\n4. Compound myopic astigmatism ivith the rule. The verti-\\ncal meridian is more myopic and at the same time more curved\\nVERT. MERID,\\nFig. 12.\\nthan the horizontal meridian, which latter fact makes it astig-\\nmatism with the rule.", "height": "4257", "width": "2698", "jp2-path": "refractionofeye00davi_0040.jp2"}, "41": {"fulltext": "ASTIGMATISM AGAINST THE RULE\\n23\\n5. Mixed astigmatism with the rule. The vertical meridian\\nis myopic and focusses rays of light in front of the retina, and\\nis more curved than the horizontal meridian which is hyper-\\nmetropic (fiat, less curved), and focusses rays back of the retina.\\nThe astigmatism is with the rule, therefore, though mixed.\\nFig. 13.\\nWe see, then, by the above five diagrams that astigmatism\\nmay be with the rule in all of its forms the only thing neces-\\nsary to have it such, the sine qua non, so to speak, is that the\\nvertical meridian of the cornea or one in its neighborhood shall he\\nmore curved than the horizontal or the one at right angles to it.\\nWhere the vertical meridian of the cornea, or any meridian\\nin the neighborhood of the vertical meridian, that is, within\\n45\u00c2\u00b0 of the vertical, is less curved than the meridian at right\\nangles to it, that is astigmatism against the 7^ule.\\nIn other words, astigmatism against the rule means simply\\nthat the vertical meridian of the cornea is less curved than\\nthe horizontal and this condition may obtain in any form\\nof astigmatism hypermetropic (simple or compound), myopic\\n(simple or compound), and in mixed astigmatism, as the fol-\\nlowing diagrams show\\n4\\nI", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0041.jp2"}, "42": {"fulltext": "24\\nTHE refractio:n^ of the eye\\n1. Simple hypermetropic astigmatism against the rule.\\nThe vertical meridian is hypermetropic, focusses rays of light\\nback of the retina, and is less curved than the horizontal\\nmeridian, which is emmetropic, and focusses rays on the retina.\\nFig. 14.\\n2. Compound hypermetropic astigmatism against the rule.\\nHere both meridians are hypermetropic, but the vertical more\\nso than the horizontal, consequently the vertical meridian is\\nFig. 15.", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0042.jp2"}, "43": {"fulltext": "ASTIGMATISM AGAINST THE RULE\\n25\\nless curved than the horizontal. The astigmatism is, therefore,\\nagainst the rule.\\n3. Simple myopic astigmatism against the rule. The ver-\\ntical meridian is emmetropic, focusses the rays on the retina,\\nFig. 16.\\nand is less curved than the horizontal meridian, which is\\nmyopic, and focusses rays in front of the retina.\\n4. Compound myopic astigmatism against the rule. Here\\nboth meridians are myopic, but the vertical is less myopic than\\nFig. 17.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0043.jp2"}, "44": {"fulltext": "26\\nTHE REFRACTION OF THE EYE\\nthe horizontal, is less curved, and consequently it is astig-\\nmatism against the rule.\\n5. Mixed astigmatism against the rule. The vertical me-\\nridian is hypermetropic, focusses rays back of the retina, and\\nis less curved than the horizontal meridian, which is myopic,\\nand focusses rays in front of the retina.\\nFig. 18.\\nBy the above diagrams we see that astigmatism may be\\nagainst the rule in all its forms. So long as the vertical me-\\nridian of the cornea is less curved than the horizontal, that is\\nastigmatism against the rule.\\nI have gone very particularly and minutely into this point\\nof astigmatism with the rule and astigmatism against the rule,\\nbecause I have found in my teaching at the Post- Graduate\\nSchool of Medicine that it is a point on which most beginners\\nare in doubt. I may add that I have seen many others who\\nhave used the instrument for a long time not clear on the\\nquestion. Some authors are inclined to give but little impor-\\ntance to it, but I have found it of much value in instructing.\\nBecause, if, on finding the astigmatism with or against the\\nrule with the ophthalmometer, you can teach the student to", "height": "4259", "width": "2784", "jp2-path": "refractionofeye00davi_0044.jp2"}, "45": {"fulltext": "WHY THE MIRES OVERLAP AND SEPARATE 27\\npicture in his mind s eye, so to speak, the condition of cur-\\nvature of the cornea and the position of the focal points of its\\ntwo chief meridians of curvature in relation to the retina in\\nthe various forms of astigmatism, it greatly assists him in\\nadjusting glasses. In fact, it makes him think of the eye under\\nobservation, and not of some abstruse rule in a text-book.\\nWhy the mires overlap in astigmatism with the rule; why\\nthey separate in astigmatism against the rule. It is a well-\\nknown fact to those who have used the ophthalmometer, that\\nin astigmatism with the rule, the images of the mires overlap\\nwhen turned from the primary to the secondary position and\\nthat these same images in astigmatism against the rule separate\\nwhen turned from the primary to the\\nsecondary position. Why is this so?\\nFigure 19 shows the general form of\\nthe cornea, front view, in astigmatism with\\nthe rule.\\n,-_^ .,1 Fig. 19. Showing front\\nW e Will assume a case with the two view of an eye with\\nchief meridians of curvature at 90\u00c2\u00b0 and astigmatism with the\\nrule.\\n180\u00c2\u00b0, exactly.\\nIn such a case the primary position would be found\\n(rule 5, p. 17) at 180\u00c2\u00b0. If the inner edges of the images\\nare then approximated and the arc turned 90\u00c2\u00b0 to the second-\\nary position, the doubled images of the object under measure-\\nment cannot become smaller from side to side (the deviation\\ncaused by the prism remaining the same), except by overlap-\\nping at their inner edges, which they do (see Fig. 8). And\\nthe greater the difference in curvature of the two chief merid-\\n1 In passing, it may be said that the primary position is nothing more\\nthan the starting point, or the first position in wliicli the lines dividing the mires\\ninto halves become straight with each other, showing that one of the two chief\\nmeridians of curvature of the cornea has been found. Hence it is called the\\nprimary or first position. The secondary position is at right angles to\\nthe primary and is called secondary simply because it is the second posi-\\ntion reached.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0045.jp2"}, "46": {"fulltext": "28\\nTHE REFRACTION OF THE EYE\\n180\\nFig. 20. Diagram of\\nfront view of an\\neye with astigma-\\ntism against the\\nrule showing a ver-\\ntical oval.\\niaus the more overlapping there will be in astigmatism with the\\nrule.\\nIn astigmatism against the rule, just the reverse holds, that\\nis, the images separate when turned from the primary to the\\nsecondary position. A glance at Fig. 20,\\nwhich represents the general form of the\\ncornea, front view, in astigmatism against\\nthe rule, easily explains this.\\nHere the doubled images of the mires\\nare approximated on a meridian with a\\nshorter radius of curvature than the verti-\\ncal meridian. Consequently, when the im-\\nages are turned to the secondary position,\\n90\u00c2\u00b0 in this instance, to a meridian with a\\nlonger radius of curvature, the images must\\nbecome larger. But since the deviation caused by the prism\\nis a constant one (2.95 mm.), the doubled images cannot\\nbecome larger from side to side, except by pulling apart or\\nseparating at their inner edges, which they do.\\nThe greater the difference in the radius of curvature of the\\ntwo chief meridians the greater the separation of the images.\\nWith the above explanation, it is easy to see why the images\\nalways overlap when the astigmatism is with the rule and why\\nthey always separate when the astigmatism is against the rule.\\nConsequently, when we have an eye under observation with\\nthe ophthalmometer, we know immediately, if on turning the\\narc from the primary position to the secondary position and an\\noverlapping of the images occurs, that we have astigmatism\\nwith the rule. If, however, the images separate when the arc\\nis turned from the primary to the secondary position, we know\\nat once that the astigmatism is against the rule.\\nThe instrument, therefore, says something and means some-\\nthing when the images either overlap or separate. If the\\nimages neither overlap nor separate on turning the arc from", "height": "4258", "width": "2698", "jp2-path": "refractionofeye00davi_0046.jp2"}, "47": {"fulltext": "WHY ONE-HALF DIOPTER IS DEDUCTED 29\\nthe primary to the secondary position, it shows that there is no\\ncorneal astigmatism at all. In such cases the patient some-\\ntimes takes a weak cylindrical glass (about .50 D.) against the\\nrule, that is, .50 D. cylindrical axis at 180\u00c2\u00b0 or near it, if the\\npatient is hypermetropic or .50 D. cylindrical axis 90\u00c2\u00b0 or\\nnear it, if the patient is myopic. This is explained by the\\npresence of a small amount of lenticular astigmatism which is\\nnearly always present, and against the rule.^ Consequently\\nwe should be on the lookout for this in such cases. Many\\ntimes, however, when the ophthalmometer shows no corneal\\nastigmatism the patient accepts no cylindrical glass at all.\\nWhy do we deduct half a diopter from the reading of the in-\\nstrument luhen the astigmatism is with the rule, and why do ive\\nadd half a diopter to its reading when the astigmatism is against\\nthe rule? The above question is often asked, and perhaps\\nthe correct answer and true explanation of same is to be found\\nin the lenticular astigmatism present in most cases.\\n1. In astigmatism with the rule we usually have to deduct\\nhalf a diopter from the reading of the instrument, that is, the\\npatient- will not accept as much as the instrument gives by\\n.50 D. This can be explained quickest and best by an illus-\\ntrative case. Say the instrument reads astigmatism with the\\nrule 2.50 D., axis 90\u00c2\u00b0 -f or 180\u00c2\u00b0 We will assume also, for\\nthe sake of simplicity, that it is a case of simple hyperme-\\ntropic astigmatism. Figure 21 shows a vertical and horizontal\\nsection of such an eye and where the rays of light focus. A\\nfront view of the cornea and lens is also given in order to show\\nthe outlines of their front surfaces. It is evident that, in\\norder to have the rays of light in the vertical meridian focus on\\nthe retina, both the cornea and the lens must be emmetropic\\nin the vertical meridian.\\n1 Or it may be accounted for by an astigmatism of the posterior surface of\\nthe cornea, which sometimes amounts to as much as 1 D.\\n2 At least their combined refractive power must be emmetropic in effect.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0047.jp2"}, "48": {"fulltext": "80\\nTHE REFRACTION OF THE EYE\\nBut the horizontal meridian of the cornea is flatter by\\n2.50 D. than the vertical meridian, as measured by the in-\\nstrument and if the patient had no lenticular astigmatism,\\nit would require a 2.50 D. cylindrical glass to correct this\\nand bring the rays to a focus on the retina. But as a matter\\nof fact in such a case the patient usually will accept but 2 D.\\ncylindrical glass. This can be explained best, it seems to me,\\nby assuming a lenticular astigmatism, myopic in nature, of\\n.50 D. in the horizontal meridian. This would neutralize that\\nVERT. MERID.\\nM. .50 D.\\nFig. 21. Vertical and horizontal sections of the right eye: also front view of the\\ncornea and the lens simple hypermetropic astigmatism with the rule.\\namount (.50 D.) of the hypermetropic corneal astigmatism in\\nthe same meridian, leaving but 2 D. of total astigmatism to be\\ncorrected by a glass.\\nWhat is true in hypermetropic cases is also true in myopic\\ncases as see Fig. 22.\\nHere the diagram shows a case of simple myopic astigmatism\\nwith the rule 2.50 D. axis 90\u00c2\u00b0+ and 180\u00c2\u00b0 In order to have\\nthe rays of light in the horizontal meridian focus on the retina,\\nboth the cornea and lens must be emmetropic in the horizontal\\nmeridian (that is, their combined refractive power). But the", "height": "4259", "width": "2698", "jp2-path": "refractionofeye00davi_0048.jp2"}, "49": {"fulltext": "WHY ONE-HALF DIOPTER IS ADDED\\n31\\nvertical meridian of the cornea is more curved than the horizon-\\ntal by 2.50 D. as shown by the ophthalmometer, therefore it\\nwould require a\u00e2\u0080\u0094 2.50 D. cylindrical glass, axis 180\u00c2\u00b0, to cor-\\nrect it, if no lenticular astigmatism was present. As a rule the\\npatient will accept but a 2 D. cylindrical glass. This is to\\nbe accounted for by the lens being hypermetropic astigmatic\\n.50 D. in the vertical meridian, thereby neutralizing that amount\\nof the corneal astigmatism, and but 2 D. of total astigmatism\\nis left to be corrected.\\nFig. 22. Vertical and horizontal sections of the right eye also front view of the\\ncornea and the lens; simple myopic astigmatism with the rule.\\nThe lenticular astigmatism is not always exactly .50 D., but\\nmay be more or less. Sometimes it is only .25 D., or may be\\nabsent. Again, it may amount to .75 D., or 1 D., and excep-\\ntionally to even larger amounts. As a rule, however, it amounts\\nto .50 D. or .75 D., and in astigmatism with the rule, it being\\nof an opposite kind to the corneal astigmatism, it neutralizes\\nto that extent the corneal astigmatism. And that is why we\\ndeduct such amount from the reading of the instrument Avhen\\nthe astigmatism is with the rule.\\n2. In astigmatism against the rule we usually have to add", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0049.jp2"}, "50": {"fulltext": "32\\nTHE REFRACTION OF THE EYE\\na half diopter to the reading of the instrument, that is, the\\npatient accepts that much more.\\nIllustrative cases will serve to explain better than anything\\nelse. Say the ophthalmometer reads, astigmatism 2.50 D.\\nagainst the rule, axis 180\u00c2\u00b0 90\u00c2\u00b0 To simplify matters we\\nwill assume it to be a case of simple hypermetropic astigmatism.\\nIt is plain from Fig. 23 that both the cornea and lens are\\nemmetropic in the horizontal meridian because the rays of light\\nVERT. MERID.\\nHOR. MERID.\\nH. 2.50 D.\\nCORNEA\\nFig. 23. Vertical and horizontal sections of an eye with simple hypermetropic\\nastigmatism against the rule; also front view of the cornea and the lens in\\noutline.\\npassing through this meridian focus on the retina. But the in-\\nstrument shows the vertical meridian of the cornea to be flatter\\nby 2.50 D. than the horizontal meridian and if no lenticular\\nastigmatism was present it would take a -f2.50 D. cylindrical\\nglass axis 180\u00c2\u00b0 to correct same. As a matter of fact, the patient\\nusually accepts a half diopter more than the instrument says.\\nThis can be accounted for by a half diopter (.50 D.) of len-\\nticular astigmatism in the vertical meridian, hypermetropic in\\nnature, and, therefore, of the same kind as the corneal astig-\\nmatism. In other words, both the cornea and lens are hyper-\\nmetropic in the vertical meridian, the cornea 2.50 D. and the", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0050.jp2"}, "51": {"fulltext": "PRINCIPAL MERIDIANS AT 45\u00c2\u00b0 AND 135\u00c2\u00b0 33\\nlens .50 D., the two added together making 3 D. the total\\nastigmatism, consequently it requires a 3 D. cyl. axis 180\u00c2\u00b0\\nto correct same.\\nThe same law holds true in myopic cases.\\nMany times, however, in astigmatism against the rule, the\\npatient accepts exactly the glass indicated by the ophthal-\\nmometer, showing that lenticular astigmatism is often entirely\\nabsent in such cases.\\nThe whole of the explanation given above on this question\\nmay be summed up in two short sentences.\\n1. In astigmatism with the rule the lenticular astigmatism is\\nin the same meridian as the corneal astigmatism, but is of an\\nopposite kind, and usually amounts to lialf a diopter, thereby\\nneutralizing that amount of the corneal astigmatism.\\n2. In astigmatism against the rule the lenticular astigma-\\ntism is in the same meridian as the corneal astigmatism, is of\\nthe same kind, and usually amounts to half a diopter, therefore\\nadds that amount to the corneal astigmatism.\\nBefore closing this chapter there is one final point I wish to\\nelucidate, and that is the reading of the ophthalmometer when\\nthe two chief meridians of curvature of the cornea happen to\\nbe at 4,5\u00c2\u00b0 and 135\u00c2\u00b0, or exactly halfway between 0\u00c2\u00b0 and 90\u00c2\u00b0 on\\none side, and 90\u00c2\u00b0 and 180\u00c2\u00b0 on the other side.\\nWe know that in astigmatism both with and against the rule\\nthat the two main meridians of curvature of the cornea are at\\n90\u00c2\u00b0 and 180\u00c2\u00b0, or in their neighborhood. When the meridian\\nat 90\u00c2\u00b0 or its neighborhood is the more curved, as it usually is,\\nit is astigmatism with the rule but if this meridian happens to\\nbe less curved it is astigmatism against the rule.\\nThere are certain exceptional cases where the two chief\\nmeridians of curvature of the cornea are just halfway be-\\n1 1 am not unmindful of the fact that the unequal curvature of the posterior\\nsurface of the cornea can and may modify the astigmatism of the front surface\\nof the cornea. I think, however, the lens plays the more important role.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0051.jp2"}, "52": {"fulltext": "34 THE REFRACTION OF THE EYE\\ntween 0\u00c2\u00b0 and 90\u00c2\u00b0, and 90\u00c2\u00b0 and 180\u00c2\u00b0, that is, exactly at 45\u00c2\u00b0\\nand 135\u00c2\u00b0 (see Fig. 24).\\nNow 45\u00c2\u00b0 is no nearer to 90\u00c2\u00b0 than it is\\n90\u00c2\u00b0\\n135^^^ PX^s consequently it is not in the neigh-\\nborhood of one or the other. So with\\n135\u00c2\u00b0 as regards 90\u00c2\u00b0 and 180\u00c2\u00b0, it is just\\nas near one as the other, and is not in\\nFig. 24. -Front view of the neighborhood of either.\\nan eye showing the ttt-i j t.\\ntwo chief meridians What are we to do m such a case as\\nof curvature at 45 regards astigmatism with the rule and\\nastigmatism against the rule Strictly\\nspeaking, in such cases, there is no such thing as astigmatism\\nwith the rule and astigmatism against the rule, simply\\nbecause the two chief meridians of curvature are exactly on\\nthe halfway mark or dividing lines of what it takes to make\\nastigmatism with, or against, the rule. But how does the\\nophthalmometer work in such cases In such cases we search\\nfor the primary position as usual (see rule 5, p. 17), by begin-\\nning with the long indicator at 0\u00c2\u00b0. We know when we are\\nin the primary position by the two narrow black lines which\\ndivide the mires into halves becoming straight with and oppo-\\nsite each other, which they do when either of the chief meri-\\ndians of curvature of the cornea is reached. In the present\\ncase these lines would not be straight when we turned the\\nlong indicator to 0\u00c2\u00b0, because neither of the chief meridians\\nis here. Following the directions in rule 5, we turn the long\\nindicator from 0\u00c2\u00b0 toward 135\u00c2\u00b0, when 135\u00c2\u00b0 is reached (one\\nof the chief meridians of curvature in this instance) the narrow\\nblack lines dividing the mires become straight with each\\nother. This is the primary position. We then approximate\\nthe images and turn the arc at right angles to the primary\\nposition (the long indicator to 45\u00c2\u00b0) to obtain the secondary\\nposition. If the meridian at 45\u00c2\u00b0 proves to be more curved\\nthan the one at 135\u00c2\u00b0 the images will overlap.", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0052.jp2"}, "53": {"fulltext": "PRBSrCIPAL MERIDIANS AT 45\u00c2\u00b0 AND 135\u00c2\u00b0 35\\nAccording to the language of the instrument, that is,\\nwhen overlapping occurs, it means astigmatism with the rule,\\nthis would be a case of astigmatism with the rule. Though,\\nas a matter of fact, we know and have just explained above,\\nthat there is really no such thing as astigmatism with or\\nagainst the rule, when the chief meridians of curvature are at\\n45\u00c2\u00b0 and 135\u00c2\u00b0. However, for the sake of uniformity of expres-\\nsion and to make the words of the instrument overlapping\\nand separation of the images mean a definite something in\\nevery case^ it is well to apply the terms astigmatism with\\nthe rule and astigmatism against the rule, even to the\\nmeridians at 45\u00c2\u00b0 and 135\u00c2\u00b0.\\nIt is altogether important also in such cases to take either\\n135\u00c2\u00b0 or 45\u00c2\u00b0 one or the other always as the primary posi-\\ntion, and not first one and then the other as the primary posi-\\ntion. A glance at Fig. 24 will show why this is necessary.\\nIf we start at 135\u00c2\u00b0 as the primary position, the meridian of\\nlongest radius of curvature, and then turn to 45\u00c2\u00b0, the secondary\\nposition, to the meridian of shortest radius of curvature, the\\nimages will overlap, showing astigmatism with the rule. How-\\never, should we take 45\u00c2\u00b0 as the primary position, the meridian\\nof shortest radius of curvature, and then turn to 135\u00c2\u00b0, at right\\nangles, a meridian with the longer radius of curvature, the\\nimages would separate, showing thereby astigmatism against\\nthe rule. In other words, the instrument would say astigma-\\ntism with the rule and against the rule, in the same eye^ accord-\\ningly as we assumed 135\u00c2\u00b0 or 45\u00c2\u00b0 as the primary position. As\\nwe cannot very well have astigmatism both with and against the\\nrule in the same eye, it is best, in such cases as the above, to\\nassume one or the other of these meridians always as the pri-\\nmary position. Individually, and in the rules which I have\\nformulated for the use of the instrument, I assume 135\u00c2\u00b0 always\\nas the primary position in such cases. The meridian at 45\u00c2\u00b0\\ncould be taken just as well, provided it was always taken as\\nthe starting or primary position.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0053.jp2"}, "54": {"fulltext": "CHAPTER III\\nGENERAL CONSIDERATIONS IN THE USE OF THE OPHTHAL^\\nMOMETER SIMPLE HYPERMETROPIC ASTIGMATISM\u00e2\u0080\u0094 SIMPLE\\nHYPERMETROPIA ILLUSTRATIVE CASES\\nIt is well to state here that the ophthalmometer does not,\\nexcept in an indirect way, which is not at all reliable, indicate\\nthe nature of the error of refraction, that is, if it is hyper-\\nmetropic or myopic in character. All that it does is to measure\\nthe front surface of the cornea. If the cornea is uniformly\\ncurved in all of its meridians, the instrument shows it by the\\nimages of the mires not overlapping or separating in any posi-\\ntion after they have once been brought in apposition. If the\\ncornea is not uniformly curved,^ that is, if astigmatism is pres-\\nent, it measures the difference in the radius of curvature of\\nthe two chief meridians, thereby measuring the amount of the\\nastigmatism and also indicates the position of these two chief\\nmeridians. Of the nature of the error, if hypermetropic or\\nmyopic, we have to find out by the use of the trial lenses, the\\nophthalmoscope, the retinoscope, and at rare intervals we may\\nbe obliged to use atropine or some other mydriatic in addition\\nfor, as above stated, the ophthalmometer points to the nature\\nof the error only in an indirect way, as follows for example,\\nsay we find the primary position at 0\u00c2\u00b0 or 180\u00c2\u00b0, and that when\\nthe images of the mires just touch in this position that the\\nradius of curvature on the cornea in this meridian is just\\n1 Of course it is a well-established fact that the cornea is slightly elliptical in\\nshape, but when the images of the mires neither overlap nor separate at any-\\nmeridian on the cornea after once approximated, we may say it is spherical in\\nshape.", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0054.jp2"}, "55": {"fulltext": "GENERAL CONSIDERATIONS 37\\n7.8 mm., which is the average radius of curvature of a normal\\ncornea. By noticing the position of the graduated mire in its\\nrelation to the millimeter marks on the anterior edge of the arc,\\nin such a case, it will be seen that the fine mark or line on the\\nbase of the mire stands just at 7.8 mm. Say now we turn the\\narc to the second position and the images overlap five steps.\\nThis would show that the vertical meridian was more curved\\nthan the horizontal, and to the extent of 5 diopters. If, then,\\nin this position the images are withdrawn from their overlap-\\nping, so that they just touch again, it will be found that the\\nfine mark on the graduated mire stands opposite, or nearly so,\\nthe 7 mm. mark, showing a shorter radius of curvature in this\\nvertical meridian.\\nSince the horizontal meridian had the normal radius of cur-\\nvature, the vertical meridian with a shorter radius of curvature-\\nwould indicate, indirectly to be sure, myopic astigmatism iu\\nthe vertical meridian. On the other hand, had one found the\\nhorizontal meridian with a considerable longer radius of curva-\\nture than the average, say 8.5 mm., and then on turning to the\\nvertical meridian, or second position, we found the radius of\\ncurvature in this meridian to be just 7.8 mm., the average\\nradius of curvature, we might assume that the horizontal\\nmeridian in this instant was hypermetropic in nature on ac-\\ncount of its long radius of curvature, 8.5 mm.\\nValk, in an examination of over five hundred cornefe with\\nthe ophthalmometer, found the average normal radius of curva-\\nture to be only 7.65 mm., a considerable shorter radius than is\\ncommonly accepted as the average (7.8 mm.).\\nProceeding on this assumption, he draws the following con-\\nclusion from his examination of cases\\nThat the radius of curvature bears a certain definite rela-\\ntion to the refractive condition of the eyes, in which, if we find\\nthat the radius of curvature is greater than 7.65 mm., that the\\nrefraction is probably hypermetropic, as we find only one in", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0055.jp2"}, "56": {"fulltext": "38 THE REFRACTION OF THE EYE\\nten myopic on the other hand, if the radius of curvature is\\nless than 7.60 mm., that the refraction is myopic, as now the\\nproportion is found to be one in three.\\nIn this conclusion he differs from almost all other observers.\\nBonders long ago made similar measurements, and came to the\\nconclusion that there was no definite relation between the radius\\nof curvature of the cornea and the refractive condition of the\\neye. He says A priori it might be supposed, and it has\\nbeen not only supposed, but also asserted, that less convexity\\nof the cornea and of the crystalline lens is peculiar to the hyper-\\nmetropic eye. So far as the cornea is concerned, I am justified\\nby the results of numerous accurate determinations, in denying\\nthe assertion. Even in high degrees of H., the radius in the\\nvisual line (compare p. 89) is nearly equal to that in the em-\\nmetropic eye in the highest degrees, when the circumference\\nof the cornea is somewhat less than usual, I found the radius\\neven less.\\nThe same author draws a similar conclusion in regard to\\nmyopia, that is, that the radius of curvature of the cornea\\nbears no definite relation to the refractive condition present.\\nIn extreme degrees of myopia, on the contrary, a somewhat\\nflatter cornea is met with.*\\nHe, of course, admits such a thing as curvature myopia and\\nhypermetropia, but his ultimate conclusion is, That myopia\\nusually depends upon an elongation^ and hypermetropia upon a\\nshortening^ of the axis of vision.^ All subsequent observers have\\nconfirmed this view.\\nSchiotz^ also has made special investigation with the ophthal-\\nmometer as to the corneal curvature in cases of hypermetropia,\\n1 Ophthalmic Eecord, June, 1897.\\n2 Accommodation and Befraction of the Eye, pp. 88, 89, 246.\\n3 Ibid., p. 246.\\nIhid., p. 88.\\n5 Cited by A. Javal, Jr. System of Diseases of the Eye, Norris and Oliver,\\nVol. H, p. 127.", "height": "4259", "width": "2698", "jp2-path": "refractionofeye00davi_0056.jp2"}, "57": {"fulltext": "significa:n^ce of radius of curvature of cornea 39\\nmyopia, and emmetropia, but found no definite law or relation\\nto exist.\\nA. Javal,^ in commenting on this subject, says\\nIt is, in fact, remarkable how greatly the radius of curva-\\nture may vary for the same refractive condition. In emme-\\ntropia the radii of curvature as measured by Schiotz varied\\nbetween the limits 8.657 mm. and 7.243 mm., or, in diopters,\\nbetween 38.8 D. and 45.3 D., a difference of not less than\\n6.5 D.\\nFrom these figures it would appear that variations in the\\nradius of corneal curvature do not play any great role in\\ndetermining the refraction.\\nA still more conclusive proof is afforded by observations\\nmade on antimetropes. As a rule, in such persons we find the\\nsame radius of corneal curvature in both eyes, even when one\\nof these eyes is highly myopic.\\nI must say that my experience has been that of the great\\nmajority of observers, in not finding any definite relation to\\nexist between the radius of corneal curvature and the refractive\\ncondition of the eye. And even if the definite relation that\\nValk claims existed, it would be of no value in the fitting of\\nglasses. For under the most favorable circumstances, that is,\\nwhere the radius was found by the ophthalmometer to be less\\nthan 7.60 mm., my5pia was absent in QQ^ per cent of the cases\\nwhile in the most unfavorable conditions, that is, where the\\nradius was over 7.65 mm., it was absent in 90 per cent of the\\ncases. Therefore on an average it failed in 78 per cent of all\\ncases, or was right in but 22 per cent of cases. When it is\\nremembered that myopia forms 16 to 20 per cent of all refractive\\ncases, take them as they come, it will be seen of what little\\nvalue Valk s definite relation of corneal radius to the existing\\nrefractive condition amounts to.\\nThe ophthalmometer then shows the presence or absence\\n1 Loc. cit.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0057.jp2"}, "58": {"fulltext": "40 THE REFRACTION OF THE EYE\\nof astigmatism if present, whether it is with or against the\\nrule, the amount, and the axes of the main meridians. It does\\nnot, except in a very indefinite way, as just pointed out above,\\nindicate the character of the error of refraction, whether hyper-\\nmetropic or myopic. This latter point, in the great majority of\\ncases, is easily determined, and most of the time by the simple\\nsubjective test with the test cards and trial lenses, that is, if the\\ntest is begun properly. If not revealed by the trial lenses, then\\nfurther objective tests with the ophthalmoscope and retinoscope\\nwill reveal the nature of the error, except in a very limited\\nnumber of cases in subjects under twenty years of age, when a\\nmydriatic must be called into requisition.\\nIn my practice, both private and hospital, I do not use a\\nmydriatic in more than one per cent of all cases of refraction.\\nAnd I may say here, that I agree with my illustrious teacher\\nand preceptor, D. B. St. John Roosa, on this point, that it is\\nnot necessary to use atropine or mydriatics of any kind, except\\nin rare instances.^ The soundness of this practice is amply\\nborne out in my private practice and in the clinic at the\\nManhattan Eye and Ear Hospital. In 1891 I took all the\\ncases of refraction consecutively that came to the clinic of\\nDrs. Roosa and Lewis, and found that a mydriatic was used\\nbut once in every sixty-four cases, or in about 1.5 per cent of\\nall cases of refraction. In 1896, in the same clinic for a period\\nof six months, atropine was not used in a single case uncompli-\\ncated with squint.2\\nIn squint cases it is advisable to use a mydriatic so as to\\ngive a full, or almost full, correction of the error of refraction,\\nand in that way aid in straightening the eye. But in ordinary\\nuncomplicated cases of refraction, I repeat, it is rarely necessary\\nor advisable to use any mydriatic whatever. Furthermore, it\\n1 Hirschberg, George J. Bull, Dennett, and many others hold the same\\nopinion as to the use, or rather non-use, of mydriatics.\\n2 D. B. St. John Roosa, Manhattan Eye and Ear Hospital Beport, 1896.", "height": "4260", "width": "2698", "jp2-path": "refractionofeye00davi_0058.jp2"}, "59": {"fulltext": "ROUTINE OF EXAMINATION 41\\nmay be remarked that since we have used the ophthalmometer\\nat the Manhattan Eye and Ear Hospital clinics, and depended\\non it almost to the exclusion of atropine, that we have changed\\nfewer glasses than formerly, when atropine was used in nearly\\nevery case under forty years of age. The same holds true in\\nmy private practice.\\nWhen we take into account the time and great annoyance\\nsaved to the patient by not using atropine, we can readily see\\nthe.advantages of an ophthalmometer. In fact, many business\\nmen will not tolerate a mydriatic and one can hardly blame\\nthem when it is known that their eyes can be tested, with rare\\nexceptions, just as well or better without atropine than with it.\\nIf the following routine of examination, which I shall now\\ngive, is followed out, 99 per cent of all uncomplicated cases of\\nerror of refraction can be fitted without the use of mydriatics.\\n1. Use the ophthalmometer.\\n2. Use trial lenses and test cards.\\n3. Use the ophthalmoscope.\\n4. If after two tests on different days the result is still\\nunsatisfactory, employ a mydriatic and use the retinoscope in\\naddition to the other tests.\\nThe reason that I do not, as a rule, use the ophthalmoscope\\nbefore testing with the trial lenses is that if light is thrown\\ninto the eye for a prolonged time, it dazzles the sight and\\nimpairs the value of an immediate test with the trial lenses.\\nIf I have much trouble, however, in finding the proper glass,\\nI do not hesitate to use the ophthalmoscope to find the nature\\nof the error of refraction, or if any pathological condition of\\nthe eye exists then let the patient wait a short while before\\nthe subjective test with the trial lenses is again undertaken.\\nSimple cases of hypermetropia and myopia are, as a rule,\\neasily fitted to glasses but a certain definite method should\\nbe followed even in these cases. It is the astigmatic cases\\nthat give most trouble, and among these, as is well known, the", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0059.jp2"}, "60": {"fulltext": "42 THE REFRACTION OF THE EYE\\ncompound hypermetropic and mixed astigmatisms are the most\\ndifficult to fit.\\nAstigmatism is the thing of most importance in correcting\\nerrors of refraction, and I invariably correct the astigmatism\\nfirst, unless there is a large amount of spherical error present\\na myopia of 8 diopters or more, or a hypermetropia of 6\\ndiopters or more with only a small amount of astigmatism.\\nIn such cases, part of the spherical error is first to be corrected,\\nin order, if possible, to bring up the vision sufficiently, so that\\nthe eye will appreciate any further change in acuity of vision\\nwhen a weak cylindrical glass is placed in front of it.\\nI always begin my test by putting on plus glasses plus\\ncylindrical glasses if astigmatism is present, plus spherical\\nglasses if astigmatism is absent, and for the following reasons\\nFirst, because we do not know if the patient is hypermetropic\\nor myopic. If the patient happens to be hypermetropic, plus\\nglasses are accepted, as a rule, if begun with however, if minus\\nglasses are first tried, the patient many times accepts them,\\nespecially if the error is of low amount, though the patient is\\nreally hypermetropic. This fact is so well known that it is\\nhardly necessary to more than merely allude to it. The eye\\ninstinctively makes an effort to overcome minus glasses when\\nplaced in front of it, the ciliary muscle is thrown into a spasm\\nof accommodation, producing an artificial myopia, which the\\nminus glass partly or wholly corrects, and in this way appar-\\nently improves vision. The mere fact that a patient accepts\\nminus glasses is no indication whatever that he has myopia.\\nFurthermore, minus glasses should never be tried until plus\\nglasses have been tried, unless we know beforehand that the\\npatient is really myopic, for they tend to incite a spasm of\\naccommodation, which is the very thing we wish to avoid.\\nThe thing of next importance to plus glasses in beginning a\\ntest is that we shall begin with the weakest lenses in the trial\\ncase, and go up gradually. I do this also to avoid spasm of", "height": "4262", "width": "2698", "jp2-path": "refractionofeye00davi_0060.jp2"}, "61": {"fulltext": "ROUTINE OF EXAMINATION 43\\naccommodation, for by adding a quarter of a diopter at a time\\nthe eye accustoms itself to it, and the ciliary muscle relaxes\\ngradually if it is only given a chance.\\nShould all, or almost all, of the correction be put on at once,\\nhowever, the change for the eye is so sudden and marked that\\nit will not adjust itself to it whereas, had the glasses been\\ngradually increased in power, the ciliary muscle would have\\nrelaxed. This is my experience, and I believe it accords with\\nthat of the great majority of observers.\\nBy following this plan, spasm of accommodation, if present,\\ncan, in the great majority of cases, be overcome, and if not\\npresent, the liability of causing it be avoided.\\nAnother method of avoiding spasm of accommodation, and\\none well known among oculists, is to correct both eyes at the\\nsame time.\\nNot only do I follow the above routine, but under step No.\\n2 I follow a certain routine in putting the glasses in the trial\\nframes during the subjective tests. Bearing in mind always to\\nbegin the test with a plus glass (unless we know beforehand\\nthe patient to be myopic), and a weak plus glass, and to grad-\\nually increase the strength of the glass, in order to avoid or\\novercome spasm of accommodation, I proceed in the following\\nmanner When the ophthalmometer indicates astigmatism, first\\ntry plus cylindrical glasses alone second, plus spherical glasses\\nin addition third, minus cylindrical glasses at right angles to\\nthe plus cylindrical glass, if vision is not made perfect b}^ a\\n1 Some oculists, however, resort to putting on very mucli too strong plus\\nglasses, which blur the vision completely, and in that way take away the desire\\nto accommodate for or fix on any object. Then, by gradually diminishing the\\npower of the glass, the correct glass is finally accepted. For myself, I much\\nprefer to begin with the weakest, and work up.\\n2 For instance, if the ophthalmometer should indicate 4 diopters of astigma-\\ntism, with the rule, 90\u00c2\u00b0+ or 180\u00c2\u00b0 and the patient would accept only +2 D.\\ncyl, axis 90\u00c2\u00b0, with improvement of vision, but would accept no plus spherical\\nglass in addition, mixed astigmatism is at once suspected, and minus cylindrical\\nglasses are tried at right angles to the plus cylinder.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0061.jp2"}, "62": {"fulltext": "44 THE REFRACTION OF THE EYE\\nplus cylindrical glass alone, and plus spherical glasses are not\\naccepted in addition fourth, minus cylindrical glasses alone\\nfifth, minus spherical glasses in addition.\\nWhen the ophthalmometer indicates but one-half a diopter\\nof astigmatism with the rule, usually the lenticular astigmatism\\nneutralizes that amount of corneal astigmatism, and the patient\\nwill not accept any cylindrical glass. In such cases we are\\nmost of the time dealing with cases of simple hypermetropia\\nand myopia, and proceed at once to try plus spherical glasses,\\nand, if not accepted, minus spherical glasses. However, should\\nthere be only a very small amount of hypermetropia or myopia,\\nand the patient s sight is not improved by the spherical glasses,\\nit is well to try a weak cylinder, plus first, then minus. This\\nis for two reasons first, we may have made an error with the\\nophthalmometer in the estimation of the amount of the astig-\\nmatism second, the lenticular astigmatism might not be suffi-\\ncient to neutralize the half diopter of corneal astigmatism, or it\\nmight more than neutralize it, when it would result in a small\\namount of astigmatism against the rule.\\nIt has been maintained by some authorities that the ophthal-\\nmometer is not of value in cases of simple myopia and hyper-\\nmetropia, an opinion from which I beg to differ. In cases of\\nhypermetropia and myopia it eliminates the question of corneal\\nastigmatism. This is a very important factor, for with no\\nastigmatism present the tests for glasses are usually very easily\\nmade. The ophthalmometer is of great value in a negative way,\\ntherefore, even in cases of simple hypermetropia and myopia.\\nIllustrative cases of simple hypermetropic astigmatism and\\nhypermetropia. In giving illustrative cases I shall first take a\\ntypical case, giving the tests for its detection and correction in\\ndetail then other cases showing different amounts of astig-\\nmatism and different axes, and cases against and with the rule\\nwill be taken. In many cases diagrams of the sections of the\\neye under observation through its two chief meridians of cur-", "height": "4262", "width": "2698", "jp2-path": "refractionofeye00davi_0062.jp2"}, "63": {"fulltext": "ILLUSTRATIVE CASES 45\\nvature are given. This is done in order to have the reader\\nthink of the eye as it is^ to see where the rays of light entering\\nsuch an eye focus, and how the proper glasses correct the error\\nof refraction in such a case. It has been my experience that\\nstudents at least do not think of the eye under observation, but\\ntry to fit the patient to glasses by following some rule in a book.\\nThey put the glasses on empirically; if they improve vision,\\nvery well, they are satisfied with that and do not worry them-\\nselves much about the why or the wherefore; if the glasses do\\nnot improve vision, they are at a loss to know why, and many\\ntimes give a wrong glass. Beginners, especially, are in doubt\\nin cases where there is marked amblyopia present, where a\\npatient will accept even a strong plus glass without improve-\\nment in vision. This is a common occurrence in cases of con-\\nvergent squint, where, as is well known, usually a large amount\\nof hypermetropia is present, especially in the squinting eye.\\nThough there may not be any lesion of the fundus in either\\neye, the squinting eye is usually very weak-sighted or amblyopic,\\nand will accept plus glasses without improvement in vision, or\\nwith only very slight improvement. It is very important that\\nsuch an eye should have the right glass, yet, if the examiner is\\nnot sure of the correctness of his examination and correctly\\ninformed in optics, he might hesitate as to giving the glasses\\non account of the lack of improvement in vision. It is in just\\nsuch cases of amblyopia, especially when the amblyopia happens\\nto be in the case of a child or an ignorant person, that the\\nophthalmometer is of such great advantage.\\nCase I. Corneal astigmatism with the rule^ 1 D., axis\\n90\u00c2\u00b0 -f or 180\u00c2\u00b0-; Patient accepts .^0 B. cyl,, axis 90\u00c2\u00b0.\u00e2\u0080\u0094\\nApril 6, 1892, Nellie H., aged twenty-three years, in good gen-\\neral health, has had trouble with her ej^es for about two years.\\nAfter any continuous work, especially at night, her eyes burn\\n1 These diagrams are not meant to be mathematically correct, and are used\\n:simply to make the subject matter plainer.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0063.jp2"}, "64": {"fulltext": "46\\nTHE REFRACTION OF THE EYE\\nVERT. MERID.\\nand ache, and often headaches follow. There is some redness\\nof the edges of the eyelids and congestion of the conjunctiva.\\nOphthalmometer. Astigmatism with the rule, 1 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 in each eye.\\nFigure 25 shows the general shape of the cornea, front\\nview, in this case. Since the astigmatism is with the rule, the\\nvertical meridian must be\\nmore curved, that is, have^\\na shorter radius of cuiwa-\\nture than the horizontal.\\nWe do not know, how-^\\never, from the examination\\nwith the ophthalmometer\\nwhether the error of refrac-\\ntion is hypermetropic or\\nmyopic in character that\\nmust be found out by sub--\\nsequent tests.\\nUnless from the history\\nof the case I have reason\\nto suspect some pathological lesion of the eye, I next try the\\ntrial lenses and test cards. I do this, first, for the very good\\nreason that most cases reveal the nature and extent of the\\nerror of refraction simply by the use of the ophthalmometer\\nand trial lenses; second, because we do not have to delay the\\ntest with the trial lenses as we do where the ophthalmoscope ia\\nfirst used, for the light thrown into the eye by an extended\\nophthalmoscopic examination dazzles the eye and requires some\\ndelay afterward before the subjective test can be completed.\\nTest cards and trial lenses. The horizontal lines on Green s,\\nclock dial were seen plainest in this case.\\nI^- M ff W- D. cyl., 90\u00c2\u00b0.\\nL. V. 1^ ff W. .50 D. cyl., 90\u00c2\u00b0.\\nReads Jaeger No. 1 from 6 to 15 inches.\\nFig. 25.", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0064.jp2"}, "65": {"fulltext": "ILLUSTRATIVE CASES 47\\nBearing in mind to correct the astigmatism first, if any is\\npresent, and proceeding with the test, as directed on page 42,\\nby beginning with a weak plus glass, the first glass tried\\nwas .25 D. cyl., 90\u00c2\u00b0 (as indicated by the ophthalmometer).\\nThis improved vision somewhat, so the next stronger cyl.,\\n.50 D., axis 90\u00c2\u00b0, was tried; this improved vision still more.\\nThe next stronger cyl., 75 D., axis 90\u00c2\u00b0, made the vision\\nworse. A .50 D. cylindrical glass then was the strongest\\ncylinder that gave the best vision. To see if any manifest\\nhypermetropia was present in addition to the astigmatism,\\n.25 D. spherical glass was placed in front of the .50 D.\\ncylindrical glass; it made vision worse, showing no manifest\\nhypermetropia to be present.\\nThe same mode of procedure was followed in the left eye,\\nthe patient accepting a .50 D. cylindrical glass, axis 90\u00c2\u00b0,\\nand obtaining the best vision, in each eye.\\nOphthalmoscope. Hypermetropic astigmatism with the\\nrule, .50 D., axis 90\u00c2\u00b0, in each eye; no pathological lesion of\\nthe fundus in either eye.\\nThe patient accepted the same glass on the second test, two\\ndays later and .50 D. cyl., axis 90\u00c2\u00b0, was prescribed for each\\neye.\\nThe retinoscope and mydriatics were not used in this case,\\nas they were not deemed necessary. A mild astringent wash\\nwas prescribed for the slight inflammation of the lids. Octo-\\nber 17, 1895, three and a half years later, the patient returned\\non account of a slight conjunctivitis. With mild astringents\\nthis was cured in three weeks time. The glasses were still\\nsatisfactory.\\nCase II. Astigmatism with the rule, 4 D., axis 10\u00c2\u00b0, to the\\ntemporal side of the vertical meridian in each eye; Patient com-\\nplains of no asthenopia, hut simply of poor vision; Accepts 3.50\\nD. cyl. in each eye. December 5, 1894, O. M., aged twenty-\\nsix years, in robust health, consulted me on account of poor", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0065.jp2"}, "66": {"fulltext": "48 THE REFRACTION OF THE EYE\\nvision. The remarkable thing about this case is that the\\npatient never complained of asthenopia, though the tests\\nshowed him to have such a high degree of hypermetropic\\nastigmatism. He never saw well, and noticed at school that\\nhe could not see as well as his companions. At night he\\ncould not read ordinary print.\\nOphthalmometer. Astigmatism with the rule, 4 D., axis\\n100\u00c2\u00b0 or 10\u00c2\u00b0 right eye 4 D., axis 80\u00c2\u00b0 or 170\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nR. V. JJL: |o w. 3.50 D. cyl., 100\u00c2\u00b0.\\nL. V. 2^%: fl W. 3.50 D. cyl., 80\u00c2\u00b0.\\nReads Jaeger No. 1 from 4 to 12 inches.\\nOphthalmoscope. Simple hypermetropic astigmatism in\\neach eye. Two days after the first test a second test was\\nmade, and the patient accepted the same glass, which was\\nordered. The patient was seen two years later and the glasses\\nwere satisfactory.\\nCase III. Corneal astigmatism with the rule .50. i)., neu-\\ntralized hy lenticular astigmatism Patient accepts simple plus\\nspherical glass. October 3, 1893, M. B. H., aged thirty-\\nthree, general health is very good, but she is not robust.\\nShe complains of headaches and blurring of vision when she\\nreads. The patient has worn glasses for the last two years,\\nbut without benefit.\\nOphthalmometer. Astigmatism with the rule, .50 D., axis\\n90\u00c2\u00b0+ or 180\u00c2\u00b0 -each eye.\\nTest cards and trial lenses. All of the lines on the clock\\ndial are seen with equal clearness.\\nR. V. 1^ If W. 2.75 D.s.\\nL.V. :|^W. +3.75D.S.\\nReads Jaeger No. 1 at 6 inches.", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0066.jp2"}, "67": {"fulltext": "ILLUSTRATIVE CASES 49\\nOphthalmoscope. H. 3D. right H. 4 D. left, with normal\\nfundi.\\nIt will be observed in the above case that although the\\nophthalmometer showed corneal astigmatism of half a diopter\\nwith the rule, axis 90\u00c2\u00b0+ or 180\u00c2\u00b0\u00e2\u0080\u0094, that the patient did not\\naccept any cylindrical glass.\\nFollowing the rule laid down by Javal, and since confirmed\\nby many observers, that when the instrument reads astigma-\\ntism with the rule .50 D. usually must be subtracted from\\nthe reading, it will be seen that no astigmatism is left for\\ncorrection in the above case. As fully explained, page 29, the\\nlenticular astigmatism (or the action of the lens in stich\\ncases is in the same meridian as the corneal astigmatism,\\namounts as a general thing to .50 D., and is of an opposite\\nkind! to the corneal; therefore it neutralizes the corneal\\nastigmatism just to that extent.\\nSometimes the lenticular astigmatism amounts to but .25\\nD., and sometimes it is entirely absent. Again, it may amount\\nto a whole diopter or a diopter and a half, and in very excep-\\ntional cases to even more. So constant, however, is the len-\\nticular astigmatism of .50 D., that, when we find that the\\npatient does not accept the cylindrical glass as indicated by\\nthe ophthalmometer to within .50 D., it is well to take a\\nsecond, a third, and even a fourth reading with the instrument,\\nto see if we have not really made an incorrect reading.\\nFrom my own experience I would say that the lenticular\\nastigmatism generally amounts to just .50 D., next to this to\\n.25 D., next to this .75 D., and next to this 1 D.\\nCase TV. Corneal astigmatism with the rule^ .25 i)., neii-\\ntralized hy the lenticular astigmatism-; Patient accepts simple\\nspherical glasses. I. W. S., aged twenty years, general health\\n1 That is, if the horizontal meridian of the cornea is less curveei by .50 D.\\nthan the vertical meridian, then the horizontal meridian of the lens is more\\ncurved by .50 D. than the vertical meridian.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0067.jp2"}, "68": {"fulltext": "50 THE REFRACTION OF THE EYE\\nfirst class. He is a hard student his eyes ache and the vision\\nblurs in the afternoon and evening.\\nOphthalmometer. Astigmatism with the rule, .25 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 in each eye.\\nTest cards and trial lenses.\\nR.V. =f^:ff W. .50D.S.\\nL. V. =|^:|f W. +.50D.S.\\nReads Jaeger No. 1 at 6 inches.\\nOphthalmoscope. Hypermetropia 1 D. each.\\nAs this patient was from a neighboring state and had to\\nreturn, I ordered glasses after one test, +.50 D.s, for each eye.\\nThey relieved his headaches and painful vision, and he was\\nable to finish his schooling.\\nIn this case the corneal astigmatism of .25 D. was exactly\\nneutralized by a lenticular astigmatism of .25 D. the lenticular\\nnot amounting to its usual .50 D., in which case it would have\\nover-neutralized the corneal astigmatism of .25 D.\\nCase V. Corneal astigmatism with the rule^ .25 i)., with no\\nlenticular astigmatism. Sometimes the patient accepts the\\nexact amount of astigmatism indicated by the ophthalmometer,\\neven Avhen the astigmatism is with the rule. This shows that\\nin some instances there is no lenticular astigmatism at all, but\\nonly corneal. The present case illustrates this.\\nMarch 2, 1892, Catharine H., aged twenty years, is in good\\nhealth, but her eyes have been weak since a child; she has had\\nmany styes, and the eyelids are red most of the time. There is\\na well-marked blepharitis marginalis now. Typical asthenopia.\\nOphthalmometer. Astigmatism with the rule, .25 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 in each eye.\\nTest cards and trial lenses.\\nR. V. ff ff W. .25 D. cyl., 90\u00c2\u00b0.\\nL. V. ff ff W. -f .25 D. cyl., 90\u00c2\u00b0.\\nReads Jaeger No. 1 at 4 inches.", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0068.jp2"}, "69": {"fulltext": "ILLUSTRATIVE CASES 51\\nOphthalmoscope. Hypermetropia .50 D. each.\\nA solution of boracic acid was given to cleanse the eye with\\ntwice a day, and a weak ointment of yellow oxide of mercury\\nto rub on the lids at night, although she stated that she had\\nused this same ointment before without effect.\\nTwo days after, she was tested a second time and accepted\\nthe same glass as on the first test. The lids were in about the\\nsame condition as when first seen. A plus .25 D. cylindrical\\nglass, axis 90\u00c2\u00b0, was ordered for each eye. With these glasses\\nthe redness of the lids were entirely relieved, the styes ceased\\nto return, and she used her eyes with comfort.\\nWhile this case is reported primarily to show that there\\nmay be only corneal astigmatism present, and in a very small\\namount, it incidentally shows the value of very weak cylindri-\\ncal glasses in some cases. It is well known that weak cylin-\\ndrical glasses (.25 D.), when worn against the rule or at slanting\\naxis, often give marked relief, but they sometimes are of great\\nbenefit when worn with the rule and at symmetrical axis, as\\nshown in the present case.\\nThe ophthalmometer is of the greatest service in fitting\\ncorrectly such cases.\\nCase VI. Qomeal astigmatism ivith the rule, .50 i)., with\\nno lenticular astigmc^ism. December, 1896, Ruth M., aged\\ntwenty-six, is in robust health, but the eyes pain and the\\nvision blurs when she sews or reads for a little time.\\nOphthalmometer. Astigmatism with the rule, .50 D., axis\\n90\u00c2\u00b0 4- or 180\u00c2\u00b0 in each eye.\\nTest cards and trial lenses.\\nR. V. 1^ ff W. -f- .50 D. cyl., 90\u00c2\u00b0.\\nL. v. =|^:ffW. -f.50D. cyl.,90\u00c2\u00b0.\\nReads Jaeger No. 1 at 7 inches.\\nOphthalmoscope. Emmetropia in the vertical meridian,\\nand hypermetropia of .50 D. in the horizontal meridian.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0069.jp2"}, "70": {"fulltext": "52 THE REFRACTION OF THE EYE\\nOn a second test the same glass was accepted and prescribed,\\nwhich gave satisfaction.\\nCase VII. Corneal astigmatism with the rule, 1 D. right\\neye and .75 B. left eye No lenticular astigmatism. G. W. G.,\\naged thirty-five years, general health good. He has worn\\nglasses for four or five years, but not with comfort. Styes\\nhave troubled him from time to time also in the last four years.\\nOphthalmometer. Astigmatism with the rule, 1 D., 105\u00c2\u00b0\\n10\u00c2\u00b0 right eye .75 D., 75\u00c2\u00b0 or 165\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nR- H M W. .75 D. cyl., 105\u00c2\u00b0.\\nL. V. 1^: 1^ W. .75 D. cyl., 75\u00c2\u00b0.\\nReads Jaeger No. 1 at 7 inches.\\nOphthalmoscope. Simple hypermetropic astigmatism with\\nthe rule, 1 D. each, axis 105\u00c2\u00b0 right and 75\u00c2\u00b0 left.\\nSecond test the ophthalmometer showed the same reading,\\nthe axis in the right eye being two or three degrees nearer to\\nthe vertical meridian perhaps.\\nTest cards and trial lenses.\\nR.\\nV.\\nu\\nu\\nw.\\n1D.\\ncyl.,\\n105\u00c2\u00b0.\\nL.\\nV.\\n1*\\nu\\nw.\\n.75 D. cyl\\n,75\u00c2\u00b0\\nThis last glass was ordered, but in about three months time\\nthe axis of the right glass had to be shifted from 105\u00c2\u00b0 to 100\u00c2\u00b0,\\na distance of 5\u00c2\u00b0, when the glasses gave perfect comfort, and\\ncontinued to do so for the next few months that the patient\\nwas under observation.\\nCase VIII. Corneal astigmatism with the rule, 1 Z with\\nno lenticular astigmatism; Presbyopia. Mrs. T. R., aged\\nfifty-three, in moderately good health. She began to wear\\nglasses seven years ago, but they have never given her com-\\nfort, her eyes paining her when she sews or reads.", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0070.jp2"}, "71": {"fulltext": "i\\nILLUSTRATIVE CASES\\nOphthalmometer. Astigmatism with the rule,\\n90\u00c2\u00b0 or 180\u00c2\u00b0 in each eye.\\nTest cai ds and trial lenses.\\n1 D.\\n53\\naxis\\ni^- H ff W- 1 i^- cyh, 90\u00c2\u00b0.\\nL. V. IM^ W. 1 D. cyl., 90\u00c2\u00b0.\\nReads Jaeger No. 1 at 8 inches with 3 D. spherical\\nglass added for the presbyopia. 3 D.s 1 D. cyl., 90\u00c2\u00b0 was\\nordered for each eye for reading. These glasses have given\\nher entire satisfaction for almost three years.\\nThe last four cases reported are somewhat out of the ordi-\\nnary, because of the absence of lenticular astigmatism. Fur-\\nthermore, they serve to show the necessity of testing for any\\nastigmatism that the ophthalmometer indicates, for it may be the\\nonly form of astigmatism present.\\nCase IX. Hypermetropic astigmatism against the rule^ 1 D.\\nright ege, .75 D. left eye Patient accepts .50 D. more than the in-\\nstrument reads. L. M.,i aged thirty-nine, general health good.\\nHer eyes have not given her\\nany special trouble until the\\nlast year, when they began\\nto pain her and the vision to\\nblur when she read or sewed\\nfor any great length of time.\\nAt night she had to give up\\nclose work and reading.\\nOphthalmometer. Astig-\\nmatism against the rule, ID.,\\naxis 180\u00c2\u00b0 -F or 90\u00c2\u00b0 right\\neye; .75 D., axis 180\u00c2\u00b0 or\\n90\u00c2\u00b0 -left eye.\\nFigure 26 is a diagram-\\nmatic section of such an eye showing where the rays of light\\n1 Reported from Drs. Lewis and Van Fleet s clinic.\\nJ 80\\nFig. 26.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0071.jp2"}, "72": {"fulltext": "54 THE REFRACTION OF THE EYE\\nfocus respectively in the vertical and horizontal meridians.\\nThe horizontal meridian is emmetropic and focusses rays on\\nthe retina while the vertical meridian is hypermetropic, less\\ncurved than the horizontal, and allows the rays of light to\\nfocus back of the retina.\\nTest cards and trial lenses. The vertical lines on the\\nGreen s clock-dial are seen plainest.\\nR. V. f^ fj W. 1.50 D. cyl., 180\u00c2\u00b0.\\nL. V. 1^ f^ W. 1.25 D. cyh, 180\u00c2\u00b0.\\nOphthalmoscope. Simple hypermetropic astigmatism against\\nthe rule.\\nOn a second test the same glasses were accepted by the\\npatient and were ordered. The above glasses have been worn\\nfor three years with perfect satisfaction. Usually in cases of\\nastigmatism against the rule we add .50 D. to the reading of\\nthe instrument. However, it may be more or less, as illus-\\ntrated by some of the following cases. Furthermore, in the\\ncases of astigmatism against the rule must be reckoned those\\nw^here there is no corneal astigmatism at all, for in such cases\\nthere is usually a small amount of lenticular astigmatism\\nagainst the rule which must be corrected.\\nCase X. Corneal astigmatism against the rule The patient\\naccepts only .25 D. more than the instrume^it reads. Lawrence\\nM., aged eleven, was seen at the clinic on February 2, 1897.\\nIs in good health, family history good father died aged forty,\\nfrom accident, mother living, aged thirty-three, one sister older\\nand two brothers younger living none ever wore glasses.\\nOphthalmometer. Astigmatism against the rule, .25 D.,\\naxis 180\u00c2\u00b0 or 90\u00c2\u00b0 in each eye.\\nTest cards and trial lenses.\\nR. V. 11 ff W. .50 D. cyl., 180\u00c2\u00b0.\\nL. V. f-l ff W. .50 D. cyl., 180\u00c2\u00b0.", "height": "4245", "width": "2698", "jp2-path": "refractionofeye00davi_0072.jp2"}, "73": {"fulltext": "ILLUSTRATIVE CASES 55\\nReads Jaeger No. 1 at 6 inches.\\nOphthalmoscope. Hypermetropia 1 diopter in each eye.\\nA mild astringent wash was ordered for the lids, which\\nwere somewhat inflamed. On a second test, one week later, the\\npatient accepted the same glass as at first. Ordered .50 D.\\ncyl. 180\u00c2\u00b0 each eye. September, 1897, the glasses were still\\nsatisfactory.\\nCase XI. Ophthalmometer shoivs corneal astigmatism against\\nthe rule., and the patient accepts .75 D. more than the instrument\\nreads. Abbie P., aged forty-six, came to the clinic on Decem-\\nber 27, 1892. Has worn glasses for the last six years, but none\\nof them have been satisfactory. She is in fairly good health.\\nOphthalmometer. Astigmatism against the rule, .25 D.,\\naxis 180\u00c2\u00b0 or 90\u00c2\u00b0 in each eye.\\nTest cards and trial lenses.\\nR. V. f 1^ W. 1 D. cyl., 180\u00c2\u00b0.\\nL. V. 1^ 1^ 4- W. 1 D. cyl., 180\u00c2\u00b0.\\nReads Jaeger No. 1 at 10 inches with a 3 D. added for\\npresbyopia, which is a big amount considering the age of the\\npatient, only forty-six years.\\nOphthalmoscope. Hypermetropic astigmatism.\\nTwo days later a second test gave the same result as the\\nprevious one. Ordered -f- 1 D. cyl., 180\u00c2\u00b0 each eye, for dis-\\ntance and -J-3D.S added for reading. The same strength\\ncylindrical glasses have been worn since, but the spherical part\\nhas been increased for the increasing presbyopia.\\nCase XII. Ophthalmometer shoivs astigmatism against the\\nrule; The patient accepts the reading of the instrument exactly\\nin one eye., hut .25 D. less than the reading of the instrument\\nin the other though the astigmatism is against tlie rule. S. H.\\nW., aged thirty-six, in robust health, consulted me February 5,\\n1894, on account of painful vision. His eyes have troublecj\\nhim more or less for over a year, especially for close work.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0073.jp2"}, "74": {"fulltext": "^Q THE REFRACTION OF THE EYE\\nOphthalmometer. Astigmatism against the rule, 1.50 D.,\\naxis 180\u00c2\u00b0 -I- or 90\u00c2\u00b0 right eye .75 D., axis 180\u00c2\u00b0 or 90\u00c2\u00b0\\nleft eye.\\nTest cards and trial lenses.\\nR. V. 3-% L f^ W. 1.50 D. cyl., 180\u00c2\u00b0.\\nL-V. 1^ :|^W. .75 D. cyl., 180\u00c2\u00b0.\\nReads Jaeger No. 1 at 5 inches.\\nOphthalmoscope. Hypermetropic astigmatism against the\\nrule, 1 D. each eye.\\nOn a second test the ophthalmometer gave the same reading,\\nand the patient accepted exactly the same glass in the right\\neye, but a .25 D. weaker glass in the left eye. Ordered\\n1.50 D. cyl., 180\u00c2\u00b0 right eye\\n.50 D. cyl., 180\u00c2\u00b0 left eye.\\nMay, 1896, over two years after they were ordered, the\\nglasses were still giving entire satisfaction.\\nCase XIII. No corneal astigmatism^ hut the patient accepts\\na .50 D. cylindrical glass against the rule., at 180\u00c2\u00b0. C. C.\\nD., aged forty-two years, general health is good. He consulted\\nan eminent oculist ten years ago, who told him that he had no\\nrefractive error his eyes continued to trouble him more or\\nless all the time. Nine months ago he had spherical glasses\\nfitted on account of presbyopia, but they have been unsatis-\\nfactory. He consulted me first in February, 1893, when the\\nfollowing condition of affairs was found\\nOphthalmometer. Shows no corneal astigmatism, that is, the\\nimages of the mires neither overlap nor separate at any position\\nafter they have once been approximated, and the black lines\\ndividing them into halves remain opposite and straight in all\\npositions.\\nIn such cases it is usual for the patient to have lenticular", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0074.jp2"}, "75": {"fulltext": "ILLUSTRATIVE CASES\\n57\\nastigmatism of about .50 D. against the rule, that is to say, if\\nthe eye is hypermetropic that a plus cylindrical glass will be\\nworn with its axis at 180\u00c2\u00b0, or in that neighborhood, while if\\nmyopic a minus cylindrical glass will be worn at 90\u00c2\u00b0, or in\\nthat neighborhood.\\nA and B in Fig. 27 show the shape of the cornea and lens\\nrespectively, and focuses of the two chief meridians combined in\\nthe present case. A shows both meridians of the cornea to\\nFig. 27.\\nhave the same radius of curvature, therefore the cornea to be\\nspherical in shape. It is emmetropic in refractive power in\\nthis case.\\nThe lens (5, Fig. 27) is emmetropic in refractive power in\\nthe horizontal meridian also, but in the vertical meridian it is\\nhypermetropic by .50 D.\\nAs both the cornea and the lens are emmetropic in the\\nhorizontal meridian, it allows the rays of light that pass through\\nthat meridian to focus exactly on the retina. The cornea is\\nemmetropic in the vertical meridian also, but the lens is hyper-\\nmetropic .50 D., and consequently the rays of light that pass", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0075.jp2"}, "76": {"fulltext": "58 THE REFRACTION OF THE EYE\\nthrough that meridian focus behind the retina. It requires a\\ncylindrical glass of .50 D., axis 180\u00c2\u00b0, to focus these rays of\\nlight on the retina and a plus cylindrical glass worn with its\\naxis at 180\u00c2\u00b0 shows the astigmatism to be against the rule.\\nTest cards and trial lenses.\\nR. y. |o _ 1| W. -f- .50 D. cyl., 180\u00c2\u00b0.\\nL. Y. fl W. .50 D. cyl., 180\u00c2\u00b0.\\nReads Jaeger No. 1 at 7 inches with a .75 D. spherical\\nglass added to correct the presbyopia.\\nOphthalmoscope. Hypermetropic astigmatism .50 D. against\\nthe rule.\\nOrdered .75 D. .50 D. cyl., 180\u00c2\u00b0 each. May, 1895, two\\nyears later, the glasses are still satisfactory.\\nIn such cases as the above, and especially in presbyopes, the\\nretinoscope is of value in confirming the subjective tests. In\\nyoung subjects, however, to make the retinoscopic tests reliable\\natropine or some mydriatic must be used, which fact impairs\\nits usefulness very much. Fortunately it is seldom necessary\\nto use mydriatics of any kind, and in my practice retinoscopy,\\nor more correctly speaking, skiascopy., plays a very unimportant\\nrole.\\nCase XIV. No corneal astigmatism. TKe patient accepts\\ncylindrical glasses against the rule at different axes, 180\u00c2\u00b0 and 135\u00c2\u00b0\\nrespectively. N. Y., aged fourteen years, general health first-\\nclass, consulted me April 1, 1896. For three months her eyes\\nhave troubled her greatly, and especially after studying her\\nlessons. Blurring of the vision, pain in the eyes, and headaches\\nare the chief symptoms she complains of. She has an older\\nsister who has mixed astigmatism.\\nOphthalmometer. No corneal astigmatism.\\nRetinoscope. Hypermetropic astigmatism of small amount\\n(.50 D.) in each eye, axis of cylindrical glass 180\u00c2\u00b0 Rt., and at\\n135\u00c2\u00b0 Lft.", "height": "4247", "width": "2698", "jp2-path": "refractionofeye00davi_0076.jp2"}, "77": {"fulltext": "ILLUSTRATIVE CASES\\n59\\nTest cards and trial lenses. The vertical lines from XII to\\nVI in the clock-dial are seen plainest in the right eye, while the\\nlines from X to IV and XI to V are seen plainest with the left\\neye.\\nR V 2-^\\nJX. V 20\\nL. V.\\n:ff W. .50D. cyl.,180\u00c2\u00b0.\\n|o _ 10 w. .50 D. cyL, 135\u00c2\u00b0.\\nReads Jaeger No. 1 at 3 inches.\\nOphthalmoscope. Hypermetropic astigmatism of small\\namount, but could not be estimated accurately.\\nFigures 27 and 28 show the form of the cornea and the foci\\nof the chief meridians in the right and left eyes respectively.\\nOn account of a mild\\nconjunctivitis, an astrin-\\ngent wash for the eyes was\\nordered, and the patient re-\\nquested to come again in\\none week. A mydriatic was\\nordered to be used for three\\ndays before coming for the\\nsecond test. The second\\ntest corresponded with the\\nfirst as to the amount and\\naxis of the astigmatism, but\\nthe patient accepted 75\\nD. spherical glasses in ad-\\ndition to the cylinders. The\\nophthalmoscope and retinoscope showed compound hyperme-\\ntropic astigmatism. Ordered:\\n-K .50 D. cyl., 180\u00c2\u00b0, right eye\\n.50 D. cyl., 135\u00c2\u00b0, left eye.\\nOne year later, April, 1897, the glasses were still entirely\\nsatisfactory.\\nFig. 28. Astigmatism against the rule,\\nwith the axes at 45\u00c2\u00b0 and 135\u00c2\u00b0 (left eye)", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0077.jp2"}, "78": {"fulltext": "60 THE REFRACTIOX OF THE EYE\\nCase XV. Ophthalmoineter shows no corneal astigmatism\\nPatient accepts a -f .25 D. cylindrical glass agamst the rule, axis\\n180\u00c2\u00b0 in each eye. Mary T., aged forty, came to the clinic\\nMarch 10, 1895, for glasses for reading and sewing. The pa-\\ntient is in good health.\\nOphthalmometer. No corneal astigmatism whatever, the\\nlines dividing the mires being straight with each other in all\\nmeridians, and the images neither overlapping nor separating\\nafter once being approximated.\\nRetinoscopy was unsatisfactory, both as to the axis and the\\namount of the astigmatism, and even as to the kind.\\nTest cards and trial lenses.\\nU -U W- -25 D. cyl., 180^\\nL. Y. f\u00c2\u00a7 1^ W. .25 D. cyl., 180\u00c2\u00b0.\\nReads Jaeger No. 1 at 10 inches with a 1 D. spherical\\nglass added.\\nOphthalmoscope. Emmetropic in each eye, apparently.\\nThe patient has a lachrymal catarrh, for which she was treated\\nfor three weeks before a second test was made.\\nSecond test The ophthalmometer gave the same reading\\nand the patient accepted the same glass as on the first test.\\nOrdered 1 D.s .25 D. cyl., 180\u00c2\u00b0 for each eye for reading.\\nCase XVI. Ophthalmometer shows no corneal astigmatism\\nThe patient accepts .15 D. cylindrical glass against the rule.,\\naxis 180\u00c2\u00b0 in each eye. R. H. U., aged twenty-one, student,\\nconsulted me September 5, 1G93. The patient is in good health,\\nbut somewhat run down from hard study. He complains of\\npain in the eyes, blurring of vision after long work, and also\\nof a slight discharge from, and stiffness of, the lids.\\nOphthalmometer No corneal astigmatism.\\nRetinoscope. .50 D. astigmatism against the rule, with the\\nchief axes at 180\u00c2\u00b0 and 90\u00c2\u00b0", "height": "4262", "width": "2698", "jp2-path": "refractionofeye00davi_0078.jp2"}, "79": {"fulltext": "ILLUSTRATIVE CASES 61\\nTest cards and trial lenses.\\nR. V. 1^ 1^ W. .50 D. cyl., 180^\\nL. V. |g 1^ W. .50 D. cyl., 180\u00c2\u00b0.\\nReads Jaeger No. 1 at 5 inches.\\nA mild astringent wash was prescribed for the conjuncti-\\nT itis. One week later a second test was made, the ophthal-\\nmometer still read negative, but the patient accepted .75 D.\\ncylindrical glass, axis 180\u00c2\u00b0, over each eye, which was ordered.\\nThree years later these glasses were still satisfactory, but at\\ntimes the patient was troubled with conjunctivitis and a slight\\ndischarge from the lids.\\nCase XVII. No corneal and no lenticular astigmatism^ a\\nmoderate amount of latent hypermetropia. Miss R. G. L., aged\\ntwenty-three, consulted me October 24, 1896. She is in good\\nhealth, but overworked in a School of Applied Design,\\nwhere she is trying to take a two years course in one year s\\ntime, and as a consequence has overtaxed her eyes with fine\\ndrawing. For the past two weeks the left eye especially has\\npained her after working all day.\\nOphthalmometer. No corneal astigmatism whatever.\\nTest cards and trial lenses.\\nR. V. 11^ not improved with any glass.\\nL. y not improved with any glass.\\nReads Jaeger No. 1 from 3|- to 20 inches.\\nOphthalmoscope. Hypermetropia 1.25 D. both.\\nNo muscular insufficiencies present.\\nThis patient was ordered to discontinue some of her work,\\nwas put on tonics, and in a few weeks time had no further\\ntrouble.\\nContrary to the above case (that is, no corneal astigma-", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0079.jp2"}, "80": {"fulltext": "62 THE REFRACTION OF THE EYE\\ntism), we usually have .50 D. of lenticular astigmatism against\\nthe rule when there is no corneal astigmatism present.\\nCase XVIII. Astigmatism with the rule^ .25 D.^ axis 90\u00c2\u00b0 -f-\\n(?rl80\u00c2\u00b0\u00e2\u0080\u0094 according to the ophthalmometer; Patient accepts a\\n.25D. cylindrical glass., axis 180\u00c2\u00b0, against the rule. Annie\\nD., aged twenty-scTen, in good health. She came to the clinic\\nat the Manhattan Eye and Ear Hospital on account of her eyes\\nhurting when she did close work.\\nOphthalmometer. Astigmatism with the rule, .25 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 in each eye.\\nTest cards and trial lenses.\\nR. V. 1^ ff W. .25 D. cyl., 180^\\nL. V. 1^ ff W. .25 D. cyl., 180\u00c2\u00b0.\\nReads Jaeger No. 1 at 6 inches.\\nThe test with the lines on the clock-dial was unsatisfactory^\\nas was also retinoscopy.\\nOphthalmometer. Hypermetropia .50 D. each eye.\\nA second test two days later gave the same result, and -f 25\\nD. cylindrical glass, axis 180\u00c2\u00b0, was ordered for each eye. These\\nglasses have given satisfaction for over a year.\\nA second case similar to the above, that is, the patient\\naccepting .25 D. cylindrical glass against the rule (180\u00c2\u00b0) when\\nthe ophthalmometer reads astigmatism with the rule .25 D., is\\nfurnished me b}^ Dr. Van Fleet from his private practice and\\nI take this opportunity to express my thanks to him. I give\\nthe case as he reported it, with his remarks.\\nCase XIX. Corneal astigmatism with the rule, .25 D.\\nPatient accepts .25 cylindrical glass against the rule and is\\nrelieved of a marked asthenopia., with marked improvement in\\nvision. Miss P., aged nineteen years, has suffered for some\\ntime with headache, dizziness, occasional diplopia, and attacks of\\nmomentary blindness. In November, 1896, while looking out", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0080.jp2"}, "81": {"fulltext": "ILLUSTRATIVE CASES 63\\nof a window at a passing parade everything suddenly appeared\\nblack to her, and she called to her sister who was in the room\\nwith her that she could not see. She felt sick and faint, and\\nher family became alarmed and sent for the family physician,\\nwho responded at once, but by the time he arrived the attack\\nhad passed away.\\nThe physician, fearing some kidney trouble, examined his\\npatient very carefully, but was unable to discover anything\\nabnormal about her. During the two weeks he observed her\\nshe had several of these attacks, and finally concluding her\\neyes must be at fault, he referred her to me for examination.\\nDecember 2, 1896. Patient is a large, healthy looking\\nyoung woman, giving history as above.\\nPupils normal and react properly. No apparent deviation\\nof visual lines.\\nOphthalmometer. 0.25 D. with the rule.\\nOphthalmoscope, about emmetropic.\\nVision, both eyes with 0.25 D. cyl. ax. 180\u00c2\u00b0.\\nReads J. 1 with and without this glass and has good range\\nof accommodation.\\nOrdered 0.25 D. cyl. ax. 180\u00c2\u00b0 constant.\\nApril 1, 1897. Physician reports that the patient is en-\\ntirely free from all the asthenopic symptoms she formerly had.\\n\u00e2\u0080\u00a2Remarks. The history is peculiar for two reasons first,\\nit \\\\s unusual for such marked symptoms to result from so small\\na refractive error and second, it is unusual to have so great a\\ndiminution in vision made perfect with so weak a plus glass.\\nIt exemplifies also the value of Javal ophthalmometer and\\nthe almost constant relation between the amounts of corneal\\nand lenticular astigmatism.\\nOne half diopter of corneal astigmatism with the rule\\nbeing normal necessitates the existence of one half diopter of\\nlenticular astigmatism against the rule.\\nThe existence of one diopter with the rule in the cornea", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0081.jp2"}, "82": {"fulltext": "64 THE REFRACTION OF THE EYE\\nindicates an excess of one half diopter which must be corrected.\\nObversely, a total absence of corneal astigmatism leaves un-\\ncorrected one half diopter lenticular astigmatism, necessitating\\na glass of one half diopter against the rule.\\nTherefore a quarter diopter of corneal astigmatism with\\nthe rule will correct one-half the normal lenticular astigmatism,\\nnecessitating one quarter diopter against the rule for complete\\ncorrection.\\nThe chief thing of interest in these last two cases, from the\\npoint of view of the ophthalmometer, is that the patients should\\nwear a .25 D. cylindrical glass against the rule when the\\ninstruments reads .25 D. astigmatism with the rule. Its ex-\\nplanation is easy, if we only keep in mind the rule to deduct\\n.50 D. from the reading of the instrument when the astig-\\nmatism is with the rule. In the above cases there is only\\n.25 D. of corneal astigmatism, consequently if the lenticular\\nastigmatism is of the usual amount (.50 D.), it will not only\\nneutralize the .25 D. of corneal astigmatism, but leave .25 D.\\nof its own, or lenticular, astigmatism to be corrected. But\\nwhy does this remaining .25 D. of lenticular astigmatism re-\\nquire the cylindrical glass to be worn against the rule This\\ncan be explained better by diagrams than in any other way.\\nFig. 29, shows the cornea, front view, and the points where\\nthe rays of light passing through its two chief meridians would\\nfocus if no lenticular astigmatism was present B shows the\\nlens, front view, and where the rays of light would focus after\\npassing through its two chief meridians if no corneal astig-\\nmatism was present and C represents a composite of the two as\\nthey actually are and the points where rays of light focus after\\npassing through the two chief meridians of each.\\nThe horizontal meridians of both the cornea and the lens in\\nthe above cases are emmetropic, as seen by the diagrams, and\\nallow the rays of light to focus on the retina. The vertical\\nmeridian of the cornea is more curved by .25 D. than its", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0082.jp2"}, "83": {"fulltext": "VARIATION IN AXIS OF THE ASTIGMATISM\\n65\\nhorizontal meridian. This is demonstrated by the overlapping\\nof the images of the mires to the extent of .25 D. when they\\nare turned from the horizontal to the vertical meridian after\\nhaving been approximated. But the vertical meridian of the\\nlens is too little curved by .50 D. It therefore neutralizes the\\n.25 D. of corneal astigmatism (which is with the rule) and\\nleaves still .25 D. lenticular astigmatism against the rule in the\\nvertical meridian to be corrected, which requires .25 D.\\ncylindrical glass axis 180\u00c2\u00b0.\\n180\\nCORNEA\\nFig. 29. A shows the focuses of the two chief meridians of the cornea, assuming no\\nlenticular astigmatism; B, the focuses of the two chief meridians of the lens,\\nassuming no corneal astigmatism C, the focuses of their combined action, with\\n.25 D. corneal astigmatism with the rule and .50 D. of lenticular astigmatism\\nagainst the rule.\\nOases showing the variation of axes of the chief meridians of\\ncurvature of the cornea from 90\u00c2\u00b0 a7id 1S0\u00c2\u00b0. The plurality of\\ncases of astigmatism have their chief meridians exactl}^ at 90\u00c2\u00b0\\nand 180\u00c2\u00b0, and, as a rale, the meridian that has a shorter radius\\nof curvature is at 90\u00c2\u00b0, while the meridian that has the longer\\nradius of curvature is at 180\u00c2\u00b0. Many times the two chief\\nmeridians are not exactly at 90\u00c2\u00b0, but vary and this variation\\nin the majority of cases is symmetrical in character. That is,\\n1 Clairborne, JV. Y. Med. Jour. June 25, and July 2, 1892. See also refer-\\nence on page 200.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0083.jp2"}, "84": {"fulltext": "66\\nTHE REFRACTION OF THE EYE\\nR. E.\\nL. E,\\nFig. 30.\\nin cases of astigmatism with the rule, the shorter curved merid-\\nians slant the same number of degrees to the temporal, or nasal,\\nside of 90\u00c2\u00b0 in each\\neye, while the longer\\ncurved meridians re-\\nmain at right angles\\nto the shorter curved\\nmeridians. For exam-\\nple, if the shorter\\ncurved meridian in the right eye is at 75\u00c2\u00b0, that is 15\u00c2\u00b0 to the\\nnasal side of 90\u00c2\u00b0, the shorter curved meridian in the left eye is\\nat 105\u00c2\u00b0, or also 15\u00c2\u00b0 to the nasal side of 90\u00c2\u00b0. In other words,\\nboth axes slant inward to the extent of 15\u00c2\u00b0 (see Fig. 30).\\nOn the contrary, usually, if the shorter curved meridian in\\nthe right eye slants toward the temple 30\u00c2\u00b0, the shorter meridian\\nin the left eye slants toward\\nthe temple 30\u00c2\u00b0. In such a\\ncase, the axis in the right eye\\nwould be at 120\u00c2\u00b0 and in the\\nleft eve at 60\u00c2\u00b0, with the\\neye\\nlonger curved meridians re-\\nR. E.\\nL. E.\\nFig. 31.\\nspectively at right angles (see\\nFig. 31). In such a case, if the patient was hypermetropic,\\nplus cylinders would be worn at 120\u00c2\u00b0 and 60\u00c2\u00b0 if myopic,\\nminus cylinders at 30\u00c2\u00b0 and 150\u00c2\u00b0.\\nThere are a number of exceptions to this rule, however.\\nFor instance, the meridian of shorter radius of curvature may\\nslant but 10\u00c2\u00b0 to the temporal side of the vertical meridian in\\none eye and 15\u00c2\u00b0 to the temporal side in the other, etc. Or,\\nagain, the two chief meridians of curvature may be exactly at\\n90\u00c2\u00b0 and 180\u00c2\u00b0 in one eye, while the chief meridians may be\\nslanting in the opposite eye and so on.\\nAt rare intervals, the shorter curved meridian in each eye\\nmay slant in the same direction from the vertical meridian, that", "height": "4260", "width": "2698", "jp2-path": "refractionofeye00davi_0084.jp2"}, "85": {"fulltext": "ILLUSTRATIVE CASES\\n61\\n135\\nis, to the temple in one eye and to the nose in the other. For\\nexample, both of the shorter curved meridians may be at 75\u00c2\u00b0\\n(see Fig. 32).\\nIn astigmatism against the rule the longer curved meridian\\nis at 90\u00c2\u00b0 or its neighborhood, and is subject to the same variations\\nas in the case of astigma-\\ntism with the rule. les/^ X les\\nIn exceptional cases,\\nthe two chief meridians\\nof curvature stand ex- R- E. L. E.\\nFtp S9\\nactly at 45\u00c2\u00b0 and 135\u00c2\u00b0. If\\nthis happens in both eyes, the meridian of the shorter radius of\\ncurvature is usually at 45\u00c2\u00b0 in one eye and at 135\u00c2\u00b0 in the other.\\nThe symmetry of the eyes, as\\nindicated in the beginning of\\n,:this section, is thus carried out.\\nFor each shorter meridian in\\nL. E. this instance would slant the\\nsame number of degrees from\\nthe vertical, and both either toward the temples, or both\\ntoward the nose (see Fig. 33).\\nIn all of these cases, the ophthalmometer is of inestimable\\nvalue in finding the axes, and no method compares with it for\\naccuracy and facility.\\nCase XX. Both axes slant 30\u00c2\u00b0 to the nasal side of the\\nvertical meridian^ standing at 60\u00c2\u00b0 in the right eye and at 120\u00c2\u00b0 in\\nthe left eye. Agnes R., aged twenty-seven, consulted me\\nJuly 9, 1895. She had worn glasses for a year, but without\\nrelief of her eye symptoms, which were pain, blurring of\\nvision, headaches, etc., in fact, typical asthenopia.\\nOphthalmometer. Astigmatism with the rule, ID., axis\\n60\u00c2\u00b0 or 150\u00c2\u00b0 right eye 1 D., axis 120\u00c2\u00b0 -f- or 30\u00c2\u00b0 left eye.\\nIn the present case, in the right eye, the black lines dividing\\nthe mires were not straight at 0\u00c2\u00b0, but were at 150\u00c2\u00b0, and that\\nFig. 33.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0085.jp2"}, "86": {"fulltext": "68\\nTHE REFRACTION OF THE EYE\\nwas the starting point or primary position. The mires were\\napproximated, and the long indicator turned at right angles ta\\nthe primary position or to 60\u00c2\u00b0, where they overlapped one step.\\nThis was, therefore, astigmatism 1 D. with the rule, axis 60\u00c2\u00b0\\nor 150\u00c2\u00b0-.\\nIn the left eye the primary position was found at 30\u00c2\u00b0, and\\nthe secondary position at 120\u00c2\u00b0.\\nTest cards and trial lenses.\\n^\u00e2\u0080\u00a2^\u00e2\u0080\u00a2=M-MW. +.50D. cyL, 60\u00c2\u00b0.\\nL. V. II ff W. .50 D. cyl., 120\u00c2\u00b0.\\nReads Jaeger No. 1 at 6 inches.\\nOphthalmoscope. Hypermetropic astigmatism in each eye^\\n150\\nR. E.\\nFig. 34.\\nOn the second test the patient accepted the same glass as at\\nfirst. Ordered\\n.50 D. cyl., ax. .60\u00c2\u00b0 right;\\n-h.50D. cyL,ax. 120\u00c2\u00b0 left.\\nCase XXI. Both of the shorter axes slant 15\u00c2\u00b0 to the tem-\\nporal side of the vertical meridian., standing at 105\u00c2\u00b0 in the right", "height": "4262", "width": "2698", "jp2-path": "refractionofeye00davi_0086.jp2"}, "87": {"fulltext": "ILLUSTRATIVE CASES\\n69\\neye and at 75\u00c2\u00b0 in the left eye, Hannah M., aged thirty, con-\\nsulted me January 23, 1897. She complained that the eyelids\\nbecame red and swollen at times, and of frontal headaches and\\npains in the eyeballs. Her general health is good.\\nOphthalmometer. Astigmatism with the rule, 1 D., 105\u00c2\u00b0\\nor 15\u00c2\u00b0 right eye 1.50 D., 75\u00c2\u00b0 or 165\u00c2\u00b0 left eye.\\nR. E\\nFig. 35.\\nTest cards and trial lenses.\\nL.E,\\nI^-^-f*- -I^W. .50D. cyl.,105\u00c2\u00b0.\\nL.V.f-J-:|aW. +1 D. cyl., 75\u00c2\u00b0.\\nReads Jaeger No. 1 at 7 inches.\\nOphthalmoscope. Hypermetropic astigmatism with the rule.\\nA second test resulted the same as the first. Ordered\\n.50 D. cyl., 105\u00c2\u00b0 right eye\\n4-1 D. cyl., 75\u00c2\u00b0 left eye.\\nYellow oxide of mercury ointment was prescribed for the\\nredness of the edges of the lids.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0087.jp2"}, "88": {"fulltext": "70\\nTHE REFRACTION OF THE EYE\\nJune, 1897. The patient has worn the glasses with perfect\\ncomfort, and the blepharitis marginalis has been relieved.\\nCase XXII. Both axes slant hut 5\u00c2\u00b0 to the temporal side of\\nthe vertical meridian^ standing at 95\u00c2\u00b0 in the right eye and at 85\u00c2\u00b0\\nin the left eye. Miss F. J. O., aged twenty, consulted me\\nMarch 27, 1897. For two years she has been troubled by\\nshadows whirling around in front of her eyes. These shadows\\nare not constant, but appear at intervals and are annoying to\\nthe patient. She has no headache and no pain in the eyes.\\nR. E.\\nL. E.\\nFig. 36.\\nOphthalmometer. Astigmatism with the rule, 1.50 D., axis\\n95\u00c2\u00b0 or 5\u00c2\u00b0 right eye 1 D., axis 85\u00c2\u00b0 or 175\u00c2\u00b0 left eye.\\nThe primary position was found at 5\u00c2\u00b0 and the secondary at\\n95\u00c2\u00b0 in the right eye. The primary position was found at 175**\\nand the secondary at 85\u00c2\u00b0 in the left eye.\\nIt will be noticed that in most cases of astigmatism with\\noff axes, that is, with the axes away from 90\u00c2\u00b0 and 180\u00c2\u00b0, the\\nsecondary position can be obtained by adding 90\u00c2\u00b0 to the primary\\nposition when that is less than 90\u00c2\u00b0, and by subtracting 90\u00c2\u00b0 from", "height": "4251", "width": "2698", "jp2-path": "refractionofeye00davi_0088.jp2"}, "89": {"fulltext": "ILLUSTRATIVE CASES 71\\nthe primary position when it is less than 90\u00c2\u00b0. For instance, in\\nthis case the primary position in the right eye is at 5\u00c2\u00b0, add 90\u00c2\u00b0\\nto it, and we get 95\u00c2\u00b0, the secondary position. In the left eye\\nthe primary position is at 175\u00c2\u00b0, subtract 90\u00c2\u00b0 from it, and we get\\n85\u00c2\u00b0, the secondary position. This is true in all cases when the\\nchief meridians are at right angles to each other, and they\\nusually are.\\nTest cards and trial lenses.\\nR. y. 1^ 1^ W. 1 D. cyl., 95\u00c2\u00b0.\\nL. V. f J 20 w. 1 D. cyl., 85^\\nReads Jaeger No. 1 at 4 inches.\\nOphthalmoscope. Simple hypermetropic astigmatism with\\nthe rule.\\nMarch 30, three days later, the ophthalmometer reads the\\nsame\\nR. V. 1^ f W. 1 D. cyl., 95\u00c2\u00b0.\\nL. V. f^ 1^ W. .75 D. cyl., 85\u00c2\u00b0.\\nOrdered\\n1 D. cyl., 95\u00c2\u00b0 right;\\n.75D. cyL,85\u00c2\u00b0left.\\nTwo months later the glasses were satisfactory.\\nCase XXIII. Axis vertical or 90\u00c2\u00b0 in one eye^ and 15\u00c2\u00b0 from\\nthe vertical in the other eye., standing at 75\u00c2\u00b0. Robert I., aged\\nfifteen, consulted me October 12, 1895. He suffered from a\\ntypical asthenopia and a mild conjunctivitis. He is in good\\ngeneral health, but a close student.\\nOphthalmometer. Astigmatism with the rule 1 D., axis 75\u00c2\u00b0\\nor 165\u00c2\u00b0 right eye 2.50 D., axis 90\u00c2\u00b0 or 180\u00c2\u00b0 left eye.\\nThe primary position in the right eye was found at 165\u00c2\u00b0 and\\nthe secondary at 75\u00c2\u00b0. The primary position in the left eye was\\nfound at 0\u00c2\u00b0 or 180\u00c2\u00b0 and the secondary at 90\u00c2\u00b0.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0089.jp2"}, "90": {"fulltext": "72\\nTHE REFRACTION OF THE EYE\\n165\\nB,E.\\nL.E.\\nFig. 37.\\nTest cards and trial\\nR.Y. 2^_:|^W.+ .75D.,cyl.,75\u00c2\u00b0.\\nL. V. f^ 1^ W. 2 D., cyl., 90^\\nReads Jaeger No. 1 at 5 inches.\\nOphthalmoscope. Simple hypermetropic astigmatism with\\nthe rule in each eye.\\nA mild astringent wash was ordered for the conjunctivitis,\\nand the above glasses ordered\\n.T5D.,cyl., 75\u00c2\u00b0right;\\n2 D.,cyl.,90\u00c2\u00b0left.\\nMay 1, 1896, the glasses were still satisfactory.\\nCase XXIV. Both axes slant 15\u00c2\u00b0 in the same direction from\\nthe vertical meridian., to the temporal side in the right and to the\\nnasal side in the left., standing in each at 105\u00c2\u00b0. R. E. P.,\\naged thirty-seven, consulted me November 8, 1896, complaining\\nof frontal headaches and pains in the eyes after reading or", "height": "4264", "width": "2698", "jp2-path": "refractionofeye00davi_0090.jp2"}, "91": {"fulltext": "ILLUSTRATIVE CASES\\nT3\\nworking. His general health is not very good, is a business\\nman and overworked.\\nOphthalmometer. Astigmatism with the rule ID., axis\\n105\u00c2\u00b0 4- or 15\u00c2\u00b0 in each eye. The primary position in each\\ninstance was found at 15\u00c2\u00b0 and the secondary at 105\u00c2\u00b0.\\nTest cards and trial lenses.\\nR. Y. 1^ _ II W. -f- .50 D. cyl., 105\u00c2\u00b0.\\nL. V. 1^ ff W. .50 D. cyL, 105\u00c2\u00b0.\\nReads Jaeger No. 1 at\\nT inches.\\nOphthalmoscope. Sim-\\nple hypermetropic astig-\\nmatism in each eye.\\nOn a second test the\\npatient accepted the same\\nglasses as at first. Or-\\ndered .50 D. cyl., 105\u00c2\u00b0,\\neach eye. These glasses\\nhave continued to give\\ncomfort for six months,\\nMay 2, 1897, when the\\npatient was last heard\\nfrom.\\nCase XXV. Astigmatism against the rule ivhere the axes of\\nthe glasses slant relatively the same number of degrees from the\\nhorizontal meridian^ standing at 15\u00c2\u00b0 in one eye and at 165\u00c2\u00b0 in the\\nother eye. In hypermetropic astigmatism against the rule and\\nmyopic astigmatism with the rule, when the axes vary from 90\u00c2\u00b0\\nand 180\u00c2\u00b0, they usually slant the same number of degrees and\\nrelatively in the same direction from the horizontal meridian.\\nHowever, there are exceptions just as numerous as the varia-\\ntions noted in the cases of hypermetropic astigmatism with the\\nFig. 38.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0091.jp2"}, "92": {"fulltext": "74\\nTHE REFRACTIOX OF THE EYE\\nrule, above reported, and myopic astigmatism against the rule,\\nto be reported, in regard to the vertical meridian.\\nMrs. N. E. R., aged thirty-nine, consulted me March 2,\\n1897. She had worn glasses for a year, but her eyes continued\\nto pain her when she did any near work. Frontal headaches,\\ndizziness, and a drawing sensation in the eyes are the symptoms\\nmost complained of.\\nOphthalmometer. Astigmatism against the rule, .50 D.,\\naxis 15\u00c2\u00b0 -h or 105\u00c2\u00b0 right eye .25 D., axis 165\u00c2\u00b0 or 75\u00c2\u00b0 left\\neye.\\nR. E.\\nL. E,\\nFig. 39.\\nThe primary position in the right eye was found at 15\u00c2\u00b0,\\nthe images of the mires approximated and the long indicator\\nturned to 105\u00c2\u00b0 when the images separated the images were\\nagain approximated and the long indicator turned back to 15\u00c2\u00b0,\\nthe primary position, when an overlapping of one-half a step\\ntook place. In astigmatism against the rule it is after this\\nsecond turning that the axes and the amount of astigmatism\\nare read off, the long indicator always showing where the\\nplus glass will be worn if hypermetropia is present and the", "height": "4262", "width": "2698", "jp2-path": "refractionofeye00davi_0092.jp2"}, "93": {"fulltext": "ILLUSTRATIVE CASES 75\\nshort indicators where the minus glass will be worn if myopia\\nis present.\\nIn the left eye the primary position was found at 165\u00c2\u00b0, the\\nsecondary at 75\u00c2\u00b0 where the images separated. The images\\nwere again approximated and turned back to the primary\\nposition, when an overlapping of a quarter of a step took place,\\nreading, therefore, astigmatism against the rule, .25 D., axis\\n165\u00c2\u00b0 4- or 75\u00c2\u00b0-.\\nTest cards and trial lenses.\\nK. V. 1^ f W. 1 D. cyl., 15\u00c2\u00b0.\\nL. V. 12- W. .50 D. cyl., 165\u00c2\u00b0.\\nReads Jaeger No. 1 at 8 inches.\\nOphthalmo scope, Simple hypermetropic astigmatism against\\nthe rule each eye. Ordered\\n1 D. cyl., 15\u00c2\u00b0 right eye\\n.50 D. cyl., 165\u00c2\u00b0 left eye.\\nCase XXVI. Astigmatism with axes at 45\u00c2\u00b0 and 135\u00c2\u00b0.\\nAnnie D., aged 14, was examined by me at the clinic July 10,\\n1894. She was in good health, but suffered constantly from\\nher eyes, more when she used them for close work. In fact, it\\nwas a typical case of asthenopia.\\nOphthalmometer. Astigmatism with the rule, 2 D., axis 45\u00c2\u00b0\\nor 135\u00c2\u00b0 right eye astigmatism against the rule, 2D.,\\naxis 135\u00c2\u00b0 or 45\u00c2\u00b0 left eye.\\nPerhaps it is well here again to refer to the fact that Avhen\\nthe two chief meridians of curvature fall exactly at 45\u00c2\u00b0 and 135\u00c2\u00b0,\\njust halfway between the vertical and horizontal meridians,\\nthat, strictly speaking, we do not have astigmatism with or\\nagainst the rule. But for the sake of uniformity of reading of", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0093.jp2"}, "94": {"fulltext": "76\\nTHE REFRACTION OF THE EYE\\nthe instrument we speak of these cases as being with and\\nagainst the rule, just as in other cases.\\nFurthermore, to make the reading of the instrument uniform,\\nwe have assumed one or the other of the meridians, either 45\u00c2\u00b0\\nor 135\u00c2\u00b0, always as the primary position or starting point. For\\nmyself I always take 135\u00c2\u00b0 as the primary position in such cases.\\nStarting with 135\u00c2\u00b0 as the primary position and turning the\\nlong indicator to 45\u00c2\u00b0, that is at right angles, if the mires over-\\nR. E.\\nL. E.\\nFig. 40.\\nlap we call the astigmatism with the rule, just as at other times\\nwhen the mires overlap and if the mires separate when we\\nreach 45\u00c2\u00b0 we call it astigmatism against the rule, approximate\\nthe mires a second time, and turn back to the primary -position\\nat 135\u00c2\u00b0 to get the amount of overlapping.\\nIt must be remembered, too, in these cases with the axes at\\n45\u00c2\u00b0 and 135\u00c2\u00b0, that the subtraction of .50 D. from the reading\\nof the instrument when the astigmatism is with the rule and\\nthe addition of .50 D. to the reading when it is against the\\nrule does not always hold.", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0094.jp2"}, "95": {"fulltext": "ILLUSTKATIVE CASES\\n7T\\nIn the present case in the right eye the lines dividing the\\nmires became straight with each other at 135\u00c2\u00b0 (primary position)\\nthe images of the mires were then approximated and turned to\\n45\u00c2\u00b0 (secondary position), when two steps of overlapping took\\nplace astigmatism with the rule, 2 D., axis 45\u00c2\u00b0 or 135\u00c2\u00b0\\nIn the left eye the primary position was also found at 135\u00c2\u00b0, the\\nimages of the mires approximated, and the long indicator turned\\nto 45\u00c2\u00b0 (second position), when the images of the mires separated.\\nThe images were again approximated, and the long indicator\\nturned back to the primary position at 135\u00c2\u00b0, when they over-\\nlapped two steps; astigmatism against the rule, 2 D., axis\\n135\u00c2\u00b0 or 45\u00c2\u00b0\\nTest cards and trial lewises.\\n50\\n2_0 W I 2\\n3\\n=M-I^W. 1.50D. cyl., 45\u00c2\u00b0.\\nD. cyl.,135\u00c2\u00b0.\\nReads Jaeger No. 1 at 5 inches.\\nOphthalmoscope. Simple hypermetropic astigmatism.\\nJuly 8, second test was given and the patient accepted the\\nsame glass. Ordered\\n1.50 D. cyl., 45\u00c2\u00b0 right eye\\n2 D. cyl., 135\u00c2\u00b0 left eye.\\nThe lines on Green s clock-dial from I to YII and from II to\\nVIII were seen plainest with the right eye and the lines from\\nX to IV and from XI to V in the left eye.\\nThe reason that the patient saw two sets of lines plainly in\\neach eye is that there are no lines on Green s dial corresponding\\nexactly to 45\u00c2\u00b0 and 135\u00c2\u00b0. The lines on the clock-dial correspond\\nto 0\u00c2\u00b0 or 180\u00c2\u00b0, 30\u00c2\u00b0, 60\u00c2\u00b0, 90\u00c2\u00b0, 120\u00c2\u00b0, and 150\u00c2\u00b0. As a consequence\\nthere are two sets of lines equidistant on either side of 45\u00c2\u00b0, and\\ntwo sets equidistant on either side of 135\u00c2\u00b0, seen equally plainly\\nwhen the axes happen to be exactly at 45\u00c2\u00b0 and 135\u00c2\u00b0. A glance\\nat the clock-dial will quickly show how this is. Perhaps a better", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0095.jp2"}, "96": {"fulltext": "78\\nTHE REFRACTION OF THE EYE\\nset of lines are those of Snellen, fan-shaped, which are much\\ncloser together than those on Green s clock-dial, corresponding-\\nat least to every fifteen degrees.\\nI may say here by way of explanation of the principle of\\nGreen s clock-dial arrangement of lines, that when the horizon-\\ntal lines are seen plainest, assuming no spasm of accommoda-\\ntion to be present, the presence of one of six conditions of\\nerror of refraction is indicated (1) a simple hypermetropic\\nastigmatism, (2) a compound hypermetropic astigmatism, (3) a\\nmixed astigmatism with the hypermetropic portion greater than\\nthe myopic portion, all with the rule or (4) a simple myopic\\nastigmatism, (5) a compound myopic astigmatism, (6) a mixed\\nastigmatism with the myopic portion greater than the hyper-\\nmetropic portion, all against the rule. A glance at Figs. 9,\\n10, 13, 16, 17, 18, in Chapter II, will show this, the lines that\\nare seen plainest always corresponding with the meridian of\\ngreatest error of refraction.\\nThe horizontal meridian in all of the above cases is the one\\nmost at error, while the vertical is emmetropic or more nearly\\nso than the horizontal in all of them. As the horizontal lines\\non the clock-dial are seen by means of the rays of light that\\npass through the vertical\\nmeridian of the cornea, it\\nfollows as a consequence\\nthat the horizontal lines\\non the dial will be seen\\nplainest in the above cases.\\nThis is based on a simple\\nprinciple of optics. We\\nsee lines by means of rays\\nof light that light them\\nup from side to side (a, a\\\\ Fig. 41), and not by the rays of\\nlight that strike them in their horizontal or longitudinal direc-\\ntion (b, b Fig. 41).\\nCb a OL a\\nFig. 41. Showing how lines are seen by rays\\nof light that strike them from side to side,\\na, a and not by rays that strike them at\\ntheir ends, 6, b", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0096.jp2"}, "97": {"fulltext": "GREEN S CLOCK-DIAL\\n79\\nOn the other hand, had the vertical lines been seen plainest,\\nthis would have indicated one of six other conditions, to wit\\n(1) Simple myopic astigmatism, (2) com-\\npound myopic astigmatism, (3) mixed\\nastigmatism with the myopic portion\\ngreater than the hypermetropic, all with\\nthe rule or (4) simple hypermetropic\\nastigmatism, (5) compound hyperme-\\ntropic astigmatism, (6) mixed astigmatism\\nwith the hypermetropic portion greater\\nthan the myopic portion, all against the\\nrule.\\nThe horizontal meridian is emmetropic\\nor more nearly so than the vertical in all\\nT rm p 1 -1 Showing how\\nsix conditions. Therefore the vertical vertical lines are seen\\nlines on the clock-dial will be seen plain- ^y ^^y^ ^^s^^\\n^T^- Act\\\\ Strike them\\nest (J^lg. 42). from side to Side.\\nT)\\nUj\\na.\\na\\nb", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0097.jp2"}, "98": {"fulltext": "CHAPTER lY\\nCOMPOUND HYPERMETROPIC ASTIGMATISM ILLUSTRATIVE\\nCASES SPASM OF ACCOMMODATION\\nIn compound hypermetropic astigmatism the ophthalmom-\\neter is used in exactly the same way as in simple hypermetropic\\nastigmatism or, for that matter, as in every form of astigma-\\ntism, that is, to find the position of the two principal meridians\\nof curvature of the cornea and the amount of the astigmatism.\\nThese points once obtained, the character of the error of refrac-\\ntion, if hypermetropic or myopic, is, in the great majority of\\ncases, easily found out with the aid of the trial case, aided by\\nthe ophthalmoscope and other objective tests. In exceptional\\ncases a mydriatic has to be called into requisition before a\\nsatisfactory glass can be prescribed, but such cases are very\\nrare, as shown in the preceding chapter.\\nHere again I wish to emphasize the importance of correcting\\nthe astigmatism first for if there happens to be only a simple\\nastigmatism present, we have gone to the root of the trouble at\\nonce and if a spherical error is present in addition to the\\nastigmatism, we have disposed of the astigmatism and have\\nonly the spherical error left to deal with, as in simple hyper-\\nmetropia and myopia. This method of procedure is of great\\nadvantage when there is a tendency to spasm of accommodation\\nfor, after the astigmatism has been corrected in each eye\\nseparately, we can then put spherical glasses before both eyes\\nat once. In this way, as is well known, the tendency to spasm\\nof accommodation is overcome, and the patient many times\\naccepts stronger plus, or weaker minus, glasses than when one\\n80", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0098.jp2"}, "99": {"fulltext": "COMPOUND HYPERMETROPIC ASTIGMATISM 81\\neye is tested at a time. However, it should not be forgotten\\nthat spherical glasses should be tried in addition to the cylindri-\\ncal glasses on each eye separately, before both eyes are tried\\ntogether, for there may be more spherical error in one eye than\\nthe other. For example, say the patient accepts in the right\\neye 1 D. -j- 2 D. cyl., 90\u00c2\u00b0, and in the left eye .50 D.\\n2 D. cyl., 90\u00c2\u00b0, when each eye is tested separately. If we\\nsuspect spasm of accommodation, we should leave the cylin-\\ndrical glasses as they are and place in front of them at the\\nsame time a .25 D. stronger spherical glass than they accepted\\nsingly. In this instance, in front of the right eye 1.25 D.\\nand in front of the left .75 D. If these are accepted, add\\n.25 D, stronger sphere yet, and continue till the vision begins to\\nbe made worse. Where the patient does not accept as strong\\na cylindrical glass as indicated by the ophthalmometer, I often\\ntry both eyes at the same time with cylindrical glasses. Of\\ncourse, this is after the eyes have been tried separately, when\\nboth cylindrical glasses can be increased proportionately in\\nstrength, just as in the case of spherical glasses.\\nIn compound hypermetropic astigmatism, spasm of accom-\\nmodation is more often present perhaps than in any other form\\nof error of refraction. I have already shown in Chapter III,\\npage 42 et sequiter, how it may be avoided if the test is begun\\nand conducted properly. In the latter part of this chapter I\\ntreat of it in detail, its causes, signs of its presence, and how\\nto overcome it in most cases without the unnecessary use of\\nmydriatics, together with illustrative cases. In this way I\\nhope to show that this bugbear of refraction is not so much to\\nbe dreaded after all, and that a mydriatic is not the only Aveapon\\nit can be fought with, though occasionally it has to be called\\ninto requisition as a last resort.\\nI am not among those who believe in the use of the milder\\nmydriatics, such as homatropine, because I believe when a\\nmydriatic is needed, it is needed, and I use an efficient one", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0099.jp2"}, "100": {"fulltext": "82 THE REFRACTION OF THE EYE\\nwhen I do use one, which is seldom. The two that I rely upon\\nare atropine and scopolamine. The atropine is used in 4 grains\\nto 5 1 solution for adults and half that strength for children,\\none drop being instilled into each eye three times a day for\\nthree days, after which the test is made. Then a week is\\nallowed to elapse for the effects to wear off, Avhen another test\\nis made, and usually the glass that the patient accepts on this\\nlast test is given. For, while it will not be so strong a glass as\\nthe patient accepted under the atropine, yet it will be stronger\\nthan the glass that was accepted before the mydriatic was\\ninstilled, because the week s enforced rest under the mydriatic\\nhas left the eye quiet and relieved the spasm of accommodation.\\nHowever, should the glasses accepted on this last test not be\\nstrong enough, as compared by the glasses accepted while under\\nthe influence of the mydriatic, a large amount of latent hyper-\\nmetropia being present, I correct part of this latent hyperme-\\ntropia (one-half to two-thirds of it) in addition to the manifest\\nhypermetropia.\\nPatients when given atropine to take home with them to be\\ninstilled into the eyes should be cautioned as to its poisonous\\neffects at times, especially in children. Any flushing of the\\nface or dryness of the throat should be the sign to stop its use.\\nScopolamine hydrobromid, 1 gr. to \u00c2\u00a7i solution for adults\\nand half that strength for children, is a very efficient and quick\\nmydriatic. It is to be instilled into the eye of the patient by\\nthe doctor in the office, one drop in each eye every five minutes\\nfor thirty minutes, having the patient press his fingers over the\\ntear-sac at the inner canthus of each eye all the while, so that\\nnone of the solution goes into the nose. Then have the patient\\nwait for thirty minutes (one hour in all) before the test is\\nbegun.\\nThe advantages of scopolamine over atropine are (1) that\\nit is more powerful (2) it acts quicker, getting the patient\\nready for testing in one hour s time (3) its effects disappear", "height": "4257", "width": "2698", "jp2-path": "refractionofeye00davi_0100.jp2"}, "101": {"fulltext": "MYDRIATICS 83\\nmore rapidly, lasting only from two to five days, while the\\neffects of atropine last a week to ten days. Some few cases of\\npoisoning have been reported from its use in the eyes,^ the\\ntoxic symptoms rapidity of the pulse, flushing of the face,\\ndryness of the throat, dizziness, at times nausea, and, in extreme\\ncases, delirium being alarming in some cases. In most of the\\ncases of poisoning reported, either the precaution of pressing\\non the tear-sac was not observed or the drug was used too\\nfreely. Just as with atropine, some cases are much more\\nsusceptible to it than others, hence it should be used with\\ncaution. However, with proper precaution it can be used with\\nsafety.\\nAmblyopia, which is often present in high degrees of com-\\npound hypermetropic astigmatism, is often a stumbling-block\\nfor beginners, on account of which they often use a mydriatic\\nwhen none is called for. In such cases, not being able to\\nimprove the vision much with any glass, they think perhaps it\\nis their own fault in not fitting the glasses correctly that the\\npatient does not obtain better vision, not stopping to consider\\nthat amblyopia may be present, and that no glass whatever will\\ngive better vision. They accordingly use a mydriatic, but find\\nafter all that the patient cannot be made to see any better\\nivith the glasses accepted under the use of a mydriatic than with\\nthose accepted at first. They have simply had their trouble\\nlor nothing besides giving the patient great inconvenience.\\nMy own practice in such cases is to give two tests on\\ndifferent days. If the second test corresponds with the first, I\\norder the glasses that are accepted though they do not improve\\nthe vision much. By the use of the ophthalmometer we know\\nif any corneal astigmatism is present or not, and, if present, its\\naxis and amount. With this important point ascertained we\\nknow approximately beforehand what cylindrical glass the\\n1 Pooley, Foster, and Smith, among others, in this country, while several\\n\u00e2\u0080\u00a2cases have been reported abroad.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0101.jp2"}, "102": {"fulltext": "84 THE REFRACTION OF THE EYE\\npatient should accept and do not have to depend so much on\\nhis answers. After the astigmatism is once corrected, the\\nspherical part of the error is corrected with comparative ease.\\nOf course, if the two tests do not agree, and if there is a ques-\\ntion of spasm of accommodation, I do not hesitate to use a\\nmydriatic, and a strong one. After a mydriatic has been em-\\nployed, retinoscopy may be brought to the aid of the other tests.\\nBut without the use of a mydriatic I have not found retinoscopy\\nsatisfactory for that reason I rarely employ retinoscopy in my\\npractice, since I use mydriatics so seldom.\\nSome illustrative cases will serve to bring out the points I\\nhave mentioned above.\\nCase XXVII. Ophthalmometer shotvs astigmatism tvith the\\nrule, 1 D. Patient accepts compound plus glasses with relief of\\nasthenopia and conjunctivitis. Sophia F., aged twenty-four,\\nin good health, complains that she has frequent headaches,\\nand that her eyes ache after using them, also that the ej^elids\\nitch and burn at times.\\nOphthalmometer. Astigmatism with the rule, 1 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 in each e^^e.\\nTest cards and trial\\nR. V. 1^ 1^ W. .50 D. .50 D. cyl., 90\u00c2\u00b0.\\nL. V. =1^- :f^ W. -f-.50D. +.50 D. cyl., 90\u00c2\u00b0.\\nReads Jaeger No. 1 at 6 inches.\\nOphthalmoscope. Hypermetropia in the vertical meridian\\n1.50 D., and in the horizonal meridian 2 D., in each eye respec-\\ntively.\\nOn account of a mild conjunctivitis, an astringent wash was\\nordered for the lids and the patient directed to return in two\\nweeks.\\nSecond test the ophthalmometer reads the same as at the\\nfirst test.", "height": "4262", "width": "2698", "jp2-path": "refractionofeye00davi_0102.jp2"}, "103": {"fulltext": "ILLUSTRATIVE CASES 85\\nTest cards and trial lenses.\\n=i^ U W. 1 D. .50 D. cyl., 90\u00c2\u00b0.\\nL. V. f^ 1^ W. 1 D. .50 D. cyL, 90\u00c2\u00b0.\\nThe ophthalmoscope showed about the same condition as on\\nthe first test. Tlie conjunctivitis is much improved. Ordered\\n1D. +.50 D. cyl., 90\u00c2\u00b0 each eye. These glasses have been\\nworn for more than four years with relief from her asthenopic\\nsymptoms.\\nCase XXVIII. Large amount of astigmatism with the axis\\nslanting relatively the same number of degrees from the vertical\\nmeridian., 15\u00c2\u00b0 to the nasal side^ in each eye Patient accepts a\\ncompound plus glass with relief of asthenopic symptoms. March\\n14, 1893, Mary D., aged twenty-four, in good health, but her\\neyes ache after she uses them for a short time for close work,\\nespecially in the evening.\\nOphthalmometer. Astigmatism with the rule, 3 D., axis\\n75\u00c2\u00b0 or 165\u00c2\u00b0 right eye 3 D., axis 105\u00c2\u00b0 or 15\u00c2\u00b0 left eye.\\nR.E. L.E.\\nFig. 43.\\nTest cards and trial lenses.\\nR. V. f-J 2^ W. 3 D. 4- 2.50 D. cyl., 75\u00c2\u00b0.\\nL. y. II 1^ W. 3 D. 2.50 D. cyl., 105\u00c2\u00b0.\\nReads Jaeger No. 1 at 6 inches.\\nOphthalmoscope. Hypermetropia 3.50 D. at 75\u00c2\u00b0 and 6.50\\nD. at 165\u00c2\u00b0 right eye; and 3.50 D. at 105\u00c2\u00b0 and 6.50 D. at 15\u00c2\u00b0\\nleft eye.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0103.jp2"}, "104": {"fulltext": "86\\nTHE REFRACTION OF THE EYE\\nThe lines on the clock-dial from II to VIII were seen best\\nwith the right eye, and from X to IV in the left eye. The\\nsimple cylindrical glass before each eye served to bring out all\\nthe lines on the clock-dial equally clear, indicating that the\\nastigmatism had been corrected. On a second test the patient\\naccepted exactly the same glass as on the first test, and it was\\nordered, and has been worn with comfort ever since.\\nCase XXIX. Astigmatism against the rule, 1 D., with the\\naxis 15\u00c2\u00b0 from the horizontal meridian in each eye; Patient accents\\ncompound plus glasses and gets relief from asthenopia. May 11,\\n1892, Mrs. C. W. T., aged thirty-nine, in good general health,\\nB. E,\\nL.E.\\nFig. 44.\\ncame for glasses on account of painful vision and headaches.\\nThe pupil in the left eye was dilated for some weeks when she\\nwas a child, from some unknown cause. She never had scarlet\\nfever or diphtheria, or any serious illness.\\nOphthalmometer. Astigmatism against the rule, ID., axis\\n15\u00c2\u00b0 4- or 105\u00c2\u00b0- right eye; 1 D., axis 165\u00c2\u00b0 or 75\u00c2\u00b0- left\\neye.", "height": "4249", "width": "2698", "jp2-path": "refractionofeye00davi_0104.jp2"}, "105": {"fulltext": "ILLUSTRATIVE CASES 87\\nTest cards and trial lenses.\\nR. V. If ff W. 1 D. 1 D. cyl., 15^\\nL. V. f^ ff W. .75 D. 1 D. cyl., 165\u00c2\u00b0.\\nReads Jaeger No. 1 at 8 inches.\\nOphthalmoscope. R. 2.50 D. at 105\u00c2\u00b0 and 1.50 D. at 15\u00c2\u00b0,\\nright eye H. 2.50 D. at 75\u00c2\u00b0 and 1.50 D. at 165\u00c2\u00b0, left eye.\\nOn a second test, three days later, the patient accepted\\nexactly the same glass in the left eye and a quarter diopter\\nweaker spherical glass in the right. Ordered\\n.75 D. 1 D. cyl., 15\u00c2\u00b0 right;\\n.75 D. 1 D. cyl., 165\u00c2\u00b0 left.\\nThese glasses have been worn for five years with comfort.\\nHowever, as she is becoming presbyopic, she will soon have\\nto wear stronger glasses for reading and close work.\\nCase XXX. Small amount of astigmatism associated ivith\\na large amount of hyper metropia Marked asthenopia; Relief with\\nglasses. November 27, 1893, Miss M. H., aged thirty-five, in\\ngood health, came for glasses because her old glasses did not\\nsuit her. She has worn glasses for the last six years. The\\nvision blurs after reading for a few moments, and she has to\\nstop and rub the eyes before she can continue.\\nOphthalmometer. Astigmatism with the rule, 1.25 D.,\\naxis 90\u00c2\u00b0 or 180\u00c2\u00b0 right eye 1.25 D., axis 105\u00c2\u00b0 or 15\u00c2\u00b0\\nleft eye.\\nTest cards and trial lenses.\\n2% I* W. 4 D. .75 D. cyl., 90\u00c2\u00b0.\\nR. L. 2V0 -I* W. 4 D. .75 D. cyl., 105\u00c2\u00b0.\\nReads Jaeger No. 1 at 7|- inches.\\nOphthalmoscope. H. 4 D. at 90\u00c2\u00b0 and 5 D. at 180\u00c2\u00b0 right\\neye H. 4 D. at 105\u00c2\u00b0 and 5 D. at 15\u00c2\u00b0 left eye.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0105.jp2"}, "106": {"fulltext": "88\\nTHE REFRACTION OF THE EYE\\nA second test resulted in the patient accepting exactly\\nthe same glass as at the first test, and it was ordered. They\\nhave been worn four years, with entire relief of asthenopia\\nsymptoms.\\nThe point of interest in this case, as far as fitting the\\nglasses is concerned, is the order of sequence in which the\\nglasses should be placed in the trial frames during the test.\\nThat is, if cylindrical glasses should be tried first, or spherical\\nB. E.\\nL. E,\\nFig. 45.\\nglasses. In an article on the Technics of the Trial Case,^ I have\\nstated it as a rule to be generally followed, that in cases of\\ncompound astigmatism it is always best to correct the astig-\\nmatism first, unless there is a large amount of spherical error\\npresent, a hypermetropia of 6 D. or more, a myopia of\\n8 D. or more, with only a small amount of astigmatism\\npresent. Perhaps in that statement I gave the amount of\\nthe spherical error too large in cases where it is necessary\\nfirst to correct part of the spherical error before correcting\\n1 iVeic York Med. Jour., June 20, 1896.", "height": "4254", "width": "2698", "jp2-path": "refractionofeye00davi_0106.jp2"}, "107": {"fulltext": "ILLUSTRATIVE CASES 89\\nthe astigmatism for I have sometimes found it necessary in\\ncases of hypermetropia of only 4 D., and in myopia of only\\n6 D., with a small amount of astigmatism present, to correct\\npart of the spherical error before the patient could appreciate\\nthe effect of a weak cylindrical glass when placed in front of\\nthe eye. In fact, in the present case, with 4 D. of hypermetro-\\npia and 1.25 D. of corneal astigmatism, part of the spherical\\nerror had to be corrected first before the cylindrical glasses\\ncould be appreciated. Usually, however, in cases of hyperme-\\ntropia of 4 D. and less and myopia of 6 D. and less, compli-\\ncated with an astigmatism of as much as 1 D., the cylindrical\\nglass will be appreciated and vision improved to a slight\\nextent with it alone, and before the spherical glass is added.\\nThe tendency in such cases, large amount of spherical error\\nassociated with small amount of astigmatism, where the\\ncylindrical glasses are tried first, is for the patient to accept\\ntoo strong cylindrical glasses. I am careful in such cases, at\\nthe close of the test, to weaken the cylindrical glasses slightly\\nand at the same time to i\u00c2\u00abncrease the strength of the spherical\\nglasses a little, to see if the vision is improved by the change.\\nIf it is, I make the change if not, I give the original glass\\nas first accepted. I mention this fact here for the benefit of\\nbeginners and because it is a point of practical importance.\\nI may say, on the other hand, for those who make it a habit\\nto correct the spherical error first, that the reverse condition\\nholds that is, the patient is liable to accept too strong a spheri-\\ncal glass relative to the cylindrical glass. In such case it is\\nwell to weaken the spherical glass at the close of the test and\\nat the same time increase the strength of the cylindrical glass\\nto find if vision can be improved.\\nAgain, in such cases as the one reported, the patient may\\naccept the cylindrical glass as indicated by the ophthalmometer\\nwithout either improving or making the vision worse. In\\nsuch a case, leave the cylindrical glass on and proceed to cor-", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0107.jp2"}, "108": {"fulltext": "90 THE REFRACTION OF THE EYE\\nrect the spherical error. When this is corrected, you will\\nfind that the vision is made worse if the cylindrical glass is\\nremoved, though while the cylindrical glass was on alone it\\nseemed not to affect the vision one way or the other. This is\\neasily accounted for. The spherical error being large, and the\\nastigmatism being small, the cylindrical glass while on by\\nitself has but little appreciable effect, but w^hen the spherical\\nerror is corrected (if there is not a marked amblyopia present),\\nthe vision is brought up to something like the normal, and the\\neye can then appreciate the presence or absence even of a weak\\ncylindrical glass, which it could not do at first.\\nCase XXXI. Hypermetropic astigynatism in each eye of\\nequal amount^ 2 D. Patient accepts a simple plus cylindrical glass\\nin 07ie eye, and a compound plus glass in the other; Relief from\\nasthenopia. May 9, 1893, Hannah D., aged twenty-five, has\\ngood general health, but has had weak eyes since a child. After\\nany close work she has headaches and pains in the eyes, espe-\\ncially the left eye.\\nOphthalmometer. Astigmatism with the rule, 2 D,, axis\\n75\u00c2\u00b0 or 165\u00c2\u00b0 right eye 2 D., axis 120\u00c2\u00b0 or 30\u00c2\u00b0 left eye.\\nTest cards aiid trial lenses.\\nR. V. =f^- :f\u00c2\u00a7W. -I-1.75D. cyl., 75\u00c2\u00b0.\\nL. V. f II W. 1.50 D. cyl., 120\u00c2\u00b0.\\nReads Jaeger No. 1 at 5J inches.\\nOphthalmoscope. H. 2 D. at 165\u00c2\u00b0 and emmetropia at\\n75\u00c2\u00b0 right eye; H. .50 D. at 120\u00c2\u00b0 and H. 2 D. at 30\u00c2\u00b0 left\\neye.\\nTwo days later a second test was made. The ophthalmom-\\neter read exactly the same, both as to the axis and amount\\nof the astigmatism in the left eye as at the first test and\\nthe same axis, but .50 D. more in amount for the right\\neye.", "height": "4241", "width": "2698", "jp2-path": "refractionofeye00davi_0108.jp2"}, "109": {"fulltext": "ILLUSTRATIVE CASES\\nTest cards and trial lenses.\\nR. V. li 1^- W. 2 D. cyl., 75\u00c2\u00b0.\\nL. V. f 1^ W. .50 D. 1.50 D. cyL, 120\\nReads Jaeger No. 1 at 51 inches.\\n91\\nR. E,\\nL. E.\\nFig. 46.\\nThis last glass was ordered and has been worn constantly\\nsince, with relief from asthenopic symptoms.\\nCase XXXII. Compound hypermetropic astigmatism agairist\\nthe rule iii one eye; Large amount of hypermetropia in the other\\neye Marked asthenopia Relief with the use of glasses.\\nDecember 17, 1895, Frances D. M., aged twenty-one, in poor\\ngeneral health, and is very nervous and easily excited or de-\\npressed. Her mother was a very nervous woman also. The\\npatient suffers much from fatigue and often has headaches,\\nand her eyes pain after any close work or reading. There is\\na mild conjunctivitis present.\\nOphthalmometer. Astigmatism against the rule, .25 D.,\\naxis 30\u00c2\u00b0 or 120\u00c2\u00b0 right eye astigmatism with the rule,\\n.50 D., axis 90\u00c2\u00b0 -f- or 180\u00c2\u00b0 left eye.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0109.jp2"}, "110": {"fulltext": "92\\nTHE REFRACTIOX OF THE EYE\\nTest cards and trial lenses.\\nI^- t\u00c2\u00a5 It W. 3 D. .75 D. cyL, 30\u00c2\u00b0.\\nReads Jaeger No. 1 at 6 inches with the right eye, Jaeger\\nNo. 4 at the same distance with the left.\\nOphthalmoscope. \u00e2\u0080\u0094R, 4 D. at 120\u00c2\u00b0 and 3 D. at 30\u00c2\u00b0 right\\neye H. 7 D., left eye.\\nR. E.\\nL. E.\\nFig. 47.\\nThe second test resulted in the patient accepting the same\\nglass as at the first test, and they were accordingly ordered.\\nShe has worn these glasses for eighteen months with great\\ncomfort, though at times she suffers from headaches when\\ngreatly exhausted. Her general health has improved con-\\nsiderably, but she is still easily excited.\\nThe ophthalmometer in this case was of great service in\\npointing out the small amount of astigmatism against the rule,\\nin the right eye, and also the small amount of astigmatism\\n1 A note from the patient (June, 1898) informs me that she is still wearing\\nthe glasses with comfort, and that her health remains fairly good.", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0110.jp2"}, "111": {"fulltext": "ILLUSTRATIVE CASES 93\\nwith the rule, in the amblyopic left eye, which was neutralized\\nby the lenticular astigmatism. In fact, had not the ophthal-\\nmometer been used in the case, it would have been necessary\\nto have used a mydriatic in order to fit the correct glasses.\\nThis would have meant a week or ten days of widely dilated\\npupils, with much disturbance of vision, to an already excita-\\nble and nervous patient, and with no better nor even with as\\ngood result, as she had been fitted the year previously under a\\nmydriatic with glasses that were not at all satisfactory.\\nCase XXXIII. Compound hypermetropic astigmatism with the\\nchief meridians of curvature at 45\u00c2\u00b0 and 135\u00c2\u00b0; Marked asthenopia\\nRelief with glasses. February 25, 1894, Bertha F., aged thirty-\\nnine, in good general health, has had weak eyes since a\\nchild. When thirteen years old she had drops, salve, and\\nglasses prescribed. She had but little trouble after that until\\neight years ago, when the eyes became painful, the eyelids red,\\nand troublesome headaches followed, after using the eyes for\\nclose work. She again had salve, drops, and glasses pre-\\nscribed, but her eyes have continued painful and the lids red.\\nShe now has a well-marked blepharitis marginalis, and is fre-\\nquently troubled with headaches. I ordered a mild astringent\\nwash and yellow oxide of mercury ointment (2 grains to 3ii),\\nand after two weeks made the first test for glasses.\\nOphthalmometer. Astigmatism against the rule, 75 D.,\\naxis 135\u00c2\u00b0 or 45\u00c2\u00b0 right eye astigmatism with the rule,\\n75 D., axis 45\u00c2\u00b0+ or 135\u00c2\u00b0- left eye.\\nTest cards and trial lenses.\\nR. V. ff ff W. .75 D. .25 D. cyl., 135\u00c2\u00b0.\\nL. V. ff-: fl W. 1 D. +.25D. cyl., 45\u00c2\u00b0.\\nReads Jaeger No. 1 at 1^ inches.\\nOphthalmoscope. Hypermetropia of 1.50 D. in each eye.\\nIt was impossible to estimate the small amount of astigmatism.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0111.jp2"}, "112": {"fulltext": "94\\nTHE REFRACTION OF THE EYE\\nSecond test, three days later, resulted as follows Oph-\\nthalmometer gave the same reading as on the previous exami-\\nnation.\\nTest cards and trial lenses.\\nR. V. fl ff W. 1.25 D. .25 D. cyl., 135\u00c2\u00b0.\\nL. V. fl ff W. 1.25 D. .25 D. cyl., 45\u00c2\u00b0.\\nR. E.\\nL. E.\\nFig. 48.\\nThe ophthalmoscope showed the same amount of H. as at\\nthe first examination. Ordered\\n1.25D. +.25D. cyl., 135\u00c2\u00b0;\\n1.25D. .25D. cyl., 45\u00c2\u00b0.\\nThese glasses have been worn constantly for three and one-\\nhalf years, and with entire relief of her blepharitis margin alis\\nand freedom from asthenopia. Within a month a-|-.50D.s\\nhas been added to the distance glasses for reading purposes,\\non account of presbyopia, she being now 42^ years of age.", "height": "4249", "width": "2698", "jp2-path": "refractionofeye00davi_0112.jp2"}, "113": {"fulltext": "ILLUSTEATIVE CASES 95\\nHere again the ophthalmometer was of great assistance,\\nfor it pointed out the small amount of astigmatism that was\\npresent and at the unusual axes of 45\u00c2\u00b0 and 135\u00c2\u00b0, which\\nastigmatism, by the way, had been overlooked at her previous\\ntests under a mydriatic. The instrument read astigmatism\\nagainst the rule in the right eye and with the rule in the left\\neye, and an equal amount in each, .75 D. In the right eye,\\ninstead of adding .50 D. to the reading of the instrument, as\\nis usual in cases of astigmatism against the rule, .50 D. had\\nto be deducted, just as in the left eye, where the astigmatism\\nwas with the rule. It must be remembered here, as I have\\nalready pointed out in Chapter II, that, when the chief merid-\\nians of curvature are at 45\u00c2\u00b0 and 135\u00c2\u00b0, the exact halfway points\\nbetween 0\u00c2\u00b0 and 90\u00c2\u00b0 on one side, and 90\u00c2\u00b0 and 180\u00c2\u00b0 on the other\\nside of the 90\u00c2\u00b0, the terms with the rule and against the\\nrule do not strictly hold, for the meridians at these points\\nare just as near to 90\u00c2\u00b0 as they are to 180\u00c2\u00b0. In other words,\\nthey are on the dividing lines between astigmatism with the\\nrule and astigmatism against the rule. Consequently the\\nusual addition of .50 D. to the reading of the instrument, as\\nin astigmatism against the rule, and the subtraction of .50 D.\\nfrom it, as in astigmatism with the rule, does not hold very\\nstrictly in these cases. Knowing the axis of the astigmatism,\\nhowever, the amount of it, even were it not indicated by the\\ninstrument, is usually easily obtained by the subjective test\\nwith the trial glasses, especially if the method of beginning\\nthe test with the weakest plus glass and gradually increasing\\nit in strength is followed. For instance, in this case I began\\nthe subjective test, right eye, with+.25D. cylindrical glass,\\naxis 135\u00c2\u00b0, which was accepted with improvement in vision.\\nThen +.50 D. cyl., same axis, was tried, but not accepted.\\nThen +.25 D. sphere was added to the +.25 D. cyl., which\\nimproved vision. The spherical glass was increased in\\nstrength +.25 D. at a time, till the patient accepted +1.25 D.s", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0113.jp2"}, "114": {"fulltext": "96 THE REFRACTIO:^ OF THE EYE\\nin addition to the +.25 D. cyl., axis 135\u00c2\u00b0, which gave him the\\nbest vision. Exactly the same course was pursued with the\\nleft eye.\\nI give a second case with axes like the above, but where\\nboth the astigmatism and spherical error are much greater\\nin amount and associated with amblyopia.\\nCase XXXIV. Large amount of compound hypermetro pic\\nastigmatisyn with the main meridians at 45\u00c2\u00b0 and 135\u00c2\u00b0; Severe\\nasthenopia-, Amblyopia; Relief with glasses. July 15, 1898,\\nM. B., aged thirty, in good general health, consulted me about\\nher eyes because of great pain in them, and on account of\\nvision blurring when she tried to do any close work. She\\nhas always had weak eyes, and has suffered greatly with\\nthem, but says she has been afraid to consult an oculist for\\nfear that her sight would be made worse.\\nR. E,\\nL. E.\\nFig. 49.\\nOphthalmometer. Astigmatism with the rule, 3D., axis\\n45\u00c2\u00ae -h or 135\u00c2\u00b0 right eye astigmatism against the rule, 3D.,\\naxis 135* or 45\u00c2\u00b0 left eye.", "height": "4257", "width": "2786", "jp2-path": "refractionofeye00davi_0114.jp2"}, "115": {"fulltext": "ILLUSTRATIVE CASES 97\\nIt will be noticed in this case that the instrument reads\\nastigmatism with the rule in the right eye, and astigmatism\\nagainst the rule in the left eye, while it was just the reverse\\nin the preceding case.\\nThis is due to the fact that in each case we started at\\n135\u00c2\u00b0 for the primary position (see rule for procedure in such\\ncases, p. 17). A glance at Figs. 48 and 49 will show why\\nthe instrument thus records these cases. In Case XXXIII,\\nright eye, the primary position was at the shortest curved\\nmeridian, 135\u00c2\u00b0, consequently when the meridian at 45\u00c2\u00b0 was\\nreached, the longest curved meridian, the mires separated,\\nsaying astigmatism against the rule while in the left eye\\nthe longest curved meridian was at 135\u00c2\u00b0, the primary posi-\\ntion, and when the mires were turned to the secondary position,\\n45\u00c2\u00b0, the shortest curved meridian, they overlapped, saying\\nastigmatism with the rule. Now in Case XXXIV, right\\neye, the longest curved meridian was at 135\u00c2\u00b0, consequently\\nwhen the mires were turned to 45\u00c2\u00b0, the shortest curved\\nmeridian, they overlapped, saying astigmatism with the\\nrule while in the left eye the shortest curved meridian\\nwas at 135\u00c2\u00b0, and the longest curved meridian at 45\u00c2\u00b0, there-\\nfore the instrument read astigmatism against the rule, begin-\\nning with 135\u00c2\u00b0 as the primary position.\\nTest cards and trial lenses.\\nR. V.= 2Vo -I^W. 2.50D. 4- 2.75 D. cyl., 45\u00c2\u00b0.\\nL. V. 2 A 1^ W. 2 D. 2.75 D. cyl., 135\u00c2\u00b0.\\nReads Jaeger No. 1 from 7 to 12 inches.\\nOphthalmoscope. H. 8 D. at 135\u00c2\u00b0 and 5 D. at 45\u00c2\u00b0 right\\neye; H. 8D. at 45\u00c2\u00b0 and 5 D. at 135\u00c2\u00b0 left eye,\\nA second test resulted in the patient accepting exactly\\nthe same glasses as at the first, and they were accordingly\\nordered. She has worn these glasses but a few weeks, but\\nas they have relieved her headaches, and enabled her to do", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0115.jp2"}, "116": {"fulltext": "98\\nTHE REFRACTIOX OF THE EYE\\ncontinuous fine needlework, it is fair to presume they will be\\nof permanent benefit.\\nCase XXXV. Astigmatism against the rule in one eye and\\nwith the rule in the other; Marked asthenopia; Relief ivith glasses.\\nApril 24, 1895, Mr. C. C, aged forty-seven years, in mod-\\nerately good health, has been unable to get a suitable glass,\\nand that is why he consulted me to-day. The patient re-\\nceived a blow on his right eye mth a rubber ball when he\\nwas a child, and has never seen very well with that eye since.\\nOphthalmometer. Astigmatism against the rule, .50 D., axis\\n155\u00c2\u00b0 -h or Qo\u00c2\u00b0 right eye astigmatism with the rule, .75 D.,\\naxis 105\u00c2\u00b0 -f or 15\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nI^- f* l*^^-+l ^.+1 D. cyl., 155\u00c2\u00b0.\\nL. Y. II fl W. .50 D. .25 D. cyl., 105\u00c2\u00b0.\\nReads Jaeger Xo. 1 at 8 inches with 1.50 Ds. added to\\ncorrect the presbyopia.\\nR. E\\nL. E.\\nFig. 50.", "height": "4249", "width": "2805", "jp2-path": "refractionofeye00davi_0116.jp2"}, "117": {"fulltext": "ILLUSTRATIVE CASES 99\\nOphthalmoscope, \u00e2\u0080\u0094K. 2D. at 65\u00c2\u00b0 and ID. at 155\u00c2\u00b0 right\\neye H. 1 D. left eye, the astigmatism being too small to\\nestimate with the ophthalmoscope.\\nThe patient accepted the same glasses on a second test that\\nhe accepted at first, and both reading and distance glasses were\\nordered. These glasses have been entirely comfortable, though\\nhe has used his eyes continuously in the capacity of a teacher.\\nHe was wearing when he came under my care a cylindrical\\nglass at the wrong axis in the right eye, and in the left eye a\\ncylindrical glass four times too strong, which were very good\\nreasons for not having comfortable eyes and good vision.\\nCase XXXVI. Ophthalmometer shows no corneal astigma-\\ntism Patient accepts .25 D. cylindrical glass against the rule\\nin addition to a spherical glass. November 29, 1895, Matilda\\nP., aged ten years, in good general health, has for the last year\\nsuffered from headaches, burning, and soreness in the eyes\\nafter studying for a short time, especially in the afternoon and\\nevening.\\nOphthalmometer. Showed no corneal astigmatism what-\\never. The lines dividing the mires into halves were straight\\nwith each other in all positions, and there was no overlapping\\nor separation of the images after they were once approximated.\\nTest cards and trial lenses.\\nR. V. |0- 1^ W. 1 D. .25 D. cyl., 180\u00c2\u00b0.\\nL. V. 1^ 1^ W. 1 D. .25 D. cyL, 180\u00c2\u00b0.\\nReads Jaeger No. 1 from 4 to 12 inches.\\nOphthalmoscope. H. 2D. in each eye. The astigmatism\\nwas too small in amount to be estimated with the ophthalmo-\\nscope.\\nA mild astringent wash was ordered for a conjunctivitis\\nthat was present, and the patient directed to return in a week\\nfor a second test. This test resulted in the patient accepting", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0117.jp2"}, "118": {"fulltext": "100 THE REFRACTION OF THE EYE\\nthe same glasses exactly as at the first, and they were ordered.\\nThe patient has been relieved of her headaches and eye symp-\\ntoms. About eighteen months after the glasses were ordered\\nthe patient returned, complaining that her eyes felt tired.\\nWith a tonic she was relieved of all eye trouble and without\\nthe change of glasses, and she continues her studies with com-\\nfort to date, October, 1898.\\nCase XXXVII. The ophthalmometer shows no corneal\\nastigmatism; Patient accepts -50 D. cylindrical glass against\\nthe rule. July 19, 1895, Miss J. H. M., aged fifty years, in\\ngood general health, consults me on account of pain in the\\neyes and blurring of the vision on doing close work. She has\\nworn glasses for seven years, but they have not been satisfac-\\ntory.\\nOphthalmometer. No corneal astigmatism.\\nTest cards and trial\\nE. V. =|^:ffW.H-.25D. .50D. cyl.,180\\nL. V. f^: f|W. .50 D. .50 D. cyl., 180\u00c2\u00b0.\\nReads Jaeger No. 1 at 8 inches, with a 2 D.s added to\\ncorrect her presbyopia.\\nOphthalmoscope. H. 1 D. at 90\u00c2\u00b0 and .50 D. at 180\u00c2\u00b0 in each\\neye.\\nAfter one test I prescribed the glasses both for distance\\nand for reading. Both have been worn for three years with\\nentire relief from asthenopia.\\nIt will be noticed that the ophthalmometer read negative in\\nthe last two cases, or at least it showed no corneal astigmatism;\\nand that in the first case, XXXVI, but +.25 D. cyl. against\\nthe rule was accepted while in the second case, XXXVII,\\n-I-.50 D. cyl. against the rule was accepted, the customary\\namount in cases where there is no corneal astigmatism present.\\nThe difference in the strength of the cylindrical glasses", "height": "4257", "width": "2789", "jp2-path": "refractionofeye00davi_0118.jp2"}, "119": {"fulltext": "THE INFLUENCE OF AGE ON ASTIGMATISM\\n101\\naccepted by these two patients may be accounted for in part,\\nperhaps, by the fact that in Case XXXVI the patient is a\\nchild, in which case the lens is more elastic, the ciliary muscle\\nstronger and possessed of\\nmore tonicity than in the\\nolder patient, and the mus-\\ncle acting in an irregular\\nway, as it is known to do\\nsometimes, part of the len-\\nticular astigmatism may\\nbe corrected. In Case i^o\\nXXXVII, however, the\\npatient is presbyopic, the\\nlens less elastic, the cili-\\nary muscle weakened, and,\\ntherefore, not so likely to\\ncorrect any of the astigma- pj^. 5^^\\ntism by its irregular action.\\nI am not unmindful of the fact that lenticular astigmatism\\nis usually ascribed to a tilting position of the lens. But, grant-\\ning this, still the ciliary muscle might, by its irregular action,\\ncorrect part of the astigmatism.\\nI beg to be distinctly understood, however, that I do not\\nadvance this idea the influence of age on the accommodation\\nto account for the discrepancies, sometimes present, in the\\nreadings of the ophthalmometer and the glasses accepted by\\nthe patient. I believe it accounts at times for a very small\\npart of the discrepancy. To the more or less tilting of the\\nlens must be ascribed the chief differences in amount in the\\nlenticular astigmatism present. Usually it amounts to just\\n.50 D., but it may be more or less, and at times is absent alto-\\ngether. Hence the variations that we come across in practice,\\nand which should not disturb us if only a little judgment and\\ncommon sense are used in accounting for and correcting same.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0119.jp2"}, "120": {"fulltext": "102\\nTHE REFRACTION OF THE EYE\\nCase XXXVIII. Astigmatism with the rule, .25 D. Patient\\naccepts 50 D. cylindrical glass against the rule with relief from\\nmarked asthenopia. September 18, 1896, Joseph R., aged forty-\\ntwo years, in good health, has worn glasses for six years. He\\nsuffers from headaches, has dazzling sensations before the eyes,\\nand blurring of vision after using his eyes for a short time.\\nOphthalmometer. Astigmatism with the rule, .25 D., axis\\n105\u00c2\u00b0 or 15\u00c2\u00b0 right eye astigmatism with the rule, .25 D.,\\nR. E.\\nL. E.\\nFig. 52.\\naxis 90\u00c2\u00b0 or 180\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nR. V. 1^ 1^ W. .50 D. .50 D. cyl., 15\u00c2\u00b0.\\nL. V. f^ If W. .50 D. .50 D. cyl., 180\u00c2\u00b0.\\nReads Jaeger No. 1 at 8 inches with -h .50 D.s added to\\ncorrect his presbyopia.\\nOphthalmoscope. H. 1 D. at 105\u00c2\u00b0 and H. .50 D. at 15\u00c2\u00b0 right\\neye; H. 1 D. at 90\u00c2\u00b0 and H. .50 D. at 180\u00c2\u00b0 left eye.", "height": "4227", "width": "2698", "jp2-path": "refractionofeye00davi_0120.jp2"}, "121": {"fulltext": "ILLUSTRATIVE CASES 103\\nThe second test resulted in the patient accepting exactly\\nthe same glass as on the first test. Both distance and reading\\nglasses were ordered, and the patient has used his eyes with\\nmore comfort than ever before. In fact, has scarcely any\\ntrouble, though he uses his eyes steadily.\\nIn this case, while the ophthalmometer read astigmatism\\nwith the rule, .25 D., the patient accepted .50 D. cylindrical\\nglass against the rule. This is to be accounted for, I think, by\\nthe presence of .75 D. of lenticular astigmatism. The corneal\\nastigmatism of .25 D. neutralized that amount of the lenticular\\nastigmatism, leaving .50 D. of it to be corrected by the glass\\nwhich the patient accepted.\\nCase XXXIX. Ophthalmometer shows corneal astigmatism\\nwith the rule^ .25 D. Patient accepts this amount exactly^ indi-\\ncating no lenticular astigmatism whatever, May 9, 1895, J. E. H.,\\naged twenty-one years, in good health, has worn glasses for the\\nlast four years, but suffers continually with pains in the eyes,\\nheadaches, and nervousness. He is a bookkeeper, and the strain\\non his eyes is great.\\nOphthalmometer. Astigmatism with the rule, .25 D., axis\\n105\u00c2\u00b0 or 15\u00c2\u00b0- right eye; .25 D., axis 75\u00c2\u00b0 or 165\u00c2\u00b0- left\\neye.\\nTest cards and trial lenses.\\n11 ff W- -2^ cyl., 105\u00c2\u00b0.\\nL. V. 1^ ff W. 50 D. .25 D. cyl., 75\u00c2\u00b0.\\nReads Jaeger No. 1 at 5 inches.\\nOphthalmoscope. H. ID. in each eye.\\nOn a second test, the same glass was accepted, and was\\nordered. With this glass he could follow his calling as a book-\\nkeeper, with comfort. As the patient is a friend, I see him\\nfrequently, and he tells me he has none of his old symptoms.\\nHe has worn the glasses for two and one-half years.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0121.jp2"}, "122": {"fulltext": "104\\nTHE REFRACTIOX OF THE EYE\\nCase XL. Astigmatism with the rule, .25 D.; Patient accepts\\n,50 D. cylindrical glass against the rule, in combination with\\n2 D.s Latent hypermetropia of 2 D. left uncorrected Marked\\nasthenopia; Relief with glasses. As regards the astigmatism,\\nthis case is similar to Case XXXVIII; that is, the corneal\\nastigmatism of .25 D. is more than neutralized by the lenticu-\\nlar astigmatism, leaving .50 D. of lenticular astigmatism to be\\ncorrected by a cylindrical glass.\\nR. E.\\nFig. 53.\\nL. E.\\nMay 29, 1894, William E., aged twenty years, in good health,\\nfamily history good, has been troubled with his eyes since a\\nchild. Has headaches, and pains in the eyes after close work\\nof any kind. He fitted himself to glasses five years ago,\\nH- 1 D.s, but they have not been satisfactory.\\nOphthalmometer, Astigmatism with the rule, .25 D., axis\\n105\u00c2\u00b0 or 15\u00c2\u00b0 right eye 25 D., axis 75\u00c2\u00b0 or 165\u00c2\u00b0 left\\neye.", "height": "4248", "width": "2698", "jp2-path": "refractionofeye00davi_0122.jp2"}, "123": {"fulltext": "ILLUSTRATIYE CASES 105\\nTest cards and trial lenses.\\nR. V. 1^ ff W. 1.50 D. .50 D. cyl., 15\u00c2\u00b0.\\nL. V. If ff W. 1.50 D. .25 D. cyl., 165\u00c2\u00b0.\\nReads Jaeger No. 1 at 7 inches.\\nOphthalmoscope, \u00e2\u0080\u0094YL. 4.50 D. at 105\u00c2\u00b0 and 4 D. at 15\u00c2\u00b0 right\\neye H. 4.50 D. at 75\u00c2\u00b0 and 4 D. at 165\u00c2\u00b0 left eye.\\nOn account of the large amount of latent hypermetropia\\npresent in this case, I gave him three tests, each time correct-\\ning the astigmatism in each eye separately then I placed equal-\\nstrength spherical glasses in front of each eye at the same\\ntime, beginning with .25 D., and gradually increased their\\nstrength up to 2 D., which were as strong as the patient would\\naccept. This spherical glass, in conjunction with the cylin-\\ndrical ones gave him vision, and they were ordered. Al-\\nthough 2 D. of latent hypermetropia remain uncorrected, these\\nglasses have been worn for two and one-half years with entire\\nrelief from his asthenopic symptoms. In passing, it might be\\nremarked that there was no insufficiency of any of the ocular\\nmuscles, and no tendency to squint.\\nCase XLI. Astigmatism with the rule., 1.50 D. in the\\nright eye., and 2 D. in the left., with 2 D. hypermetropia Fitted\\nivith glasses several times under a mydriatic^ with hut little benefit\\nComplete relief with glasses fitted hy the aid of the ophtlialmome-\\nter without any mydriatic. I report this case in connection\\nwith the one preceding, to show that it is unnecessary to make\\nuse of mydriatics in the great majority of cases of compound\\nhypermetropic astigmatism, and that a mj driatic may be of\\nharm, as it proved in this case.\\nJune 4, 1896, J. A. R., aged thirty years, is in fairl} good\\nhealth, bat has very poor digestion and is not strong.i Has\\nhad one sister and one brother who died of consumption. The\\n1 At this writing, October, 1808, I learn the doctor has developed con-\\nsumption.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0123.jp2"}, "124": {"fulltext": "106 THE refractio:n of the eye\\npatient is a practicing physician in the West. For the last\\nseven years his eyes have been a source of great annoyance to\\nhim. In fact, he has not been able to read or write for more\\nthan a few minutes at a time until a severe neuralgic pain\\nwould come in the eyes and forehead, so intense that he would\\nhave to stop his work. He says this pain was so great at\\ntimes that it felt as if his eyes were being drawn out of his\\nhead. His eyes have been tested by competent men at least one-\\nhalf dozen times under the influence of a mydriatic, but none\\nof the glasses prescribed gave him anything more than partial\\nrelief, and then only for a short time. He has suffered greatly\\nfrom photophobia, and of two oculists of this city whom he\\nconsulted besides myself, one was of the opinion that his chief\\ntrouble was hypersesthesia of the retina, and advised no\\nchange of glasses from those he was already wearing. The\\nother oculist whom he consulted, tested his eyes without the\\nuse of a mydriatic. His test and my own, made indepen-\\ndently, agreed exactly in one eye, and differed but .25 D. in\\nstrength in the spherical glass in the other eye. No muscle\\ninsufficiencies were present.\\nOphthalmometer. Astigmatism with the rule, 1.50 D.,\\naxis 90\u00c2\u00b0 or 180\u00c2\u00b0 right eye 2 D., axis 90\u00c2\u00b0 or 180\u00c2\u00b0\\nleft eye.\\nTest cards and trial lenses.\\nR. V. 1^ ff W. .50 D. 1.25 D. cyl., 90\u00c2\u00b0.\\nL. V. ^Yo f* W. .50 D. 1.75 D. cyL, 90\u00c2\u00b0.\\nReads Jaeger No. 1 at 6 inches.\\nOphthalmoscope. Yi. 1.50 D. at 90\u00c2\u00b0 and 2.50 D. at 180\u00c2\u00b0\\nright eye H. 1.50 D. at 90\u00c2\u00b0 and 3 D. at 180\u00c2\u00b0 left eye. Be-\\nsides a slight hypereemia of the retina, the fundus was normal\\nin each eye.\\nSecond test: the ophthalmometer read the same as on the\\nfirst test.", "height": "4260", "width": "2698", "jp2-path": "refractionofeye00davi_0124.jp2"}, "125": {"fulltext": "ILLUSTRATIVE CASES\\nTest cards and trial lenses.\\n107\\nR. V.\\n20\\n30\\n20\\nTO\\nW. 1 D. 1.25 D. cyl., 90\u00c2\u00b0.\\nL. V. f^ W. 1.25 D. -H 1.75 D. cyl., 90\u00c2\u00b0.\\nReads Jaeger No. 1 at 6 inches.\\n1:80\\nFig. oi.\\nOphthalmoscope. Shows the same as at the first test.\\nA third test resulted in the patient accepting exactly the\\nsame glasses as on the second test, and they were ordered.\\nThese glasses gave him entire relief from his asthenopic symp-\\ntoms, and he was able to use his eyes with comfort for long\\nhours for the first time in seven years. It is now more than\\ntwo years since he was ordered these glasses, and they are still\\nsatisfactory.\\nHe was wearing when he came to see me 1.75 D. .75 D.\\ncyl., 90\u00c2\u00b0 right eye, and 1.75 D. 1.25 D. cyl., 90\u00c2\u00b0 left eye.\\nAtropine in the hands of a half dozen competent men had\\nbeen a failure in his case, simply because they overfitted the\\nspherical error and underfitted the astigmatic error.\\nRoosa, long ago, pointed out the fact that in young sub-", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0125.jp2"}, "126": {"fulltext": "108 THE REFRACTION OF THE EYE\\njects we may often leave one, two, and in some cases even as\\nmuch as three, diopters of latent hypermetropia uncorrected\\nwithout harm. Especially, I think, in those cases where the\\nastigmatism is large in amount and the latent hypermetropia\\nsmall or only moderately large in amount, it is safe to let the\\nlatent hypermetropia go uncorrected. The younger the subject,\\nthe more latent hypermetropia may be left without harm. The\\nfollowing is a good example of this class of cases.\\nCase XLII. Astigmatism of large amount, with moderately\\nlarge amount of latent hypermetropia^ which latter was left uncor-\\nrected; Complete relief of the asthenopia hy correction of the astig-\\nmatism. October 6, 1893, Alma S., aged twenty-four years,\\nin good health, has had trouble with her eyes since childhood,\\nbut has never had them examined. Her eyes pain and her\\nhead aches after she uses the eyes for any close work in fact,\\nshe cannot use the eyes for more than a short time without\\nresting them, particularly in the evening.\\nOphthalmometer. Astigmatism with the rule, 5 D., axis\\n60\u00c2\u00b0 or 150\u00c2\u00b0 right eye 5 D., axis 105\u00c2\u00b0 or 15\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nf F f^ 4.25 D. cyl., 60\u00c2\u00b0.\\nL. V. f^ 1^ W. 4.25 D. cyl., 105\u00c2\u00b0.\\nReads Jaeger No. 1 at 6 inches.\\nOphthalmoscope. Yi. 2.50 D. at 60\u00c2\u00b0 and 6.50 D at 150\u00c2\u00b0\\nright eye H. 1.50 D. at 105\u00c2\u00b0 and 6 D. at 15\u00c2\u00b0 left eye.\\nOn a second test the patient accepted exactly the same\\nglasses as at the first test, and they were ordered. They have\\nbeen worn constantly since, with relief of the asthenopic symp-\\ntoms from which she suffered. In this case a latent hyper-\\nmetropia of about 2 D. was left uncorrected in each eye.\\nWhile these last few cases have been given to emphasize\\nthe fact that it is not necessary to use a mydriatic in the great\\nmajority of cases, even where there is considerable amount of", "height": "4257", "width": "2807", "jp2-path": "refractionofeye00davi_0126.jp2"}, "127": {"fulltext": "SPASM OF ACCOMMODATIOI!^\\n109\\nlatent hypermetropia present, yet there are exceptional cir-\\ncumstances under which a mydriatic is necessary in order to\\nfit glasses. I refer to spasm of accommodation.\\n150\\nR. E.\\nL. E.\\nFig. 55.\\nSpasm of Accommodation\\nSpasm of accommodation may be present in any form of\\nerror of refraction, but it is met with more frequently in\\nhypermetropia, hypermetropic astigmatism, and mixed astig-\\nmatism, than in myopic cases. Fortunately, spasm of accom-\\nmodation is a comparatively rare condition, and the cases\\nwhere it is necessary to use a mydriatic to suspend the\\naccommodation are very few.^\\nIn support of this statement the reader is referred to\\npapers by Roosa,^ George J. Bull,^ of Paris, myself, and to\\n1 Of course strabismus cases are here excluded. They will be discussed in\\na separate chapter.\\n2 Trans. Med. Soc, state of New York, February, 1891.\\nOphthalmic Beview, London, September, 1895.\\nNew York Medical Journal, September 10 and October 8. 1892, and June\\n20, 1896.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0127.jp2"}, "128": {"fulltext": "110 THE REFRACTION OF THE EYE\\nthe writings of American and European oculists in the last\\nfew years.\\nLet me, also, emphasize the fact that it is not necessary to\\nuse a mydriatic in every case of spasm of accommodation for,\\nin many cases of spasm of accommodation, if the cause for it is\\nfound out and removed, the spasm disappears. Two questions\\nof importance are to be considered in discussing spasm of\\naccommodation first, how to recognize it second, how to\\ntreat it, especially in regard to fitting glasses.\\nHotv to recogni?:e spasm of accommodation. The most im-\\nportant of the subjective symptoms are (1) Sudden variability\\nin vision in reading the test cards for distant vision. For\\nexample, testing one eye at a time, the patient reads all of the\\nletters on the Snellen card down to and including the J-\u00c2\u00a7- line,\\nwhen suddenly the letters fade out, and the patient is not able\\nto read more than y2_o_ perhaps. Allow the patient to rest a\\nmoment with the eyes closed, then repeat the test, and the\\nsame thing will likely happen again. This condition may be\\npresent in only one eye, but usually it is present in both, if\\npresent at all. This sudden failure of the vision is evidently\\ndue to sudden contraction or spasm of the ciliary muscle,\\nwhich allows the crystalline lens to expand, and the eye to\\nbecome temporarily myopic (false or spasmodic myopia).\\nThis condition, of course, makes the distant vision bad.\\n(2) Changeableness in appearance of the lines on the clock-dial.\\nFor instance, say we have a case of simple hjqDcrmetropic astig-\\nmatism with the rule, and a tendency to spasm of accommoda-\\ntion. This patient when he first looks at the clock-dial may\\nsee the horizontal lines plainest (as he should if no spasm of\\naccommodation was present), but in a moment the vertical\\nlines appear plainest and the horizontal lines become dim.\\nEvidently in such case the spasm of the ciliary muscle has con-\\nverted the simple hypermetropic astigmatism into a myopic\\nastigmatism with the rule, for in myopic astigmatism with the", "height": "4263", "width": "2795", "jp2-path": "refractionofeye00davi_0128.jp2"}, "129": {"fulltext": "SPASM OF ACCOMMODATION^ HI\\nrule the vertical lines are seen plainest. (3) A sense of con-\\ntraction of drawing in the eyeball is felt. (4) Variability in\\nthe glasses accepted by the patient during the test, e.g., a\\npatient accepts a plus glass one minute and in the next refuses\\nit, or, perhaps, accepts a minus glass, quickly changing from\\none to the other or, he may accept a strong plus glass one\\nminute and only a weak one the next.\\nThe objective symptoms are (1) Where the ophthalmo-\\nscopic examination shows the refractive condition of the eye\\nto be widely different from the glasses accepted on subjective\\nexaminations. For instance, the patient has accepted 1 D.\\nspherical glasses when the ophthalmoscope shows him to be\\nhypermetropic by 5 D. Or, say the patient has accepted\\nID. spherical glasses when the ophthalmoscope shows him\\nto be actually hypermetropic. Not infrequently the patient\\nwill relax his spasm of accommodation under an ophthalmo-\\nscopic examination when he will not under a subjective exam-\\nination. This I think due chiefly to the fact that under an\\nophthalmoscopic examination the patient is in a dark room,\\nwith pupils dilated, and looking in the distance at nothing in\\nparticular, having nothing, therefore, to stimulate his accom-\\nmodation while, under a subjective examination, the patient\\nis looking intently at letters, trying to figure them out, and\\nthis of itself many times incites the ciliary muscle to action.\\n(2) Where the retinoscope shows sudden changes in the\\nrefractive condition of the eye, perhaps indicating hyperme-\\ntropia one instant and myopia the next, and where the glasses\\naccepted by the retinoscopic test do not give uniform good\\nvision. (3) In cases of astigmatism where the glasses\\naccepted vary widely from, the reading of the ophthalmometer,\\nit is often an indication of spasm of accommodation.\\nThe above are the chief symptoms of spasm of accommo-\\ndation, and, as a rule, the condition is easily recognized by\\nthem, many times by means of only one or two of them.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0129.jp2"}, "130": {"fulltext": "112 THE REFRACTION OF THE EYE\\nOf the subjective symptoms, the sudden change in the acute-\\nness of vision is the most constant and reliable one and of\\nthe objective symptoms, that discovered by the ophthalmo-\\nscope is the most reliable one.\\nMow to overcome sjjasm of accommodation. When once satis-\\nfied that there is a spasm of accommodation, or a tendency\\nto it, I look for the cause, and try to remove that, before I\\nhastily resort to the use of some mydriatic. For, even though\\nwe do use a mydriatic and fit the patient, the patient is often\\nunable to wear the glasses unless the cause of spasm is gotten\\nrid of. Unless, indeed, as has been recommended and prac-\\nticed by some oculists in this country, atropine is continued\\nfor weeks after the glasses have been fitted, which, in my\\nopinion, is altogether bad practice. The much better plan is\\nto seek for and remove the cause. Failing in that, then\\nmydriatics are called for, but not until then. In exceptional\\ncases, no apparent cause can be discovered to account for\\nspasm of accommodation.\\nSome of the most prominent causes of spasm of accom-\\nmodation are (1) conjunctivitis (2) insufficiency of the\\ninternal recti muscles (3) contusion (4) sympathetic irrita-\\ntion, though many times contusion and sympathetic irritation\\nare accompanied with paresis of accommodation (5) gener-\\nalized spasmodic affections (6) overwork of the eyes\\n(7) hypersesthesia of the retina (8) beginning the test for\\nglasses with minus glasses (9) idiopathic cases.\\nThese are the chief causes of spasm of accommodation.\\nMany times, where the test for glasses at first has been-\\nunsatisfactory, and a tendency to spasm, or actual spasm, of\\naccommodation was present, I have succeeded in fitting glasses\\nby first treating the lids for a week or ten days with a\\nmild astringent wash. A conjunctivitis of a mild type will\\noften cause enough irritation of the ciliary muscle to render\\na test for glasses unsatisfactory. Again, where the patient", "height": "4265", "width": "2792", "jp2-path": "refractionofeye00davi_0130.jp2"}, "131": {"fulltext": "ILLUSTRATIVE CASES 113\\nhas been using the eyes excessively for a day or two\\nbefore coming for a test, it is often necessary to make him\\nrest the eyes or use them easily for a day or two, before\\ngiving the final test. In hypersesthesia of the retina, shaded\\nglasses worn for a few days before the test is desirable. If\\ninsufficiency of the internal recti muscles is present, a week\\nor two of treatment with strych. sulphate, in increasing\\ndoses, with outdoor exercise and rest, will usually suffice to\\nrelieve it, and leave the eyes in condition for testing.\\nSo with the other causes of spasm of accommodation\\nwhen present, I try to remove them. If no apparent cause\\nis to be found, and if the second test for the glasses is not\\nsatisfactory, and does not substantially agree with the first,\\nI do not hesitate to use a mydriatic, and a strong one. Sco-\\npolamine and atropine are the two I employ. The method\\nof their use I have already pointed out in the first part of\\nthis chapter.\\nI now give some cases illustrative of the condition of\\nspasm of accommodation.\\nCase XLIII. Compound hypermetropic astigmatism toith\\nthe rule; Spasm of accommodation; Amblyopia Atropine used,\\nand but little difference found between the glasses fitted without\\natropine and those fitted under it. June 25, 1891, Gussie L.,\\naged fifteen, is in poor general health. Her eyes have troubled\\nher since six years of age, when she entered school. She was\\nnever able to see the blackboard well, was nervous, and found\\nit hard to sit still for any great length of time. At present\\nshe has headaches, and pains in the eyes on using them for\\nclose work.\\nOphthalmometer. Astigmatism with the rule, 1.50 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 in each eye.\\n1 For the methods of testing the strength of the external ocular muscles, see\\nthe chapter on Strabismus.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0131.jp2"}, "132": {"fulltext": "114 THE REFRACTIOX OF THE EYE\\nTest cards and trial lenses. The lines on the clock-dial\\nwere entirely unsatisfactory as a test.\\nR- V. jVo iVo W. 2 D 1 D. cyL, 180\\nL- V. jVV tVo W. 2 D 1 D. cyL, 180\u00c2\u00b0.\\nDuring the test there were signs of spasm of accommoda-\\ntion, for first one set of lines on the clock-dial would appear\\nplainest, then another set; and the vision at one moment\\nwould be fairly good and the next moment very poor. I\\ntherefore began to test both eyes at once, even for the astig-\\nmatism, and as the ophthalmometer showed it to be exactly\\nthe same in each eye, it was easy to do so. Placing .25 D.\\ncyl., 90\u00c2\u00b0, before each eye, the vision was somewhat improved,\\nand I gradually increased the strength up to -f ID. cyl., the\\nvision improving para passu. With a stronger -f cyl. the vision\\nwas not so good as with the -f- 1 D. cyl., so I stopped at that\\npoint. With the cylindrical glasses in position, weak plus\\nspherical glasses were tried before both eyes at once with\\nimprovement in vision, and they were gradually increased up\\nto 1 D. sphere. Testing in this way both eyes at the same\\ntime, the patient accepted H- 1 D. 1 D. cyl., 90\u00c2\u00b0, and the\\nvision was brought up to f^ in each eye.\\nOphthalmoscope. \u00e2\u0080\u0094YL. 2D. at 90\u00c2\u00b0 and 3.50 D. at 180\u00c2\u00b0 in\\neach eye.\\nAtropia sulphate, solution of four grains to one ounce, was\\nordered instilled, one drop in each eye three times a day for\\nfour days, and then a second test was made.\\nThe ophthalmometer read exactly the same as at the first\\ntest.\\nTest cards and trial lenses.\\nR. V. 2^^ 1^ W. -h 2 D. 1.25 D. cyl., 90\u00c2\u00b0.\\nL. V. 2V0 I* W. 4- 1.50 D. 1.25 D. cyl., 90\u00c2\u00b0.", "height": "4261", "width": "2791", "jp2-path": "refractionofeye00davi_0132.jp2"}, "133": {"fulltext": "ILLUSTRATIVE CASES\\n115\\nOphthalmoscope. H. 2 D. at 90\u00c2\u00b0 and 3.50 D. at 180\u00c2\u00b0 right\\n\u00c2\u00abye H. 1 D. at 90\u00c2\u00b0 and 2.50 D. at 180\u00c2\u00b0 left eye. Retinoscopy\\nconfirmed the other tests.\\nOne week after the test under atropine, the patient was\\nsubjected to a third test. She accepted 1.25 D, 1.25 D.\\ncyL at 90\u00c2\u00b0 right eye, and\\n1 D. 1.25 D. cyL\\nat 90\u00c2\u00b0 left eye, and these\\nglasses were ordered. It\\nwill be noticed that they\\ndiffer but slightly from\\nthe ones that the patient\\naccepted before atropine\\nwas used, that is, when\\nboth eyes were tested at\\nonce. In fact, they differ\\nso little that I believe she\\nwould have been almost,\\nif not quite, as comfort-\\nable with the former as\\nshe is now with the latter, which give her entire relief from\\nher asthenopia. Her poor vision, however, which later I found\\nto be due simply to amblyopia, and the fact of her accepting\\nminus glasses at first when the eyes were tested separately,\\ninduced me to use a mydriatic. Under tonics and outdoor\\nexercise her general health improved.\\nCase XLIV. Compound hypermetropic astigmatism against\\nthe rule; Spasm of accommodation Mild conjunctivitis; Hyper-\\ncesthesia of the retince; Scopolamine used, November 20,\\n1895, Miss C. A. F., aged twenty-two years, in good general\\nhealth, consulted me first for a catarrhal conjunctivitis. She\\nstates that about two years ago she had a very severe inflam-\\nmation in the eyes following measles, and was confined to a\\ndarkened room for five months on account of the light which\\nFig. 56.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0133.jp2"}, "134": {"fulltext": "116 THE REFRACTIOX OF THE EYE\\nhurt her eyes. She had glasses fitted shortly afterward, but\\nher eyes have continued to j^ain her.\\nOphthalmometer. Shows no corneal astigmatism.\\nTest cards and trial lenses.\\nM M -25 D. cyl., 180\u00c2\u00b0.\\nL.V.=|| :|^W. .25D.cyl., 180\u00c2\u00b0.\\nReads Jaeger Xo. 1 at 4 inches.\\nOphthalmoscope. H. ID. in each eye no astigmatism\\ncould be estimated with the ophthalmoscope.\\nAlthough both eyes were tested at the same time, the patient\\nwould not accept any stronger glasses. Xeither was retino-\\nscopy of benefit in fitting the case. During the test the patient\\nwould be able to read at one moment, then the vision would\\nblur and she could not read more than She also complained\\nof drawing sensations in the eyes.\\nScopolamine, -J per cent solution, was instilled, one drop in\\neach eye every five minutes for six successive times, and then\\nafter a wait of half an hour a second test was made.\\nSecond test, under scopolamine.\\nOpfhtJialmometer Xo corneal astigmatism.\\nTest cards and trial lenses.\\n=H I* 1 D. .25 D. cyl., 15\u00c2\u00b0.\\nL- V. f^ 1^ W. 1 D. .25 D. cyl., 165\u00c2\u00b0.\\nOphthalmoscope. Showed the same amount of H. as at the\\nfirst test.\\nThree days later, when the patient was out from under the\\ninfluence of the mydriatic, a third test was made, with the\\nfollowing result\\nR. y. 1^- 14 W. .25 D. .25 D. cyl., 15\u00c2\u00b0.\\nL. v. 1^ 1^ W. .25 D. .25 D. cyl., 165\u00c2\u00b0.", "height": "4265", "width": "2817", "jp2-path": "refractionofeye00davi_0134.jp2"}, "135": {"fulltext": "ILLUSTRATIVE CASES 117\\nThis last glass was prescribed, and the patient had almost\\nimmediate relief from her asthenopia, although it required\\nweeks to relieve the photophobia. In fact, a bright light, as\\nthe glare of tlie sun on the water, still troubles her considerably.\\nCase XLV. Hypermetropia of large amount; Spasm of\\naccommodation Asthenopia; Atropine used Relief with 3 D.\\nof latent hypermetropia left uncorrected. June 16, 1896, Bella\\nK., aged fourteen, in good health, complains of her eyes hurting\\nher when she tries to do close work, and of a drawing sensation\\nin the eyes at times. She has always had weak eyes and\\noften suffers from headaches.\\nOphthalmometer. Astigmatism with the rule, .25 D., axis\\n105\u00c2\u00b0 or 15\u00c2\u00b0- right eye .25 D., axis 75\u00c2\u00b0 or 165\u00c2\u00b0- left eye.\\nTest cards and trial lenses.\\nR. V. f^ ff W. .50 D. .25 D. cyl., 105\u00c2\u00b0.\\nL. y. f^ f^ W. 1 D. .25 D. cyl., 75\u00c2\u00b0.\\nReads Jaeger No. 1 from 4 to 16 inches.\\nOphthalmoscope. H. 3D. in each eye.\\nAs the patient had signs of spasm of accommodation, first\\nbeing able to read well then the vision blurring, sense of con-\\ntraction in the eyes, accepting a weak cylindrical glass and\\nthen refusing it, etc., I decided to use a mydriatic, especially as\\nthe ophthalmoscope showed at least three diopters of hj per-\\nmetropia. Atropine, 4 gr. to 5Tsol., was ordered instilled, one\\ndrop three times a day for three days.\\nSecond test, under atropine.\\nOphthalmometer gave the same reading as at the first test.\\nTest cards and trial lenses.\\nR V -2JL 2 _ w 5 D", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0135.jp2"}, "136": {"fulltext": "118 THE REFRACTION OF THE EYE\\nOphthalmoscope. H. 5 D. right eye; H. 6 D. left eye.\\nThird test, one week later, the patient accepted 2 D.\\nright QjQ and 2.50 D. left eye. These glasses were ordered,\\nand though they left about three diopters of hypermetropia in\\neach eye uncorrected, yet they have been worn with comfort\\nand relief from asthenopic symptoms for a period of two years.\\nThis patient would not relax the accommodation when both\\neyes were tested at once, and even after being under atropine\\nand coming out she yet had 3 D. of latent hypermetropia.\\nNevertheless, since with 2 D. right and 2.50 D. left the\\nvision was and steady, without signs of spasm of ac-\\ncommodation, I left the latent hypermetropia to take care of\\nitself.\\nI make this distinction between spasm of accommodation and\\nlatent Kypermetropia. In spasm of accommodation the vision is\\nvariable, that is, it changes from one moment to another, often\\nwith sensations of drawing in the eyes, and the ophthalmoscopic\\nand retinoscopic examinations show the refraction to vary\\nwhile in latent hypermetropia the ciliary muscle is able to and\\ndoes correct steadily and without irregular action that portion\\nof the total hypermetropia which is latent. As long as the\\nciliary muscle can do this with comfort and without strain, the\\nlatent hypermetropia remains practically the same, at least does\\nnot vary suddenly, and the subjective examinations do not\\ndiscover it, unless when for some special reason we use a\\nmydriatic. As the patient grows older, however, or becomes\\nill or overworked, the ciliary muscle may not be able to keep\\nup its steady action, and begins to manifest signs of fatigue and\\nto act irregularly, or with spasmodic action, if you please, with\\nthe result of variability in vision, a sensation of drawing in the\\neyes, headaches, etc. It is at this time that aid to the ciliary\\nmuscle is called for and should be given, but as long as an eye\\ncan work with comfort, and without bother to the patient, I\\nbelieve it good policy to let it alone.", "height": "4246", "width": "2698", "jp2-path": "refractionofeye00davi_0136.jp2"}, "137": {"fulltext": "ILLUSTRATIVE CASES 119\\nI shall give here also a single case of spasm of accommoda-\\ntion occurring in simple hypermetropic astigmatism but for\\ncases of spasm of accommodation occurring in myopia, myopic\\nastigmatism, and mixed astigmatism, I shall give them when\\ntreating those subjects.\\nCase XL VI. Simple hypermetropic astigmatism; Spasm of\\naccommodation; Marked asthenopia; Minus cylindrical glasses\\naccepted without atropine and perfect vision obtained; Plus\\ncylindrical glasses accepted under atropine and perfect vision.\\nApril 5, 1892, Herminia T., aged nineteen years, in good health,\\nhas been troubled with her eyes for the last four years, in fact,\\nmore or less ever since she entered school. She cannot read\\nor sew for any great length of time without getting pain in the\\neyes, and if she persists in her work her head aches. Some\\nslight injection of the conjunctiva.\\nOphthalmometer. Astigmatism with the rule, 1.25 D., axis\\n90\u00c2\u00b0 4- or 180\u00c2\u00b0 each eye.\\nTest cards and trial lenses. The vertical lines on the clock-\\ndial appeared plainest.\\nR. V. 1^ If W. .75 D. cyl., 180\u00c2\u00b0.\\nL. V. If ff W. .75 D. cyl., 180\u00c2\u00b0.\\nReads Jaeger No. 1 from 6 to 15 inches.\\nOphthalmoscope. Emmetropia vertical meridian (90\u00c2\u00b0) and\\nH. .50 D. in horizontal meridian (180\u00c2\u00b0) in each eye.\\nAlthough both eyes were tried at once, the patient would\\naccept nothing but minus glasses. Retinoscopy indicated\\nmyopic astigmatism. A wash was prescribed for the mild\\nconjunctivitis, the patient ordered not to use the eyes so\\nhard, and to report in a week. A second test was given, with\\nexactly the same result as on the first test. Signs of spasm of\\naccommodation were present. Atropine, solution 1 gr. to oi,\\nwas ordered instilled, one drop three times a day for three\\ndays.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0137.jp2"}, "138": {"fulltext": "120\\nTHE REFRACTION OF THE EYE\\nTest under atropine ophthalmometer read the same as on\\nthe two previous tests.\\nTest cards and trial lenses. The horizontal lines on the\\nclock-dial were seen plainest now.\\nV- 1^ ft w- cyi-. 90\u00c2\u00b0.\\nL. V- If ff cyi-^ 90\u00c2\u00b0.\\nA week later, when the effect of atropine was out of the\\neye, the patient again accepted .75 D. cylindrical glass, axis\\nFig. 57.-\\nShowing how a simple minus cylindrical glass can convert a simple hyper-\\nmetropic astigmatism into simple hypermetropia.\\n90,\u00c2\u00b0 in each eye, and it was ordered. These glasses have been\\nworn for more than four years, and with relief from her asthe-\\nnopic symptoms.\\nIn some cases of simple hypermetropic astigmatism a patient\\nwill accept a minus cylindrical glass and get relief from all\\nasthenopic symptoms. This is to be explained, I think, by\\nthe fact that the patient, in accepting a simple myopic cylin-\\ndrical glass, converts the simple hypermetropic astigmatism\\ninto a simple hypermetropia (see Fig. 57). By so doing, the", "height": "4246", "width": "2789", "jp2-path": "refractionofeye00davi_0138.jp2"}, "139": {"fulltext": "ILLUSTRATIVE CASES 121\\nciliary muscle can then act in its entire circumference and cor-\\nrect the simple hypermetropia of small amount with ease and\\nwithout fatigue whereas it could not correct an equal amount\\nof simple hypermetropic astigmatism, because, in that instance,\\nit would be compelled to contract irregularly, and in that way\\ncause asthenopia or painful vision.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0139.jp2"}, "140": {"fulltext": "CHAPTER V\\nSIMPLE MYOPIC ASTIGMATISM MYOPIA\u00e2\u0080\u0094 SPASMODIC OE EALSE\\nMYOPIA RULE FOR PRESCRIBING NEAR OR READING\\nGLASSES IN HIGH DEGREES OF MYOPIA PRESBYOPIA AND\\nTHE TRANSPOSITION OF GLASSES FROM DISTANCE TO READ-\\nING IN MYOPES WHEN IT IS PRESENT\\nThe ophthalmometer, except in an indirect way already\\ndiscussed in a previous chapter, does not reveal the nature of\\nthe error of refraction. This has to be found out with the\\ntrial case and test cards, the ophthalmoscope and retinoscope.\\nSo in myopia we make the same measurements with the oph-\\nthalmometer as in all other cases. Furthermore, I begin the\\ntest with plus glasses just as I do in all cases, because, not\\nknowing the nature of the error of refraction, it is safe to\\nbegin only with plus glasses. Should the patient prove to be\\nhypermetropic, and minus glasses are tried first, they often\\nincite a spasm of accommodation and are accepted when they\\nshould not be while, if plus glasses are begun with, we can\\nbe sure they will not be accepted by a myope, and we can find\\nthis out by the trial of only two or three glasses and without\\nthe risk of inciting spasm of accommodation. Of course, if\\nthe ophthalmoscope is used before glasses are tried, that\\nindicates the kind of glass to be tried first. As a rule, how-\\never, I prefer not to make an ophthalmoscopic examination\\nuntil I have tried the test cards and trial case, because, if light\\nis thrown into the eyes for any considerable time just before\\ntesting the vision, it often impairs the value of the test.\\nPerhaps before giving illustrative cases it is well to make\\na clear distinction here between true or axial myopia and false\\n122", "height": "4257", "width": "2829", "jp2-path": "refractionofeye00davi_0140.jp2"}, "141": {"fulltext": "THE DIFFERENT FORMS OF MYOPIA\\n123\\nFig. 58. True or axial myopia, par-\\nallel rays focussing in front of the\\nretina, crossing and forming dif-\\nfusion circles on the retina.\\nor spasmodic myopia. True myopia is where the axis of the\\neye is too long, allowing the rays of light to focus in front\\nof the retina (see Fig. 58). This may be small or large in\\namount, according to the increase\\nof length of the eyeball beyond\\nthe length of the emmetropic\\neye, which latter is about 23 mm.\\nWhen the eye becomes elongated\\nrapidly, attended with changes in\\nthe choroid and sclera, with poste-\\nrior staphyloma, etc., we call this\\nprogressive or malignant myopia.\\nFalse myopia is nothing more than a spasm of the ciliary or\\nfocussing muscle. To illustrate, say the patient is emmetropic,\\nbut from some cause the ciliary muscle is overacting. By so\\ndoing the eye is rendered myopic by the lens becoming thicker,\\nand causing the rays to focus in front of the retina. Further-\\nmore, this patient would accept minus glasses with improve-\\nment in vision, as long as this spasm of accommodation lasted.\\nFalse myopia may be present even in hypermetropia, the\\nfocus being changed from back of the retina to the front of\\nit by the spasm of accommodation.\\nAgain, false myopia may be present\\nin the same eye with true myopia,\\nthat is, the spasm of accommoda-\\ntion increases the true myopia.\\nIt is altogether important to\\nrecognize the difference between\\ntrue and false myopia for, while\\nthe true myopia should be care-\\nfully corrected, false myopia should never have a gla^s pre-\\nscribed for it, but its cause should be looked for and reme-\\ndied, if possible, upon wliich it disappears and requires no\\nfurther treatment.\\nFig. 59. False myopia in an em-\\nmetropic eye, due to spasm of\\naccommodation. Dotted line\\nshows false focus.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0141.jp2"}, "142": {"fulltext": "124\\nTHE REFRACTIOX OF THE EYE\\nFig. 60. Curvature myopia,\\nwhere the length of the eye-\\nball is normal, but the cor-\\nnea is too much curved.\\nOf curvature myopia it is hardly worth while to speak, more\\nthan to say that such a thing exists. It is due to excessive\\ncurvature of the cornea, and not\\nto lengthening of the eyeball (see\\nFig. 60).\\nIt is a rare error of refraction,\\nand when present is usually due to\\nsome pathological condition, conical\\ncornea, staphyloma of the cornea,\\netc., for which conditions glasses\\nare of but little benefit.\\nOf the rule of procedure in giving distance and reading\\nglasses in high degrees of myopia, and of the transposition of\\nglasses in presbyopia in myopic cases, I shall speak later in this\\nchapter, giving appropriate illustrative cases.\\nCase XLVII. Simple myopic astigmatism with the rule;\\nBlepharitis marginalia; Slight asthe^iopia; Relief of blejjharitis\\nwith use of glasses and local treatment. October 26, 1896,\\nCharles Q., aged twenty-nine years, in good health, always had\\npoor vision, and for the last four years his eyelids got red at\\nthe edges when he used his eyes for close work of any kind.\\nThere is but little pain in the eyes, but the lids itch and burn.\\nHe has no headaches.\\nOphthahnometer Astigmatism with the rule, 3 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 in each eye.\\nTest cards and trial lenses.\\nM ff 2.50 D. cyl., 180\u00c2\u00b0.\\nL. V. 1^ ff W. 2.50 D. cyl., 180\u00c2\u00b0.\\nReads Jaeger No. 1 at 12 inches.\\nOphthalmoscope. Myopia 3 D. at 90\u00c2\u00b0 and emmetropia at\\n180\u00c2\u00b0 in each eye.\\nA wash of boracic acid solution was ordered to cleanse the", "height": "4258", "width": "2850", "jp2-path": "refractionofeye00davi_0142.jp2"}, "143": {"fulltext": "ILLUSTRATIVE CASES\\n125\\nlids with twice a day, and an ointment of yellow oxide of\\nmercury, eight grains to one ounce of vaseline, to rub on the\\neyelids at night.\\nTwo weeks later the lids\\nwere very much improved in\\nappearance. A second test for\\nglasses was made, and the pa-\\ntient accepted exactly the same\\nglasses as at the first test.\\nOrdered 2.50 D. cyl., 180\u00c2\u00b0,\\nfor each eye, which have been\\nworn with an entire relief from\\nthe lid trouble.\\nIn this case, the test was\\nbegun with plus cylindrical\\nglasses, just as I do in all\\ncases where the ophthalmome-\\nter indicates astigmatism, but,\\nas vision was made worse, minus cylindrical glasses were im-\\nmediately tried and with improvement in vision.\\nTheir strength was gradually increased up to 2.50 D.,\\nwhen vision was brought up to No minus spherical glasses\\nwere tried in addition to the cylindrical glasses in this case,\\nfor the vision, obtained by the patient with simple cylindri-\\ncal glasses, was proof that no myopia was present in addition\\nto the astigmatism.\\nCase XLVIII. Simple myopic astigmatism with the rule\\nSome amblyopia Relief with glasses. March 23, 1895, J. H. B.,\\naged eighteen years, in good health, complains of poor vision\\nfor distance, and of some difficulty in reading and writing.\\nHe has a tendency to half shut his eyes when he tries to see\\nplainly.\\nOphthalmometer. Astigmatism with the rule, 3.50 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 in each eye.\\nFig. 61. Showing myopia of 3 D. in\\nthe vertical meridian, and emme-\\ntropia in the horizontal meridian.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0143.jp2"}, "144": {"fulltext": "126 THE REFRACTION OF THE EYE\\nTest cards and trial lenses. The vertical lines on the\\nclock-dial are seen plainest in each eye.\\n]R. V. 1^ W. -3D. cyL, 180\u00c2\u00b0.\\nL. V. =f^:f^W. -3D. cyl., 180\u00c2\u00b0.\\nOphthalmoscope. Myopia 3 D. at 90\u00c2\u00b0 and emmetropia at\\n180\u00c2\u00b0 in each eye.\\nOn a second test the patient accepted the same glasses as\\nat first, and \u00e2\u0080\u00943D. cyl., 180\u00c2\u00b0, was ordered for each eye.\\nIn this case, as vision was not brought to with simple\\nminus cylindrical glasses, I suspected myopia to be present in\\naddition to the astigmatism. I therefore tried minus spherical\\nglasses in addition to the cylindrical glasses, but they did not\\nimprove vision any. The ophthalmoscope showed the fundus\\nof each eye to be healthy, so the poor vision was attributed to\\namblyopia. The simple cylindrical glasses have been worn\\nwith comfort for more than three years.\\nCase XLIX. Simple myopic astigmatism with the rule of\\nlarge amount; Amblyopia^ and a mild form of asthenopia:\\nJuly 7, 1892, Frank H., aged eleven years, in good health,\\ncomplains that he has always seen badly, but has not had much\\npain in his eyes. He holds his reading matter entirely too\\nclose to his eyes, and has to squeeze the lids almost together,\\nin order to see even fairly well. He has never worn a glass.\\nOphthalmometer. Astigmatism with the rule, 4.50 D.,\\naxis 105\u00c2\u00b0 or 15\u00c2\u00b0 right eye 4.50 D., axis 75\u00c2\u00b0 or 165\u00c2\u00b0\\nleft eye.\\nTest cards and trial\\nR- V. iVo ltW.-4D. cyl.,15\u00c2\u00b0.\\nL. V. ^-V fi W. 4 D. cyl., 165\\nReads Jaeger No. 1 at 10 inches.", "height": "4265", "width": "2832", "jp2-path": "refractionofeye00davi_0144.jp2"}, "145": {"fulltext": "ILLUSTRATIVE CASES 127\\nOphthalmoscope. Myopia 5 D. at 105\u00c2\u00b0 and emmetropia\\nat 15\u00c2\u00b0 right eye myopia 5 D. at 75\u00c2\u00b0 and emmetropia at 165\u00c2\u00b0\\nleft eye.\\nAs the patient accepted only 4 D. cylindrical glass, it\\nshows that the estimation with the ophthalmoscope of 5 D. of\\nmyopia in the shortest curved meridians was too high by\\n1 D. The fundus of each eye was normal. There was a\\nscleral ring at the temporal side of each disk.\\nA second test, three days later, resulted in the patient\\naccepting the same glasses as at the first test, and they were\\nordered.\\nHere again, as in Case XL VI II. on account of the amblyo-\\npia, vision being brought up to only with simple cylindrical\\nglasses, myopia in addition to the astigmatism was suspected.\\nMinus spherical glasses, therefore, were tried in addition to\\nthe cylindrical glasses but they did not improve vision any.\\nThe somewhat poor vision, was attributed to amblyopia, as\\nthe ophthalmoscope showed the fundi to be normal.\\nCase L. No corneal astigmatism; Patient accepts .50 D.\\ncylindrical glasses against the rule; Relief from asthenopia.\\nApril 24, 1894, James A., aged twenty-three years, in excellent\\nhealth, has been troubled with his eyes for the last two years.\\nAfter using the microscope or ophthalmoscope he has pains in\\nthe eyes, and if he persists in using his eyes, headaches follow.\\nOphthalmometer. No corneal astigmatism wdiatever.\\nTest cards and trial lenses. The horizontal lines on the\\nclock-dial were seen plainest.\\nR. y. |^_: i|W. -.50D. cyl., 90\u00c2\u00b0.\\nL. V. I J ff W. .50 D. cyl., 90\u00c2\u00b0.\\nReads Jaeger No. 1 from 4 to 20 inches.\\nOphthalmoscope. Myopia .50 D. at 180\u00c2\u00b0 and emmetropia\\nat 90\u00c2\u00b0 in each eye.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0145.jp2"}, "146": {"fulltext": "128\\nTHE REFRACTION OF THE EYE\\n\u00e2\u0096\u00a0180\\nA second test resulted in the patient accepting exactly the\\nsame glasses as at the first test, and they were ordered, with\\nconsequent complete relief of his\\nasthenopia.\\nThe retinoscope was used in\\nthis case to advantage, as it in-\\ndicated myopia of a small amount\\nin the horizontal meridian. The\\nlines on the clock-dial were of\\nservice also, as they indicated\\neither hypermetropic astigmatism\\nwith the rule, or a myopic astig-\\nmatism against the rule. Keep-\\ning in mind also the fact that,\\nmost of the time, when there is\\nno corneal astigmatism, there is\\nusually a small amount of lenticu-\\nlar astigmatism against the rule,\\nI began the test with a plus cylin-\\ndrical glass, with the axis at 180\u00c2\u00b0. But it made vision worse,\\nso I tried minus cylindrical glasses at 90\u00c2\u00b0. They improved\\nvision, the patient accepting .50D. cyL, 90\u00c2\u00b0, and getting\\nthe best vision.\\nCase LI. Sim ple myopie astigmatism with the rule in the\\nright eye Lenticular astigmatism against the rule in the left eye^\\nthe ophthalmometer showing no corneal astigmatism Asthenopia\\nRelief with glasses. November 29, 1895, M. L. H., aged\\ntwenty-five years, in good health, is a designer of wall papers,\\nwhich occupation requires very acute vision. The patient com-\\nplains that for the last two months her eyes have ached and\\npained her, and also that her head ached if she persisted in\\nusing her eyes for an hour or two at her work.\\nOphthalmometer. Astigmatism with the rule, ID., axis\\n90\u00c2\u00b0 -f- or 180\u00c2\u00b0\u00e2\u0080\u0094 right eye no corneal astigmatism left eye.\\nFig. 62. Showing myopic astigma-\\ntism against the rule emme-\\ntropia in the vertical meridian\\nand myopia in the horizontal\\nmeridian.", "height": "4259", "width": "2851", "jp2-path": "refractionofeye00davi_0146.jp2"}, "147": {"fulltext": "\u00e2\u0096\u00a0Mi\\nILLUSTRATIVE CASES\\n129\\nTest cards and trial lenses. The lines on the clock-dial\\nwere unsatisfactory.\\nfo-W- ^D. cyl., 180\u00c2\u00b0.\\nL. V. 1^ 1^ W. 50 D. cyl., 90\u00c2\u00b0.\\nReads Jaeger No. 1 from 6 to 12 inches.\\nOphthalmoscope. Myopia ID. at 90\u00c2\u00b0 and emmetropia at\\n180\u00c2\u00b0 right eye; myopia .75 D. at 180\u00c2\u00b0 and emmetropia at 90\u00c2\u00b0\\nleft eye.\\n180\\n180\\nR. E.\\nFig. 63.\\nL. E.\\nThe retinoscope confirmed the ophthalmoscopic examination\\nand the subjective test.\\nA second test was made, and the patient accepting the same\\nglasses as at first, they were ordered. Although one glass is\\nworn at 90\u00c2\u00b0 and the other at 180\u00c2\u00b0, they have given her entire\\nrelief from her asthenopic symptoms. I have seen the patient\\nfrequently since, and she continues to wear the glasses con-\\ntinuously and with comfort.\\nCase LII. Simple myopic astigmatism in one em\\\\ and simple\\nmyopia in the other; Asthenopia; Relief with glasses. May 6,", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0147.jp2"}, "148": {"fulltext": "130 THE REFRACTIOX OF THE EYE\\n1896, E. D., aged thirty-two, in good health, but has noticed\\nsince boyhood that he could not see quite so well as his com-\\npanions when looking at distant objects. For the last six\\nmonths he has experienced pains in the eyes and some frontal\\nheadaches after using his eyes for close work for any consider-\\nable length of time. Some slight redness of the lids present,\\nalso produced by close use of the eyes. He is not of a myopic\\nfamily, although he has one brother who has myopic astigma-\\ntism of small amount. The patient is of the o^^inion that both\\nhe and his brother acquired most of their eye trouble from\\nclose application to books, as neither were compelled to wear\\nglasses until near thirty years of age.\\nOpTithalmometer Astigmatism with the rule, 1.25 D., axis\\n90\u00c2\u00b0+ or 180\u00c2\u00b0- right eye; .50 D., axis 90\u00c2\u00b0+ or 180\u00c2\u00b0- left eye.\\nTest cards and trial lenses.\\nR. y. II -II _ W. .75 D. cyl. 180\u00c2\u00b0.\\nL. Y. f|-:f|-W.-.75D.\\nReads Jaeger No. 1, 41 to 20 inches.\\nOphthalmoscope. Myopia ID. at 90\u00c2\u00b0 and emmetropia at\\n180\u00c2\u00b0 right eye; myopia ID. left eye. There is a crescent of\\nchoroidal pigment at the temporal side of the disk in the right\\neye.\\nSecond test the patient accepted the same glasses as at\\nfirst, and they were ordered for constant wear. This patient\\nhas been under constant observation for more than two years,\\nand the glasses have been worn with entire comfort.\\nI am of the opinion that had there been no astigmatism\\nin the right eye, but a simple myopia, as in the left eye,\\nno glasses would have been required at all, as .75 D. to 1.50 D.\\nof simple myopia rarely calls for a glass, unless the patient\\nwishes to see very clearly for the distance. Very small\\namounts of myopic astigmatism, even so little as .25 D., in", "height": "4252", "width": "2869", "jp2-path": "refractionofeye00davi_0148.jp2"}, "149": {"fulltext": "ILLUSTRATIVE CASES 131\\nexceptional cases when associated with myopia and with slant-\\ning axes, may give rise to asthenopia and call for correction,\\nas is shown by one or two cases reported in the following\\nchapter.\\nCase LIII. Corneal astigmatism with the rule^ .50 D.\\nPatient accepts simple spherical glasses of high power for\\ndistance^ and weaker for reading The rule for giving two\\npairs of glasses in high degrees of myopia considered. Feb-\\nruary 26, 1895, I. G., aged thirty-two years, in good health,\\nhas had poor vision as long as he can remember, that is, from\\n\u00c2\u00abarly childhood. No pain in the eyes or headaches are com-\\nplained of simply poor sight.\\nOphthalmometer. Astigmatism with the rule, .50 D., axis\\n90\u00c2\u00b0 -I- or 180\u00c2\u00b0- in each eye.\\nTest cards and trial lenses.\\n200 50\\nL V 1-^ -sow 11 D\\n200 30 J-J- -L\\nReads Jaeger No. 1 at 8 inches, with 11 D. right eye\\nand 8 D. left eye.\\nOphthalmoscope. Myopia 15 D. right eye, myopia 12 D.\\nleft eye. Excessive pigmentation (choroidal tigre) in each\\neye, but no staphyloma in either. Vitreous clear in both.\\nOn a second test, the patient accepted the same glasses,\\nboth for the distance and the near point, as at the first test,\\nand they were ordered.\\nThe corneal astigmatism of half diopter in this case was\\nneutralized by the lenticular astigmatism, the usual amount of\\nneutralization, and left it as simple myopia to deal with. This\\nmyopia was of so great an amount, however, that two pairs of\\nglasses had to be prescribed, one for distance and the other\\nfor reading, and not, as it will be noted, on account of pres-\\nbyopia, for the patient Avas but thirty-two years of age. This", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0149.jp2"}, "150": {"fulltext": "132 THE REFRACTION OF THE EYE\\nleads me to deal in a brief manner with the rule of procedure\\nin such cases.\\nIf the myopia is of 8 D. or less, as a rule, the patient will\\nneed but one pair of glasses, which can be used both for the dis-\\ntance and the near point. If the patient has worn glasses from\\nearly childhood, this one pair is usually sufficient for, having\\nworn the glasses steadily, and thereby kept the eye corrected^\\nboth for far and near work, the ciliary muscle has been devel-\\noped. On the other hand, in patients who have not come to\\nthe use of glasses till later in life (fifteen to twenty years of age),\\nor have worn only partial correction, say of myopia of 12 D.\\nonly 8 D. for the distance, and no correction for the near pointy\\nsuch patients will not tolerate the distance glass for constant\\nwear. This is because the ciliary muscle has not been devel-\\noped, the work having been taken from it by the patient tak-\\ning off his glasses and bringing his work close to him at the\\nfocus, punctum remotum^ of his myopic eye. In this way no ac-\\ncommodative effort is necessary the ciliary muscle remains pas-\\nsive, and does not develop. In such cases, the reading glasses\\nhave to be made weaker, just as in the higher grades of myopia.\\nIn high degrees of myopia, 8 D. or over, my rule of\\nprocedure is to find the glasses which give the best distant\\nvision, as in other cases. If the glasses accepted are not\\nhigher than 10 or 12 D., and there are no pathological changes\\nin the fundus of the eye of a serious nature, especially if the\\npatient has been wearing nearly his full correction before, I\\nprescribe these glasses for distant vision. In myopia of higher\\ndegree than this, the patient will not accept his full correction\\neven for the distance, except for very brief periods at a time.\\nIn such cases, the full correction may be prescribed to be used\\nin a lorgnette, while the glasses that are to be worn constantly\\nfor the distance must be made weaker. The amount of the\\nreduction depends on the strength of the glasses the patient\\nhas previously worn, the age of the patient, and the condition", "height": "4261", "width": "2840", "jp2-path": "refractionofeye00davi_0150.jp2"}, "151": {"fulltext": "READING GLASSES m HIGH DEGREES OF MYOPIA 133\\nof the fundus of the eye. Roughly speaking, we would say\\nthat a myopia of 14 D. should wear about 12 D. as a constant\\ndistance glass a myope of 16 D. a 14 D. a myope of 18 D. a\\n15 D. and a myope of 20 D. a 16 D. glass, and so on. There\\nare numerous exceptions to this. It is rare to encounter\\nmyopia of over 25 D., though cases of as high as 40 D. have\\nbeen reported at the New York Ophthalmological Society,^\\nand without conical cornea.\\nTo get the correct reading glasses in these high degrees of\\nmyopia, after having found the glasses I want him to wear con-\\nstantly for the distance, I divide the number of inches at which\\nthe patient wishes to read, or sew, or work, into 40, in order\\nto reduce it to diopters, then subtract the quotient from the dis-\\ntance glasses. 2 The result is the number of the glass that the\\npatient will usually accept for his close work but a reduction\\nmay have to be made in their strength if the patient has not\\nworn glasses for a long time. To give an example, in the last\\ncase reported, the patient accepted 14 D. right and 11 D.\\nleft eye. He wanted a glass to read with comfortably at about\\n1 Webster.\\n2 Eorty is the number of English inches it takes to make a meter, and as\\nmy trial lenses are ground after the English inch (also numbered in diopters), I\\nreckon in that system. Whereas, had my trial lenses been numbered after the\\nFrench system, I would have used 36, the number of French inches it takes to\\nmake a meter.\\nAll trial cases were formerly marked in the inch system. For example, a\\nglass of 10-inch focus would be marked one of 40-inch focus, etc. But\\nas confusion was caused by the difference in length of the English and French\\ninches, the dioptric or metric system of numbering was introduced.\\nIn the dioptric system of numbering, the meter is taken as the unit of\\nmeasure. For example, a glass that will focus parallel rays of light at a distance\\nof one meter is marked one diopter (1 D. thus) a glass that f ocusses the same\\nrays at half a meter would have to be twice as strong, and is marked 2 D.\\nA glass that f ocusses rays at two meters distance would be marked .50 D.,\\nor half a diopter. The numbering goes on in an inverse ratio, for the shorter\\nthe focus the stronger the glass, necessarily. The metric or dioptric system of\\nnumbering is much better than the inch system, for a meter is a meter the world\\nover, while inches of different peoples vary in length from each other.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0151.jp2"}, "152": {"fulltext": "134 THE REFRACTION OF THE EYE\\ni of a meter, or 13 inches. Forty divided by 13 gave 3 D. in\\nround numbers, which, subtracted from the distance glasses,\\ngave 11 D. right and 8 D. left, for his reading glasses,\\nwhich were prescribed.\\nAgain, say in the above case, the patient wished to read at\\n10 inches. Divide 40 by 10, which will give 4 D. subtract\\nthis from the distance glasses, and we have 10 D. right and\\n7 D. left, for near work. Or, say the patient wanted to play\\nthe piano, or use his eyes for other occupation that would re-\\nquire good vision at a distance of 20 inches divide 40 by 20,\\nsubtract 2D., the quotient, from the distance glasses, and we\\nwould have, in the above case, 12 D. right and 9 D. left,\\nfor the near work and so on.\\nIt should be borne in mind here, as, indeed, it should be at\\nall times in fitting glasses, that all eyes are not alike in their\\nworking capacity, and will not conform, in exactly the same\\nway, to any set standard or rule. This does not mean that we\\nshould not have a rule at all, but that we should have enough\\nintelligence to vary the rule to suit the case^ and not try to make\\nevery case fit some cast-iron rule.\\nIn some cases, for the near point, we have to subtract more\\nfrom the distance glasses than we have indicated here, and in\\nsome cases less. The power of convergence has something to do\\nwith it the strength of glasses that the patient has previously\\nworn, the age of the patient, also, all have to be taken into\\nconsideration when giving reading glasses to a myope. Indeed,\\nLandolt has laid it down as a general rule, in all degrees of\\nmyopia, that a myope must be prohibited from wearing a con-\\ncave glass for any distance at which he can see clearly without\\naccommodation. 2 For example, a myope of 2 D. should not\\n1 In order to get inches into diopters, divide them into 40 if using the Eng-\\nlish inch, or into 36 if using the French inch, and vice versa. For example\\n(English inch), a 10-inch glass is equal to 4 D., and a 4 D, 10-inch glass a\\n20-inch glass 2 D., and a 2 D. glass 20 inches, etc.\\n2 Landolt, The Befraction and Accommodation of the Eye, p. 490.", "height": "4258", "width": "2698", "jp2-path": "refractionofeye00davi_0152.jp2"}, "153": {"fulltext": "READING GLASSES IN HIGH DEGREES OF MYOPIA 135\\nhave any glass at all for distances under 20 inches, because his\\npunctum remotum is at 20 inches, and he can see clearly without\\nthem up to that point. I believe it is a good plan myself, how-\\never, in all cases of myopia under 8 D., who are compelled to\\nwear glasses for the distance, to keep the glasses on all the\\ntime, unless troublesome asthenopia results then the distance\\nglasses should be weakened according to the rule laid down\\nabove; or, if only of moderate strength, 3 or 4 D., taken off\\naltogether for reading unless there is astigmatism present, when\\nonly the cylindrical part of the glass should be left on for read-\\ning and close work. The reason that I prefer to leave the dis-\\ntance glasses on for near work in such cases is first, to exercise\\nand develop the ciliary muscle second, to render the eye em-\\nmetropic for all distances, and thus keep up the proper relation\\nbetween accommodation and convergence third, because it is\\nless trouble to keep the glasses on all the time than to be taking\\nthem off and putting them on frequently. Of course, in very\\nhigh degrees of myopia, two pairs of glasses have to be resorted\\nto, and sometimes three, if we include the lorgnette which they\\nsometimes use for only a few moments. In cases of high degree\\nof myopia, it is not always, in fact, it is never, simply a ques-\\ntion of glasses, especially where progressive or malignant myopia\\nis to be dealt with. In such cases, a general hygienic regime\\nhas to be followed, so far as the eyes are concerned, and the\\nconstitution built up with tonics. All close work with the ej es\\nmust be prohibited, shaded glasses worn, local blood-letting\\npracticed, the patient made to exercise and take the proper\\namount of rest, and so forth. In fact, the general condition of\\nthe patient should be brought up to the best. Unfortunately,\\nsuch cases often occur in childhood, when the patient is try-\\ning to pursue his studies. It is unnecessary to say that such\\npatients must be taken out of school, because close application\\nto books always makes the mj^opia Avorse.\\nIn cases of high degrees of myopia, not malignant in char-", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0153.jp2"}, "154": {"fulltext": "136 THE REFRACTION OF THE EYE\\nacter, that is, with healthy fundi, or, at most, with only a\\nslight posterior staphyloma, and with but little tendency to\\nincrease, it is well for the patients to use the eyes as little as\\npossible, and only with good light. In order to prevent strain-\\ning the eyes, these patients often acquire the practice of using\\nbut one eye at a time, especially for near work, pulling off the\\nglasses and bringing the print up to the focus (^pmictum remo-\\nturn) of the eye he uses. In this way he uses no accommoda-\\ntion, and, at the same time, the images are much larger for the\\neye without the strong myopic glasses, which always make\\nobjects look much smaller. The eye that is not used usually\\nswings out, that is, diverges. Where the eyes are sound, how-\\never, I always encourage the use of glasses, and, in that way,\\ngive the stimulus to binocular vision both for the distance and\\nfor the near point. A divergent squint is sometimes prevented\\nin this way, just in the same way as a convergent squint is\\nsometimes prevented, and even cured in young children after\\nonce having appeared, by wearing plus glasses.\\nThe following case of moderate degree of myopia in\\none eye, and only a small amount in the other, with a ten-\\ndency to, and, at times actual, squint outward, is a case in\\npoint.\\nCase LIV. Myopia of moderate amount in one eye and\\nsmall amount in the other Occasional divergent squint; Astheno-\\npia Relief of the squint and asthenopia with correcting glasses.\\nJanuary 4, 1898, Miss E. M. L., aged twenty-one years, in\\ngood health, has been near-sighted in the right eye since a\\nchild, her family have noticed at times, when she was looking\\nin the distance, that the right eye would turn outward. With\\nclose attention, however, the eye would turn back, and not\\nsquint. When she reads at night, the eyes tire, but there is\\nlittle pain in them, and she rarely has headaches.\\nThe ophthalmometer showed a small amount of corneal\\nastigmatism iu each eye; and, on the first test, the patient", "height": "4249", "width": "2789", "jp2-path": "refractionofeye00davi_0154.jp2"}, "155": {"fulltext": "ILLUSTRATIVE CASES 137\\naccepted compound glasses, but, on the second test, simple\\nmyopic spherical glasses gave the best vision.\\nOphthalmometer. Astigmatism with the rule, .75 D., axis\\n75\u00c2\u00b0+ or 165\u00c2\u00b0- right eye .25 D., 90\u00c2\u00b0+ or 180\u00c2\u00b0- left eye.\\nTest cards and trial lenses,\\nR. Y. 2 A U-^ 4.50 D.-.50 D. cyl., 165\u00c2\u00b0.\\nL. V 1^ W.- .25 D.-.25 D. cyl., 180\u00c2\u00b0.\\nReads Jaeger No. 1, 3 to 12 inches right eye, and from 5 to\\n25 inches in the left eye. Unless she looks at the point atten-\\ntively, the right eye turns outward for the near point also,\\nwhen looking in the distance, unless she is attentive, the right\\neye swings outward.\\nOphthalmoscope. Myopia 5 D. right eye; myopia 1 D.(?)\\nleft eye normal fundi.\\nOn account of a mild conjunctivitis, alum was applied to\\nthe lids, an astringent wash prescribed, and the patient directed\\nto come again in a week for a second test. This seemed advis-\\nable, because there were unmistakable signs of spasm of accom-\\nmodation during the subjective test. The retinoscopic test\\nwas unsatisfactory.\\nSecond test the ophthalmometer gave the same reading\\nas at the first test.\\nR-V. A\\\\:ff W.-5 D.\\nL-V. 1^ :|f W.- .50 D.\\nThe ophthalmoscope and retinoscope both confirmed the\\nsubjective test. The tendency to spasm of accommodation had\\nsubsided. I ordered for constant wear \u00e2\u0080\u00941.50 D. rio-ht and a\\nplain glass left. The patient has been under observation for\\na period of eight months. She has single binocular vision both\\nfor near and far with the glasses, is entirely free from astheno-\\npia, and is much pleased with the result.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0155.jp2"}, "156": {"fulltext": "138 THE REFRACTION OF THE EYE\\nCase LV. Myopic astigmatism of moderate amount; Pres-\\nbyopia; Simple minus cylindrical glasses for the distance, and\\ncross-cylindrical glasses for reading. May 28, 1897, L. J., aged\\nforty-five years, iu good health, has worn glasses since nineteen\\nyears of -age, which are all right for the street now, but have\\nnot been comfortable for reading purposes for the last two\\nor three years. Her distance glasses are 2. D. cyl., 180\u00c2\u00b0, in\\neach eye.\\nOphthalmometer. Astigmatism with the rule, 2.50 D., axis\\n90\u00c2\u00b0 180\u00c2\u00b0- in each eye.\\nTest cards and trial lenses.\\nR. V. f^ 1^ W. -2D. cyl., 180\u00c2\u00b0.\\nL. V. ||-:|^W.-2D. cyl.,180\u00c2\u00b0.\\nReads Jaeger No. 1 from 7 to 18 inches, with 1 D.\\nspherical glass added to the distance glasses.\\nOphthalmoscope. M. 2D. in the vertical meridian, and\\nemmetropia in the horizontal meridian in each eye.\\nThe patient was allowed to continue the minus cylindrical\\nglasses for distant vision, and ID. 2D. cyl., 180\u00c2\u00b0, was\\nordered for each eye for reading purposes. This glass in\\neffect is the same as cross-cylinders, that is, -h ID. cyl.,\\n90\u00c2\u00b0 1 D. cyl., 180\u00c2\u00b0. But, before going into details of the\\ntransposition of glasses that is made necessary in cases of\\nmyopes who have become presbyopic, I wish to report two\\nother cases of simple myopic astigmatism in presbyopes, in\\norder to have two or three cases for illustration, rather than\\none.\\nCase LVI. Simple myopic astigmatism with the rule; Pres-\\nbyopia; 3Iinus cylindrical glasses for the distance, and plus cylin-\\ndrical glasses for the near work. August 16, 1896, Samuel T.,\\naged forty-six, in good health, has worn glasses since twenty\\nyears of age, on account of near-sightedness. For the past", "height": "4243", "width": "2793", "jp2-path": "refractionofeye00davi_0156.jp2"}, "157": {"fulltext": "ILLUSTRATIVE CASES 139\\ntwo years he has experienced some trouble in his near work,\\nespecially when reading at night.\\nOphthalmometer. Astigmatism with the rule, 1.50 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 in each eye.\\nTest cards and trial\\nV- 1^ ft W. 1 D. cyl., 180\u00c2\u00b0.\\nL- V. =1^ fl W. 1 D. cyl., 180\u00c2\u00b0.\\nReads Jaeger No. 1 from 8 to 20 inches, with +1 D. sphere\\nadded to the cylindrical glasses.\\nOphthalmoscope. M. 1 D. in the vertical meridian (90\u00c2\u00b0),\\nand emmetropia in the horizontal meridian (180\u00c2\u00b0) in each eye.\\nThe patient is now wearing\u00e2\u0080\u0094 ID. cyl., 180\u00c2\u00b0, exactly the\\nsame glasses he accepted in this test, and they were ordered\\ncontinued. For reading glasses -fl D. cyl., 90\u00c2\u00b0, was ordered\\nfor each eye.\\nCase LVII. Simple myopic astigmatism ivith the rule in one\\neye and against the rule in the other Presbyopia Minus cylin-\\ndrical glasses for the distance and plus cylindrical glasses for\\nreading. October 10, 1896, Kate M., aged forty-one, in good\\ngeneral health, for the last year her eyes have given her a\\ngreat deal of trouble for close work. The vision blurs, and the\\neyes and head ache after using the eyes.\\nOphthalmometer. Astigmatism with the rule, 1 D., axis\\n60\u00c2\u00b0 or 150\u00c2\u00b0 right eye astigmatism against the rule, 1 D.,\\n135\u00c2\u00b0+ or 45\u00c2\u00b0- left eye.\\nTest cards and trial lenses.\\nR. V. li W. .50 D. cyl., 15\u00c2\u00b0.\\nL. V. 1^ li W. .50 D. cyl., 45\u00c2\u00b0.\\nReads Jaeger No. 1 at 8 inches, with +.50 D. added to the\\ndistance glasses.\\nOphthalmoscope.\u00e2\u0080\u0094 M. 1 D. at 60\u00c2\u00b0 and Em. at 150\u00c2\u00b0 right\\neye; M. 1 D. at 135\u00c2\u00b0 and Em. at 45\u00c2\u00b0 left eye.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0157.jp2"}, "158": {"fulltext": "140\\nTHE REFRACTION OF THE EYE\\nOn a second test, this patient accepted the same glasses,\\nboth the distance and the near, as at the first test. As her\\neyes gave her no special trouble for the distant vision, I pre-\\nscribed only the reading glasses, +.50 D. cyl., 60\u00c2\u00b0 right, and\\n4-.0OD. cyl., 135\u00c2\u00b0left.\\n150,\\n135\\nR. E.\\nL. E.\\nFig. 64.\\nIt will be noticed in this case that although the instrument\\nreads astigmatism against the rule, 1 D., in the left eye, the\\npatient accepts only .50 D. cyl., the same amount as the other\\neye, wherein the instrument reads astigmatism with the rule,\\n1 D. This makes me repeat what I have alread}^ pointed out\\nabove, that when the chief meridians are exactly at 45\u00c2\u00b0 and\\n135\u00c2\u00b0, as in the left eye in this case, the terms with the rule\\nand against the rule do not strictly hold. This should be\\nborne in mind, therefore.\\nPresbyopic Glasses for Myopes\\nFor the benefit of students and beginners in the practice of\\nophthalmology, I think it well at this place to consider briefly\\nthe influence of presbyopia as it affects the reading glasses.", "height": "4259", "width": "2815", "jp2-path": "refractionofeye00davi_0158.jp2"}, "159": {"fulltext": "PRESBYOPIC GLASSES FOR MYOPES 141\\nespecially in myopes. It is, as a rule, an easy matter to give\\nthe correct reading glasses to an emmetropic, or a hyper-\\nmetropic individual. To do so it is necessary only to add\\na certain increase to the distance glass (if the patient accepts\\nany distance glass), usually about 1 D. spherical glass for\\neach five years of age after forty years of age, to get the cor-\\nrect glasses. A better standard, perhaps, is the one of giving\\nthe glasses that the patient can read with, with comfort, at\\n13 inches, or with effort at 8 inches. As stated above, this\\nrequires about 1 D. for each five years after forty years\\nof age but some patients will accept but .50 D., while others\\nwill require as much as 1.50 D., or even more in exceptional\\ncases, for each five years after forty years of age, in order to\\nread with comfort (Jaeger No. 1) at 13 inches, or with effort\\nat 8 inches. For instance, to give an example or two, an\\nemmetrope at forty-five years of age should wear about 1 T\\nfor reading, and at fifty years of age 2 D., and at fifty-five\\nyears 3 D., and so on. The variation from this is easily\\nascertained by having the patient read the Jaeger No. 1 type\\nat 8 inches. The glass that is required to enable him to\\nread this type at that distance, with effort, is the correct\\n^lass (Bonders).\\nAgain, a hypermetrope who is wearing -1- 2 D. for the dis-\\ntance should wear about 3 D. for reading when forty-five\\nyears of age, and 4 D. at fifty years, etc. Or if the patient\\nis wearing compound hypermetropic glasses for the distance,\\nit is only necessary to add to the spherical part of the glass the\\nusual amount of -f 1 D. for each five years, in order to get the\\ncorrect reading glasses, leaving the cylindrical part as it is.\\nIn myopic astigmatism the fitting of presbyopic glasses is\\nnot so easy, especially for the beginner for the changing from\\nminus cylindrical glasses to plus, with change of axis, though\\napparently very simple by the algebraic equation, is not, as a\\nrule, quickly grasped by the student. For this reason I not", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0159.jp2"}, "160": {"fulltext": "142 THE REFRACTION OF THE EYE\\nonly teach them the method by algebraic equation, but draw-\\ndiagrams of the eye shoAving the focus of the two chief\\nmeridians for the distance, and then the change of focus\\nbrought about by presbyopia, calculating on the basis of\\n1 D.i for each five years. This places before the eye of\\nthe student the change of focus of each meridian, and at the\\nsame time indicates the nature and strength of the glass neces-\\nsary for the near w^ork of the patient. It has the further\\nadvantage of making the student think of the eye under obser-\\nvation, and does not let him decide the matter by an abstract\\nalgebraic equation. This may seem of little importance to those\\nwho do not instruct but, I am sure, to teachers, this concrete\\nway (wdth the assistance of diagrams) of imparting knowledge\\nwill at once be apparent as the better method of teaching.\\nNow, in simple myopia without astigmatism, the fitting of\\npresbyopic glasses is not difficult, because, adding 1 D.\\n(algebraically) for each five years of age after forty to the\\ndistance glass, we easily get the right glass for reading or\\nw^orking purposes. To take an example, say the patient wears\\n2D. for distant vision, and is forty-five years of age. Add\\n-1- 1 D. to 2 D., and we have left \u00e2\u0080\u0094ID., which would be\\nthe reading glass. At fifty years of age the patient would\\nbe 2 D. presbyopic. Plus 2 D. added to \u00e2\u0080\u00942D. equals 0, that\\nis, they exactly neutralize, so that the patient would need na\\nreading glass at this age. At fifty-five years of age, 3 D.\\nadded to \u00e2\u0080\u00942D. would give 1 D., which would be the cor-\\nrect glass.\\nIn cases of simple myopia of high degree, wdiere tw^o pairs\\nof glasses are worn, in giving presbj-opic glasses, w-e add the\\npresbyopic glass to his weaker glasses (the glasses that he uses\\nfor near work), and leave the distance glass as it is. Neverthe-\\nless, even this distance glass of high myopes has to be w^eak-\\nened as the patie^it advances in age for even the static\\n1 Of course the 8-inch test for Jaesrer No. 1 is the final decisive test.", "height": "4250", "width": "2841", "jp2-path": "refractionofeye00davi_0160.jp2"}, "161": {"fulltext": "TRANSPOSITION OF GLASSES 143\\nrefraction of the eye begins to get weaker at fifty years of\\nage, and at eighty years of age has actually decreased about\\n2.50 D. In Case LIU, for instance, where 14 D. right and\\n11 D. left were ordered for the distance glass, and \u00e2\u0080\u009411 D.\\nright and 8 D. left for reading, when this patient reaches\\nforty-five years of age he should wear, on account of his 1 D.\\nof presbyopia, 1 D. added to 11 D. right, and 1 D.\\nadded to 8 D. left, which would give for reading glasses\\n10 D. right and 7 D. left. At fifty years of age, -f 2 D.\\nadded to 11 D. and 8 D. would give 9 D and 6 D.,\\nrespectively, as the reading glass, and so on.\\nOn account of the decrease of the static refraction of the\\neye, his strong distance glasses, 14 D. right and 11 D.\\nleft, should be decreased in strength, and much more than is\\nindicated by the tables of scales as given in the various text-\\nbooks. At the age of sixty, for instance, the static refraction\\nhas decreased .50 D., yet a much greater reduction in the\\nstrength of the distance glasses has to be made than this\\namount where the myopia is of high degree.\\nIn myopic astigmatism in presbyopes we have to deal with\\nthe transposition of cylindrical glasses, and it is not so easy as\\nin cases of simple myopia and spherical glasses.\\nI will take some of the cases reported in this chapter as\\nillustrative examples. In Case LVI, the patient accepted for\\nthe distance ID. cylindrical glass, axis 180\u00c2\u00b0, in each eye.\\nHe was forty-six years of age, and required a reading glass.\\nHe accepted 1 D. cyl., 90\u00c2\u00b0, in each. A 1 D. spherical\\nglass added to 1 D. cyl., 180\u00c2\u00b0, would be in effect 1 D.\\ncyl., 90\u00c2\u00b0. As the latter glass was simpler, lighter, and cheaper,\\nit was prescribed. A glance at Fig. QS will show the change\\nin focus brought about by the 1 D. of presbyopia.\\nThe 1 D. of myopia in the vertical meridian is just neutral-\\nized by the 1 D. of presbyopia Avhile the horizontal meridian,\\nwhich was emmetropic, becomes in effect hypermetropic 1 D.,", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0161.jp2"}, "162": {"fulltext": "144\\nTHE EEFRACTIOI^ OF THE EYE\\nby reason of the 1 D. of presbyopia. In other words, the eye\\nfor reading purposes at that age is converted into a simple\\nhypermetropic, astigmatic eye, and requires a simple 1 D.\\ncyl., 90\u00c2\u00b0, to correct same.\\nAt fifty years of age the patient would require for a read-\\ning glass 1 D.s 1 D. cyl., 90\u00c2\u00b0 for, on account of 2 D.\\nof presb3^opia, the focus in the vertical meridian, for reading\\npurposes, has receded behind the retina, as well as the focus in\\nthe horizontal meridian (in the vertical meridian 1 D. and in\\n90\u00c2\u00b0\\nDISTANCE\\nNEAR\\n180\\nFiQ. 65. Showing focuses of chief meridians for distant vision and for near vision at\\nthe age of forty-five years, iu simple myopic astigmatism of 1 D.\\nthe horizontal meridian 2D.). A 1 D. sphere corrects the\\nvertical meridian and half the presbyopia of the horizontal\\nmeridian, the 1 D. cyl., 90\u00c2\u00b0, being required to complete the\\ncorrection in the horizontal meridian.\\nAt fifty-five years of age, this patient would require 4- 2\\nD.s -hi D. cyl., 90\u00c2\u00b0, and so on, about -f 1 D. spherical glass\\nextra for each five years being required to be added to the\\ncylindrical glass.\\nTake another example, suppose the patient accepts 2D.\\ncyl., axis 180\u00c2\u00b0, for the distance, as in Case LV. At forty-five", "height": "4257", "width": "2826", "jp2-path": "refractionofeye00davi_0162.jp2"}, "163": {"fulltext": "ILLUSTRATIVE CASES\\n145\\nyears of age, this patient would be about 1 D. presbyopic, and\\nshould wear for reading 1 D.\u00e2\u0080\u0094 2 D. cyl., 180\u00c2\u00b0, in each eye\\nor, if we chose, we could give cross-cylinders, e.g.^ +1 D. cyl.,\\n90\u00c2\u00b0\u00e2\u0080\u0094 1 D. cyl., 180\u00c2\u00b0, which glass is exactly the same in effect\\nas the sphero-cylindrical glass 1 D. 2 D. cyl., 180\u00c2\u00b0.\\nTo make this perfectly plain, we will give a diagram of the\\neye, showing, first, the foci of the two chief meridians for dis-\\ntant vision and, second, the foci as affected by the 1 D. of\\npresbyopia at forty-five years of age.\\nDISTANCE\\nNEAR\\n180\\n180\\nFig. 66. Showing focuses of the chief meridians in simple myopic astigmatism of\\n2 D. for distant vision and for near vision at the age of forty-five years.\\nThe 1 D. of presbyopia neutralizes 1 D. of the myopic\\nastigmatism in the vertical meridian (leaving ID. of it uncor-\\nrected), and at the same time renders the horizontal meridian\\n(which is emmetropic) presbyopic, or in effect hypermetropic\\n1 D. Thus the eye for reading purposes is mixed astigmatic,\\nsince it focusses rays of light in front of the retina in the verti-\\ncal meridian, and back of the retina in the horizontal meridian.\\nNow, to correct this we can give either the cross-cylindrical\\nglasses, 1 D. cyl., 90\u00c2\u00b0 -ID. cyl., 180\u00c2\u00b0; or we can give\\nsphero-cylindrical glasses, 1 D. 2 D. cyl., 180\u00c2\u00b0. In the", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0163.jp2"}, "164": {"fulltext": "146 THE REFRACTIOX OF THE EYE\\nfirst instance, with the cross-cylinders, the 1 D. cyl., 90\u00c2\u00b0,\\ncorrects the 1 D. of presbyopia in the horizontal meridian, and\\nthe \u00e2\u0080\u0094ID. cyl., 180\u00c2\u00b0, corrects the one remaining diopter of\\nmj^opic astigmatism in the vertical meridian. In the second\\ninstance, with the sphero-cylindrical glasses, the 1 D. sphere\\ncorrects the 1 D. of presbyopia in the horizontal meridian, and\\nat the same time renders the eye myopic to that extent in the\\nvertical meridian and the increase of myopic astigmatism by\\n1 D. in addition to the 1 D. already present makes it necessary\\nto give \u00e2\u0080\u00942D. cyl., 180\u00c2\u00b0, instead of 1 D. cyl., as when\\ncross-cylinders were prescribed. In other words, we have to\\nneutralize the effect of the plus spherical glass in the vertical\\nmeridian. This, of course, makes a heavier glass than a cross-\\ncylindrical. The field of vision also is made somewhat smaller\\nby the sphero-cylindrical glasses than by the cross-cylindrical.\\nBut both of these objections are of but little importance in\\nmixed astigmatism of low degree, as in the present instance.\\nWhen the mixed astigmatism is of large amount, cross-cylin-\\ndrical glasses are to be given in preference to sphero-cylindri-\\ncal, as a general rule.\\nAt fifty years of age, this patient (Case LV) would\\nrequire a simple 2 cyl. axis 90\u00c2\u00b0, because at this age the\\n2 D. of myopic astigmatism in the vertical meridian is just\\nneutralized by the 2 D. of presbyopia, while the emmetro23ic\\nhorizontal meridian is rendered 2 D. presbyopic (or hyperme-\\ntropic in effect), and requires the -f- 2 D. cyl., 90\u00c2\u00b0, to correct\\nsame. At fifty-five years of age, the patient would wear\\n-f- 1 D. 4- 2 D. cyl., 90\u00c2\u00b0 and at sixty years, -f- 2 D. -f- 2 D.\\ncyl., 90\u00c2\u00b0, and so on.\\nFor the transposition of glasses, made necessary on account\\nof presbyopia, in compound myopic astigmatism, and in mixed\\nastigmatism, suitable examples are given for illustration in the\\nchapters on compound myopic astigmatism and mixed astig-\\nmatism, which immediately follow.", "height": "4257", "width": "2834", "jp2-path": "refractionofeye00davi_0164.jp2"}, "165": {"fulltext": "CHAPTER YI\\nCOMPOUND MYOPIC ASTIGMATISM ANTIMETROPIA ILLUSTRA-\\nTIVE CASES ACCESSORY EFFECTS OF STRONG MYOPIC\\nGLASSES\\nIn testing for glasses in compound myopic astigmatism, we\\nbegin tlie test in exactly the same way as when testing for\\nthe glasses in simple myopic astigmatism. That is, we examine\\nthe eye first with the ophthalmometer to ascertain if there is\\nany corneal astigmatism. Having found the amount and axis\\nof the astigmatism, we next begin the subjective test with the\\ntrial case and test card. And here, and as a matter of fact in\\nall errors of refraction where astigmatism is present, we begin\\nthe test with weak plus cylindrical glasses, unless we know\\nbeforehand the nature of the error of refraction for the ex-\\namination with the ophthalmometer does not reveal the nature\\nof the error of refraction, and plus glasses are begun with in\\norder to avoid inciting a spasm of accommodation. If the\\npatient proves not to be hypermetropic, no harm is done and\\nbut little time lost. We then begin with weak minus cylin-\\ndrical glasses at the axis indicated by the ophthalmometer, and\\ngradually increase their strength so long as they improve\\nvision, being careful to stop with the weakest glass that gives\\nthe best vision. If the vision is not brought up to perfect,\\nwith cylindrical glasses alone, we next add a weak minus\\nspherical glass to the cylinder, and if it improves vision,\\ngradually increase it in strength until the vision ceases to be\\nimproved. The weakest minus glasses that give the best\\nvision are given.\\n1 As explained in a previous chapter, if minus glasses are begun with they\\nare often accepted, though the patient be hypermetropic.\\n147", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0165.jp2"}, "166": {"fulltext": "148 THE REFRACTION OF THE EYE\\nIn very high degrees of myopia complicated with astig-\\nmatism, especially where the astigmatism is of small or only\\nmoderate amount, we have to correct part or most of the\\nmyopia before the cylindrical glass is appreciated when placed\\nin front of the eye. Starting the test in the routine way in\\nsuch cases, plus glasses would of course make the vision worse,\\nand would be refused and minus cylindrical glasses, though\\naccepted, would not appreciably improve vision. Notwith-\\nstanding the fact that the cylindrical glasses, as indicated\\nby the ophthalmometer, do not appreciably affect the vision\\none way or the other, I leave them in the trial frames and add\\nminus spherical glasses to them, rapidly increasing them in\\nstrength. If the poor vision is due to myopia, and no very\\nserious fundus changes have taken place to cause amblyopia,\\nthe minus spherical glasses, which give the best vision, are\\nsoon found. When I have reached this point in the test, I\\nthen leave the minus spherical glasses in the trial frames and\\ngo back to the cylindrical glasses, increasing and diminishing\\nthem in strength alternately, to see if vision can be further\\nimproved for, with the myopia corrected, any change in the\\ncylindrical glasses is more easily perceived. However, as\\nabove stated, where the myopia is large in amount, 8 D. or\\nmore, and the astigmatism small in amount, cylindrical glasses\\nincrease the vision very little when added to the spherical\\nglasses, at times even when the astigmatism is as much as 2 D.\\nIn such cases, and particularly when the astigmatism is with\\nthe rule and exactly at 180\u00c2\u00b0, it is often best to give simple\\nspherical glasses alone, tilting them slightly on the horizontal\\naxis, the upper part forward, to get the necessar}^ cylindrical\\neffect. The patient will do this tilting for himself, if it is not\\ndone for him, after wearing them for a few weeks.\\nThe giving of a simple spherical glass and tilting it on the\\nhorizontal axis is, when it can be done, advantageous in three\\nways first, it is a simple glass, and not a compound one", "height": "4261", "width": "2807", "jp2-path": "refractionofeye00davi_0166.jp2"}, "167": {"fulltext": "ILLUSTRATIVE CASES 149\\nsecond, it is a lighter glass and third, it is a cheaper glass\\nthan a compound one.\\nWe are to be guided in such instances (giving only spher-\\nical glasses where there is a large amount of myopia and\\nonly a small amount of astigmatism) by the increase of vision\\nthe cylindrical glass gives when added to the spherical glass.\\nFor example, say a patient accepts a 10 D. spherical glass\\nand his vision is brought up to J^ with it and by adding a\\n.75 D. cyl., axis 180\u00c2\u00b0, the vision is increased to only -|-g\\nor not one whole line. In such case I would not give the\\ncompound glasses, but the simple 10 D., and tilt them\\nslightly forward on the horizontal axis.\\nWhere the myopia is not large in amount (under 8 D.), and\\nthe astigmatism is moderate or small in amount, and when the\\nvision is considerably improved by the correction of this astig-\\nmatism, it is best to give a compound glass. This is the more\\nimportant if the axis of the astigmatism is off from 180\u00c2\u00b0, for\\nthen it is difficult to get the proper cylindrical effect by tilting\\nthe spherical glasses.\\nWhere there are fundus complications, vision will not, as a\\nrule, be improved much with any glass whatsoever. Moreover,\\nif the myopia is of the progressive type, glasses are of second-\\nary importance for, in such cases, constitutional treatment\\nand general hygienic conditions are much more to be consid-\\nered. The eyes should be given complete rest, and, if sensi-\\ntive to light, shaded glasses should be worn. In cases of\\nchildren with progressive myopia, they should be taken from\\nschool, or be allowed to go for only one or two hours a day\\nfor, if close application at books is persisted in, the eyes are\\nirreparably injured by hastening the progress of the disease.\\nCase LVIII. A typical case of compound mi/opic asficpna-\\ntism Slight asthenopia; Vision brought up to perfects with\\nglasses. April 4, 1897, C. A. B., aged twenty-seven years,\\nconsulted me four months ago on account of a chalazion on the", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0167.jp2"}, "168": {"fulltext": "150\\nTHE REFRACTION OF THE EYE\\nright upper eyelid, which was cured by incising and curetting.\\nHe comes now on account of poor vision, and for slight pain\\nin the eyes, after using them for continuous close work. His\\nvision has never been very good, and, until lately, he has been\\nfree from asthenopia.\\nOphthalmometer. Astigmatism with the rule, 2.50 D.,\\naxis 90\u00c2\u00b0+ or 180\u00c2\u00b0\u00e2\u0080\u0094 in each eye.\\nTest cards and trial lenses. The vertical lines on the\\nclock-dial are seen plainest, though none of them are seen\\nvery plain.\\ntA U 3-50 D- 2.50 D. cyl., 180\u00c2\u00b0.\\nL- 2W II +W.- 3.50 D.- 2.50 D. cyl., 180\u00c2\u00b0.\\nReads Jaeger Ko. 1 from 4 to 20 inches.\\nOphthalmoscope. M. 5 D. in the vertical meridian (90\u00c2\u00b0),\\nand M. 3 D. in the horizontal meridian (180\u00c2\u00b0), in each eye.\\nThe fundus in each eye is normal.\\nFig. (J7.\\nFive days later a second test was made. The ophthalmo-\\nscope and ophthalmometer showed the same condition as at the\\nfirst test.", "height": "4248", "width": "2789", "jp2-path": "refractionofeye00davi_0168.jp2"}, "169": {"fulltext": "ILLUSTRATIVE CASES 151\\nTest cards and trial lenses.\\niA 1^ 4- W. 3 D. 2.25 D. cyL, 180\u00c2\u00b0.\\nL. V. 2V^ 1^ W. -3D.- 2.25 D. cyL, 180\u00c2\u00b0.\\nThis last glass was ordered. It has given relief from his\\nasthenopia, and is worn with great satisfaction and comfort.\\nI may say that my routine method was followed in testing this\\ncase. Plus cylindrical glasses were first tried these were\\nrejected. Then minus cylindrical glasses were tried, and the\\npatient accepted a 2.25 D. cyl., 180\u00c2\u00b0, with improvement in\\nvision but, as it was not brought up to normal vision, minus\\nspherical glasses were added to the cylindrical, the strength\\nbeing gradually increased till 3D. was reached. As this\\ncombination of glasses was the weakest minus glass that gave\\nhim the best vision, it was ordered.\\nThe same routine procedure was pursued in all of the fol-\\nlowing cases.\\nCase LIX. Compound myopic astigmatism^ where the myo-\\npia is cofisiderable in amount and the astigmatism small in\\namount Patient is luearing spherical glasses Slight asthenopia^\\nwith poor vision Relief with glasses. February 7, 1895, Annie\\nC, aged twenty-eight years, in good general health, consulted\\nme on account of poor vision and occasional headaches over the\\nbrows. She comes of a myopic family. She fitted herself to\\nglasses sometime ago 5 D. sphere each eye), but they have\\nnot given relief.\\nOphthalmometer. Astigmatism with the rule, 2 D., axis\\n80\u00c2\u00b0+ or 170\u00c2\u00b0- right eye 2 D., axis 100\u00c2\u00b0+ or 10\u00c2\u00b0- left eye.\\nTest cards and trial lenses.\\n2*0 M W.- 5 D.- 1.50 D. cyl., 170\u00c2\u00b0.\\nL- V. 2W U 5 D. 1.50 D. cyl., 10\u00c2\u00b0.\\nHeads eJaeger No. 1, 5 to 15 inches.\\nOphthalmoscope.\u00e2\u0080\u0094 M. 7 D. at 80\u00c2\u00b0 and 5 D. at 170\u00c2\u00b0 right\\neye M. 7 D. at 100\u00c2\u00b0 and 5 D. at 10\u00c2\u00b0 left eye.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0169.jp2"}, "170": {"fulltext": "152\\nTHE REFRACTION OF THE EYE\\nThere is a narrow crescentic staphyloma to the temporal\\nside of the disk in each eye.\\nR. E.\\nFig. 68.\\nL. E.\\nOn a second test the patient accepted the same glasses as at\\nfirst they were ordered, and have given satisfaction for more\\nthan three years.\\nCase LX. Compound myopic astigmatism^ the myopia being\\nlarge in amount^ while the astigmatism is small in amount.\\nJune 15, 1894, Miss E. E. D., in fairly good health only, con-\\nsulted me on account of poor vision. There is no asthenopia.\\nShe comes from a myopic family, and her sight has been poor\\nfrom childhood.\\nOphthalmometer. Astigmatism with the rule, 2.25 D., axis\\n100\u00c2\u00b0+ or 10\u00c2\u00b0- right eye 2.25 D., axis 75\u00c2\u00b0+ or 165\u00c2\u00b0- left eye.\\nTest cards and trial\\nR. V.\\n200 TO\\n2^ ^v, _ 16 D. 1.25 D. cyl., 10\u00c2\u00b0.\\n**200*70\\n16 D. 1.25 D. cyl., 165\u00c2\u00b0.\\nReads Jaeger No. 1 at 7 inches, with 10 D. spherical\\nglass on each eye.", "height": "4238", "width": "2803", "jp2-path": "refractionofeye00davi_0170.jp2"}, "171": {"fulltext": "ILLUSTRATIVE CASES 153\\nOphthalmoscope. Myopia of 16 D. in each eye. There is\\na large posterior staphyloma in each, but there is little cho-\\nroidal change.\\nA second test resulted in the patient accepting the same\\nglass as at first ordered, 16 D. for the distance, in the form\\nof a hand-lorgnette, and 10 D. for close work.\\nIn this case the myopia was so great and the amblyopia so\\nmarked that the cylindrical glass improved vision but little,\\nso it was not added to the spherical glass, especially as the\\nlatter was already very heavy. Moreover, it many times hap-\\npens, in these cases of high degree of myopia, that the patient\\nis not able to wear the full correction, even in the street. In\\nsuch instances we must reduce the power of the glass if we\\ngive it for constant wear or give it full strength in a lorg-\\nnette, to be used for only a few moments at a time, when\\nthe patient wishes to see distinctly.\\nPatients who have worn glasses from childhood can wear\\nmuch nearer their full correction, in these high degrees of\\nmyopia, than those who have worn very weak glasses, or none\\nat all till later in years. The reasons for this are first, in\\nthose who wore glasses that corrected most of their myopia\\nfrom early childhood, the ciliary muscle had to be used when\\nlooking close at hand, and in this way it was developed and\\nstrong glasses can on this account be worn without fatigue.\\nBut in those who have not worn anything like their full cor-\\nrection, or have worn no glass at all, the ciliary muscle remains\\nundeveloped from non-use and when strong glasses are pre-\\nscribed, requiring the use of the ciliary muscle for near work,\\nthe eyes easily tire, because of the very weak ciliary muscle.\\nSecond, the distorting and minifying effects of strong myopic\\nglasses are not noticed so much by a child in early life, and\\nhe grows accustomed to the effects as natural ones while the\\neffects of such glasses prescribed later in life are very annoy-\\ning, so much so, that in some cases patients will not tolerate", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0171.jp2"}, "172": {"fulltext": "154 THE REFRACTIOiSr OF THE EYE\\nanything like the full correction. The prismatic action and\\nminifying action of strong minus glasses have to be taken into\\nconsideration, and a reduction in the strength of the glass has\\nto be made to secure comfort for the patient. I have in mind\\none patient who accepted 17 D. and saw J^ on Snellen test\\ncards with the same, yet was unable to, or rather would not,\\nwear them on the street, because, as she said, she could not\\nrecognize her intimate friends in the street with them on, on\\naccount of the distortion and contraction of their features.\\nShe had been wearing 10 D. before, and 12 D. was the\\nstrongest she could wear with comfort, though she saw much\\nworse with this than with the 17 D., so far as the test cards\\nwere concerned. In these very high degrees of myopia, there-\\nfore, there is no strict rule by which we may go, and we have\\nto seek the comfort of the patient. I usually reduce the glass\\nfrom the full correction, even for street wear, and give a still\\nweaker glass for reading. If the patient desires a full correc-\\ntion, I give it in a lorgnette, which can be used for a few\\nmoments at a time.\\nI have prescribed as high as 22 D., on one occasion, for\\na man who had about 26 D. of myopia. He had only one eye,\\nhowever, and the troublesome question of the relation between\\nconvergence and accommodation was eliminated in his case.\\nNot only did this glass minify objects in a marked degree, but\\nwhen his eye was looked at through the glass, it made the eye\\nappear very small to the observer, in fact, almost like a bead.\\nThere is another point about cases of high degree of myopia,\\nespecially where there are fundus lesions, that I wish to call\\nattention to here, and that is, that their vision seems much\\nworse when the stomach is upset or their general condition\\nmuch disturbed in any way. After they have quieted down,\\nthe vision comes up to what it was before the disturbance\\noccurred and they are again happy, though much concerned\\nabout their sight at the time of the disturbance. If this point", "height": "4257", "width": "2698", "jp2-path": "refractionofeye00davi_0172.jp2"}, "173": {"fulltext": "HIGH DEGREES OF MYOPIA 155\\nis not borne in mind, we might be induced by the patient to\\nchange the glasses unnecessarily at such time.\\nThe general health of these patients should be looked after\\nmost carefully, outdoor exercise ordered, rest to the eyes en-\\njoined, and close work for the eye for any considerable time\\nprohibited. In school children especially, who show any ten-\\ndency to progressive or malignant myopia, too much stress can-\\nnot be laid on the observance of general hygienic conditions,\\nsuch as much out-of-door exercises, short hours of study,\\nand then under the most favorable surroundings, good light,\\nupright position of the child at desk, etc., and proper correction\\nof errors of refraction. It is much better to let these children\\ngo through school with a little book learning, rather than to\\nlet them acquire knowledge, at the expense of eyesight, which\\nthey can never put into effect in after life. In fact, if it comes\\nto a question of school education or eyesight, stop the child\\nfrom school altogether at any rate, allow him the fewest of\\nhours of study possible, and this time to be divided by short\\nintervals, so as not to weary the eyes too much.\\nCase LXI. Large amount of myopia tuith a moderate amount\\nof astigmatism ivith the rule Axis of the astigmatism horizontal\\nin one eye and off from the horizontal in the other Asthenopia\\nRelief with glasses. June 1, 1896, Katie McQ., aged thirty-\\none years, in good health, comes on account of poor vision and\\nsome asthenopic symptoms. She is now wearing 9.50D.S\\nright eye and 9 D.s left eye.\\nOphthalmometer. Astigmatism with the rule, 3D., axis\\n105\u00c2\u00b0+ or 15\u00c2\u00b0- right eye 1.50 D., axis 90\u00c2\u00b0+ or 180\u00c2\u00b0- left eye.\\nTest cards and trial lenses.\\nR- V. Hts fi W. 8 D. 2.50 D. eyl., 15\u00c2\u00b0.\\nL- V. ^A^ If W. 11 D. 1 D. cyl., 180\u00c2\u00b0.\\nReads Jaeofer No. 1 at 9 inches.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0173.jp2"}, "174": {"fulltext": "156 THE REFRACTION OF THE EYE\\nOphthalmoscope. M. 11 D. at 105\u00c2\u00b0 and 8 D. at 15\u00c2\u00b0 right\\neye M. 13 D. left eye. There is a small posterior staphyloma\\nin the right eye, and a large one in the left, with spots of\\nchoroidal changes scattered over the fundus in each.\\nSecond test the patient accepted the same glasses as at\\nthe first test, and these were ordered.\\nIn this case the vision w^as considerably improved by the\\naddition of the cylindrical -to the spherical glasses, and the full\\ncorrection was ordered to be worn constantly, although the\\nmyopia was large in amount in the left eye. The glasses were\\nworn with perfect comfort.\\n1 wish to emphasize a point in this case which has already\\nbeen alluded to in this chapter in a general way, and that is,\\nthat the patient was able to wear these strong myopic glasses\\nfor near work with comfort. This is not always so, and in her\\ncase was due to the fact that she had worn almost full correc-\\ntion for her myopia since a child and, having her myopia\\ncorrected for the distance, she was compelled to use her accom-\\nmodation for near points. In this way the ciliary muscle was\\ndeveloped, and when she came to full correction in after years,\\nshe was able to wear the glasses with comfort.\\nCase LXII. Large amount of myopia; Small amount of\\nastigmatism^ hut marked increase of vision hy its correction Full\\ncorrection ivorn with comfort. March 15, 1898, Rebecca G., aged\\nseventeen, in good health, came to the clinic of Drs. Lewis and\\nVan Fleet, at the Manhattan Eye and Ear Hospital, for glasses,\\non account of poor vision, and because the glasses she had were\\nnot satisfactory. She had glasses fitted first when ten years of\\nage. These glasses were changed after five years time for the\\nglasses that she is now wearing, 11 D. in each eye.\\nOphthalmoyneter Astigmatism with the rule, 2D., 90\u00c2\u00b0+ or\\n180\u00c2\u00b0- each eye.\\n2*0 f^ W. 13 D. 1.50 D. cyl., 180\u00c2\u00b0o\\nL. V. 2^0 1^ W. 13 D. 1.50 D. cyl., 180\u00c2\u00b0.", "height": "4257", "width": "2811", "jp2-path": "refractionofeye00davi_0174.jp2"}, "175": {"fulltext": "ILLUSTRATIVE CASES 157\\nReads Jaeger No. 1, 5 to 15 inches.\\nThe cylindrical glasses increased the vision from to\\na marked increase when we consider the amount of myopia\\npresent and the small amount of astigmatism.\\nOphthalmoscope. Myopia 15 D. in each eye; also a small\\nposterior staphyloma in each eye.\\nSecond test the patient accepted the same glasses, and\\nthey were ordered for constant wear. Here again the glasses\\nwere very strong, but, as the patient had worn almost full\\ncorrection for some time before, they were worn with entire\\ncomfort.\\nMoreover, the cylindrical glasses, though small in amount\\nand with axis exactly at 180\u00c2\u00b0 in each eye (for this reason, as a\\nrule, their effect could easily have been gotten by tilting the\\nstrong spherical glass, \u00e2\u0080\u0094V6 D., slightly on the horizontal axes),\\nwere ordered in this case, because they so markedly increased\\nthe vision when added to the spherical glasses, and tilting of\\nthe spherical glasses did not give near so good vision.\\nCase LXIII. Comjjound myopic astigmatism in one eye;\\nSimple myopia of small a7nount in the other; Scopolamine used as\\na mydriatic. October 13, 1894, Miss M. R., aged thirty-one,\\nin good general health, consulted me for burning and itching\\nin the eyes, and for a strained feeling in them after using them\\nfor close work. She is a stenographer, and her eyes have\\ntroubled her more or less for the last year. She has no head-\\naches, but there is a mild conjunctivitis present.\\nOphthalmometer. Astigmatism with the rule, .75 D., axis\\n90\u00c2\u00b0+ or 180\u00c2\u00b0- right eye .50 D., axis 90\u00c2\u00b0+ or 180\u00c2\u00b0- left eye.\\nTest cards ajid trial lenses. _\\nR. V. 1^ ff W. 1 D. .25 D. cyl., 180\u00c2\u00b0.\\nL. V. If- W. .50 D.\\nReads Jaeger No. 1, 6 to 15 inches.\\nOphthalmoscope. M. 1 D. right eye INI. .50 D. left eye.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0175.jp2"}, "176": {"fulltext": "158 THE REFRACTION OF THE EYE\\nThere was some redness and injection of the conjunctiva\\nwith some scattering granulations on the palpebral conjunc-\\ntiva. On this account, and the weak minus glasses being\\naccepted, I thought perhaps the apparent myopia, as observed\\nby the ophthalmoscope and as manifested by the glasses\\naccepted, was due to a spasm of accommodation, even though\\nthe patient accepted the same glass time and again during the\\nexamination.\\nAs the patient was in a hurry for the glasses, I instilled a\\nsolution of scopolamine (gr. i to \u00c2\u00a7i), one drop in each eye,\\nevery five minutes, for six consecutive times, then waited one-\\nhalf hour and tested, with the following result\\nR. V. -^0% ft -50 cyi-. 180\u00c2\u00b0-\\nL. V. 3^0% ff W. .25 D. .25 D. cyl., 180\u00c2\u00b0.\\nThe ophthalmoscope and ophthalmometer gave the same\\nresults as at the first test.\\nThird test, three days later, when the patient was not\\nunder the influence of the mydriatic, resulted as follows\\nR. V. 1^ ff W. .75 D. .50 D. cyl., 180\u00c2\u00b0.\\nL. V. =|^:ft W.-.50D.\\nReads Jaeger No. 1, 6 to 15 inches.\\nThese last glasses were ordered, and have since been worn\\nwith comfort and satisfaction.\\nIn very low degrees of myopia it is impossible at times to\\ndecide with the ophthalmoscope or the retinoscope (without\\nthe use of a mydriatic) whether myopia is present or not.\\nAnd the mere acceptance of minus glasses by a patient is not\\npositive evidence by any means that myopia exists, as hyper-\\nmetropes, through spasm of accommodation, may, and often do,\\nwhen improperly tested, accept minus glasses. Myopia of a\\nlow degree, 1 D. and less, rarely needs correction, unless there\\nis a complicating astigmatism.", "height": "4251", "width": "2698", "jp2-path": "refractionofeye00davi_0176.jp2"}, "177": {"fulltext": "ILLUSTRATIVE CASES 159\\nCase LXIV. Compound myopic astigmatism in one eye;\\nSimple myopic astigmatism in the other Asthenopia marked;\\nPresbyopia. June 5, 1894, Mrs. M. S. C, aged fifty, in good\\ngeneral health, comes on account of severe headaches and\\npains in the eyes, especially after using the eyes for close\\nwork. She has worn glasses for fifteen or twenty years, con-\\nstantly for the last ten years.\\nOphthalmometer.- Astigmatism with the rule, 4 D., axis\\n125\u00c2\u00b0 or 35\u00c2\u00b0 right eye; 4 D., axis ^b\u00c2\u00b0 or 145\u00c2\u00b0 left\\neye.\\nThere is also some irregular astigmatism present in the\\nright eye.\\nTest cards and trial lenses.\\nR. V. 2% il W. 3.50 D. cyl., 35\u00c2\u00b0.\\nL. V. 1^ _ W. 4 D. 3.50 D. cyl., 145\u00c2\u00b0.\\nReads Jaeger No. 1, 6 to 13 inches with 2 D. added for\\nthe presbyopia, which in effect would be 2 D. 3.50 D.\\ncyl., 35\u00c2\u00b0 right, and -2D.- 3.50 D. cyl., 145\u00c2\u00b0 left.\\nOphthalmoscope. \u00e2\u0080\u0094M. 4 D. at 125\u00c2\u00b0 and Em. at 35\u00c2\u00b0 right\\neye M. 8 D. at B5\u00c2\u00b0 and 4 D. at 145\u00c2\u00b0 left eye.\\nThere are some diffuse corneal opacities on the cornea of\\nthe right eye, which accounts for the vision not being improved\\nin that eye.\\nA second test was made and agreed with the first, and\\nboth the distance and reading glasses were ordered. Both\\npairs of glasses have been worn with comfort.\\nIt is to the reading glasses I wish to call attention in this\\ncase. The patient, being fifty years of age, was presbyopic to\\nthe extent of 2 D. In the right eye she had simple mj^opic\\nastigmatism, and either a cross-cylindrical or a sphero-cylin-\\ndrical glass could be given. If a cross-cylindrical glass, it\\nwould take the following form: 2 D. cyl., 125\u00c2\u00b0 1.50 D.\\ncyl., 35\u00c2\u00b0. A glance at Fig. 69 shows why this is so. The", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0177.jp2"}, "178": {"fulltext": "160\\nTHE REFRACTIOX OF THE EYE\\nemmetropic meridian at 35\u00c2\u00b0 becomes presbyopic by 2 D., and\\nrequires 2 D. cylindrical glass at right angles to this meridian\\n(at 125\u00c2\u00b0) to correct it while the presbyopia of 2 D. neutral-\\nizes 2 D. of the 3.50 D. of myopia in the meridian at 125\u00c2\u00b0,\\nthus leaving 1.50 D. of myopia in this meridian still to be\\ncorrected, which requires 1.50 D. cyl., 35\u00c2\u00b0. But instead\\nof giving the cross-cylindrical glass, I chose the sphero-cylin-\\ndrical -(-2 D. 3.50 D. cyl., 35\u00c2\u00b0. First, because it was\\n145\\nR. E.\\nL. E.\\nFig. 69.\\ncheaper second, because the astigmatism was not very large\\nin amount, and the sphero-cylindrical glass in the right eye\\nwas made equal in weight with the opposite glass in the left eye.\\nThe two glasses, the cross-cjdindrical and the sphero-cylin-\\ndrical, are exactly the same in effect, except that the cross-\\ncylinders give a little wider field of vision. Thus the -f- 2 D.\\nspherical glass combined with the 3.50 D. cyl., 35\u00c2\u00b0, acts with\\nfull force along the axis of the minus cylinder, that is, in the\\nmeridian at 35\u00c2\u00b0, therefore acting as a -h 2 D. cyl., axis 125\u00c2\u00b0\\nand, at the same time, it neutralizes 2 D. of the 3.50 D. cyl. in", "height": "4257", "width": "2698", "jp2-path": "refractionofeye00davi_0178.jp2"}, "179": {"fulltext": "ILLUSTRATIVE CASES 161\\nthe meridian at 125\u00c2\u00b0, leaving but 1.50 D. of this cylindrical\\nglass to act in this (125\u00c2\u00b0) meridian, thus acting exactly the\\nsame as a 1.50 D. cyl., 35\u00c2\u00b0.\\nI go particularly into these changes of glasses rendered\\nnecessary by the presence of presbyopia in myopic astigmatism,\\nand have, in the chapter on simple myopic astigmatism, made\\ndiagrams of the changes of focus in the eye caused by pres-\\nbyopia in such cases. For beginners especially, I think it\\nmost desirable to make diagrams of the foci of the two chief\\nmeridians of the eye, as indicated by the examination made and\\nthe glasses accepted, just as I have done in most of the cases so\\nfar reported then to note the effect and changes of focus that\\n1 D. of presbyopia causes in each meridian separately or v^hat\\nchange 2 or 3 D., or whatever amount of presbyopia present\\nwould cause make diagrams of these latter foci, when no con-\\nfusion as to the proper reading glass can arise. For instance,\\nin the case just reported, right eye, for distant vision, the\\nmeridian at 35\u00c2\u00b0 is emmetropic, and focusses rays of light on\\nthe retina, while the meridian at 125\u00c2\u00b0 is mj^opic by 3.50 D.,\\nand focusses rays of light in front of the retina (see Fig. 69).\\nNow, a presbyopia of 1 D. would cause the focus in each\\nmeridian to recede to the extent of 1 D. (as measured by\\nglasses) for the reading distance, that is, the emmetropic merid-\\nian at 35\u00c2\u00b0 would focus back of the retina 1 D., and the my-\\nopic meridian at 125\u00c2\u00b0 would focus but 2.50 D.^ in front of\\nthe retina, instead of 3.50 as for the distance. With 1 D. of\\npresbyopia present in such a case as this, the correct reading-\\nglass would be, in cross-cylinders 1 D. cyl., 125\u00c2\u00b0 2.50 D.\\ncyl., 35\u00c2\u00b0 or, in sphero-cylindrical, 1 D. 3.50 D. cyl., 35\u00c2\u00b0.\\n1 In speaking of the meridians focussing- so many diopters in front or back of\\nthe retina, I am not unmhidful of the fact that we usually speak of the focus as\\nbeing at a certain linear distance in front or back of the retina. However,\\nas this linear distance is fairly well expressed, relatively so at least, by the power\\nof the glass it takes to correct the error, 1 have used the power of the glass as\\nexpressing these distances.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0179.jp2"}, "180": {"fulltext": "162 THE REFRACTION OF THE EYE\\nFor 2 D. of presbyopia, which is actually present in this\\ncase, we have already shown what the correct reading glasses\\nwould be (see test). For 3 D. of presbyopia, the focus for\\nthe meridian at 35\u00c2\u00b0 for reading would be 3 D. back of the ret-\\nina, and for the meridian at 125\u00c2\u00b0, .50 D. in front of the retina.\\nFor correction, in cross-cylinders, it would take 3 D. cyl.,\\n125\u00c2\u00b0 .50 D. cyl., 35\u00c2\u00b0 or, in sphero-cylindrical, -f 3 D.\\n3.50 D. cyl., 35\u00c2\u00b0 (or, if we chose to give a minus sphere\\nand a plus cylinder, \u00e2\u0080\u0094.50 D. 3.50 D. cyl., 125\u00c2\u00b0, which would\\nbe a lighter glass in this instance). For 4 D. of presbyopia,\\nthe myopic astigmatism would be entirely neutralized, and the\\nfocus for reading in the meridian at 35\u00c2\u00b0 would be 4 D. back of\\nthe retina, while the focus for the meridian at 125\u00c2\u00b0 would also\\nbe back of the retina, to the extent of .50 D. In effect, there-\\nfore, for the reading distance, the patient is compound hyper-\\nmetropic astigmatic, and would require for a reading glass,\\nright eye, .50 D. 3.50 D. cyl., 125\u00c2\u00b0.\\nIn the present case, the left eye has 4 D. jof myopia, in\\naddition to the astigmatism of 3.50 D. Of course, it would\\ntake 4 D. of presbyopia to neutralize this myopia, before the\\nastigmatism would be affected, and, after which, exactly the\\nsame change in glasses for the left eye would be required as\\nhas taken place in the right eye.\\nI am aAvare of the fact that this method of making diagrams\\nof the foci of the chief meridians of the eye for the distance,\\nthen noting the change in focus brought about in each meridian\\nfor a certain amount of presbyopia, takes more time than the\\none of simple algebraic equations but it has the great advan-\\ntage of fixing the examiner s attention on the real condition\\nand foci of the different meridians of the eye, thus making it\\na concrete case. With algebraic equations to ascertain the cor-\\nrect reading glass, it becomes a matter of abstract fact to a\\ncertain extent, and the observer, if he be a beginner, does not\\nkeep in mind the real condition of the eye, but fits the glasses", "height": "4257", "width": "2698", "jp2-path": "refractionofeye00davi_0180.jp2"}, "181": {"fulltext": "ANTIMETROPIA 163\\nempirically. For example, take the left eye in the present case,\\nwhere the distance glass accepted is 4 D. 3.50 D. cyl.,\\n145\u00c2\u00b0. At fifty years of age, with 2 D. of presbyopia present,\\nthe patient requires 2 D. added to the distance glasses to get\\nthe correct reading glass. Algebraically it is\\n-4D. -3.50D. cyl., 145\u00c2\u00b0.\\n2D.\\n-2D.- 3.50 D. cyl., 145\u00c2\u00b0.\\nFor 4 D. of presbyopia it would be\\n-4 D. -3.50 D. cyl., 145\u00c2\u00b0.\\n4-4D.\\n3.50 D. cyl., 145\u00c2\u00b0.\\n(I)\\n(11)\\nNow this is perfectly correct in each instance, but if the\\nexaminer is not familiar with optics, unless he makes a diagram\\nof the change of focus brought about by the presbyopia for the\\nreading point, he will not likely have a clear idea of the real\\ncondition of the eye.\\nAntimetropia\\nThe word anisometropia is often used for, and intended to\\nconvey the meaning of, the word antimetroina. Antimetropia\\nmeans opposite state of refraction of the two eyes, myopic in\\nnature in one eye and hypermetropic in the other, and is from\\nthe three Greek words, avri^ opposite, ixerpov^ measure, and\\noyln vision while anisometropia is from avtcro^, unequal,\\njjLeTpov^ measure, and oyjrt^^ vision, and means an loiecpial state\\nof refraction of the two eyes that is, both eyes being either\\nhypermetropic or myopic, one of the eyes is more hj perme-\\ntropic or myopic than the other. Therefore, there is a distinct\\ndifference in the meaning of the two words, and they also indi-\\ncate quite different conditions in the eyes, and they should not,\\non that account, be confounded one with the other, as is so often", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0181.jp2"}, "182": {"fulltext": "164 THE REFRACTION OF THE EYE\\ndone. Anisometropia is quite common, while antimetropia is\\nrare.\\nAntimetropia is one of the most annoying errors of refrac-\\ntion, outside of conical cornea and irregular astigmatism, which\\nare really pathological conditions rather than refractive, that\\nwe have to deal with. In some cases, in fact, one eye has to be\\nfitted by itself, while the other has to be left alone, as the two\\ncannot be made to work together. And this happens oftenest\\nwhere the error is of large amount in one eye, associated with\\namblyopia while the other eye has only a small or moderate\\nerror of refraction and with no amblyoj)ia.\\nThere are three or four reasons why antimetropes have\\ntrouble in using the two eyes together for binocular single\\nvision. First, in such cases, it is difficult to fuse the poor\\nimage of the amblyopic eye with the clear image of the good\\neye so as to make but a single image in the brain center\\nsecond, for objects near at hand, it is difficult to converge the\\nmyopic or long eyeball to the same extent as the hypermetropic\\nor short eyeball, again rendering single binocular vision diffi-\\ncult thirds if the myopia is of high degree and fully cor-\\nrected, the patient will have difficulty i;i accommodating for\\nnear objects with that eye as compared with the hypermetropic\\neye, for its ciliary muscle is much weaker than that of the\\nhypermetropic eye fourth, the images of objects are different\\nin size in the two eyes.\\nSome antimetropes are so fortunate as to be able to use the\\nhypermetropic eye for distant vision and the myopic eye for\\nnear vision, thus using the eyes alternately and singly, and not\\ntogether. In this way they are able to go without glasses, and\\nmake this, what to many is a veritable burden, an advantage\\nin their favor over ordinary mortals. But they are the rare\\nexceptions.\\nIn many of these cases, where one eye is used constantly -to\\nthe exclusion of the other, the unused eye drops out of the line", "height": "4262", "width": "2698", "jp2-path": "refractionofeye00davi_0182.jp2"}, "183": {"fulltext": "ANTIMETROPIA 165\\nof vision and usually squints outward. However, I have\\nknown the amblyopic eye, which was highly myopic, to squint\\ninward.\\nMy plan of procedure in antimetropia is to fit the eyes\\nseparately, just as in other cases, and whatever glasses are\\naccepted, have the patient wear them faithfully for a period of\\none month at least. If they do not give relief, I then usually\\nleave the correction on the better eye, and place a plain glass\\nin front of the bad eye. Each case, to a certain extent, is a\\nlaw unto itself, however, and must be dealt with accordingly.\\nA few concrete cases will give some idea how these patients\\nare to be managed.\\nCase LXV. Antimetropia with hlejjharitis marginalis\\nSimple liypermetropic astigmatism m one eye and simple myopic\\nastigmatism in the other ivith the rule in each eye. November\\n19, 1895, Nellie R., aged twenty-two years, in good general\\nhealth, consulted me on account of great pain in the eyes,\\naccompanied with severe headaches. She wanted very much\\nto be relieved of redness of the eyelids, which remained irri-\\ntated and more or less inflamed all the time.\\nOphthalmometer. Astigmatism with the rule, 1 D., axis\\n90\u00c2\u00b0+ or 180\u00c2\u00b0- in each eye.\\nTest cards and trial lenses. The vertical lines on the\\nclock-dial were seen plainest with the right eye, and the hori-\\nzontal lines were seen best with the left eye.\\nR. Y. 1^ I^W. .50 D. cyl., 180\u00c2\u00b0.\\nL. Y. |o 4- i| W. .50 D. cyl., 90\u00c2\u00b0.\\nReads Jaeger No. 1 from 6 to 17 inches.\\nOphthalmoscope. \u00e2\u0080\u0094M. .75 D. at 90\u00c2\u00b0 and Em. at 180\u00c2\u00b0 right\\neye Em. at 90\u00c2\u00b0 and H. .75 D. at 180\u00c2\u00b0 left eye.\\nA saturated solution of boracic acid was ordered as a wash\\nfor the eyelids, to be used twice a day and the yellow oxide", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0183.jp2"}, "184": {"fulltext": "166\\nTHE REFEACTION OF THE EYE\\nof mercury ointment (gr. viii to Si vaseline) was ordered to be\\nrubbed on the eyelids at bedtime.\\nAfter a week, in which time the lids improved but little,\\na second test was made for glasses. The patient accepted\\nexactly the same glasses as at the first test. Ordered for con-\\nstant wear: .50D. cyl., 180\u00c2\u00b0 right eye, and .50 D. cyl.,\\n90\u00c2\u00b0 left eye. Within a month the eyelids were well of their\\ninflammation, the pains in the eyes and the headaches gone,\\nand the patient happy. She has continued to wear the glasses\\n180\\n180\\nR. E.\\nL. E.\\nFig. 70.\\never since with great satisfaction. With large errors of refrac-\\ntion of this nature, however, glasses do not usually give so\\ngood a result.\\nAttention may be called to the reading of the ophthal-\\nmometer in this case. The instrument read exactly the same\\namount and the same axis of astigmatism in each eye. Fol-\\nlowing my routine practice of beginning the test with weak\\nplus glasses (cylinders where there is astigmatism), I found,\\nthey would not be accepted by the right eye. I then tried a", "height": "4249", "width": "2789", "jp2-path": "refractionofeye00davi_0184.jp2"}, "185": {"fulltext": "ANTIMETROPIA 167\\nweak minus cylinder, axis 180\u00c2\u00b0, as indicated by the instrument,\\nand it was accepted, a .50 D. cyl., 180\u00c2\u00b0, giving the best\\nvision. Although I found simple myopic astigmatism in the\\nright, I again followed my routine method of trying plus\\nglasses first on the left eye, and found that they were accepted,\\na +.50 D. cyl., 90\u00c2\u00b0, giving the best vision. Had minus cylin-\\ndrical glasses been tried first on the left eye, I am convinced\\nshe would have accepted them, as she had on previous tests,\\nand from which glass she got no relief from her asthenopia or\\nred eyelids.\\nIt must always be remembered that the ophthalmometer\\ndoes not reveal to us the nature of the error of refraction,\\nthat is, if hypermetropic or myopic, but simply the\\naxis and the amount of the corneal astigmatism. But, with\\nthis much known, by following the routine method already\\ngiven in detail in previous pages of this book, nearly\\nevery case can be fitted correctly and without the use of a\\nmydriatic.\\nCase LXVI. Antimetropia Amblyopia to some extent; Sim-\\nple hypermetropic astigmatism in one eye^ and simple myojpic astig-\\nmatism in the other^ with the rule in each. February 13, 1897,\\nM. F., aged eighteen, in good health, consulted me for glasses\\non account of poor vision, and because of pain in the eyes and\\nheadaches when she persists in using the eyes.\\nOphthalmometer. Astigmatism with the rule, 2 D., axis\\n75\u00c2\u00b0 or 165\u00c2\u00b0 right eye 2D. with the rule, axis 105\u00c2\u00b0 or\\n15\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nR. V. f 1^ W. 1.75 D. cyl., 75\u00c2\u00b0.\\nL. V. f^ 20. W.- 1.75 D. cyl., 15\u00c2\u00b0.\\nReads Jaeger No. 1 from 6 to 12 inches, and has single\\nbinocular vision.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0185.jp2"}, "186": {"fulltext": "168\\nTHE REFRACTIOX OF THE EYE\\nEm. at 75\u00c2\u00b0 and H. 2 D. at 165\u00c2\u00b0 right\\nOphtJialmoscope.\\neye M. 2 D. at 105\u00c2\u00b0 and Em. at 15\u00c2\u00b0 left eye.\\nA second and a third test resulted in the patient accepting\\nthe same glasses as at the first test. Ordered 1.75 D. cyl.,\\n165\\nR. E.\\nL. E.\\nFig. 71.\\n75\u00c2\u00b0 right eye, 1.75 D. cyl., 15\u00c2\u00b0 left eye. These glasses have\\nbeen worn for more than a year, with relief from her asthenopic\\nvision.\\nCase LXVII. Antimetropia Asthenopia; Simple hyperme-\\ntropic astigmatism in one eye^ and compound myopic astigmatism\\nin the other^ ivith the ride in each. August 11, 1896, James\\nMcG., aged thirty years, came to the clinic of Drs. Lewis and\\nVan Fleet, at the Manhattan Eye and Ear Hospital, because\\nof pain in his eyes and on account of severe headaches. His\\neyes have always given him trouble, both for far and near\\nvision. The pains in the head are confined to the frontal\\nregion chiefly.", "height": "4240", "width": "2698", "jp2-path": "refractionofeye00davi_0186.jp2"}, "187": {"fulltext": "ANTIMETROPIA\\n169\\nOphthalmometer. Astigmatism with the rule, 1 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 in each eye.\\nTest cards and trial lenses.\\nR. Y. =|\u00c2\u00a7-:l|W.+.50 D. cyl.,90\u00c2\u00b0.\\nL. V. If ff W. 1 D. .50 D. cyl., 180\u00c2\u00b0.\\nReads Jaeger No. 1, 5 to 12 inches.\\nOphthalmoscope. \u00e2\u0080\u0094^m. at 90\u00c2\u00b0 and H. .50 D. at 180\u00c2\u00b0 right\\neye M. 1.50 D. at 90\u00c2\u00b0 and M. 1 D. at 180\u00c2\u00b0 left eye.\\n180\\nR. E.\\nFig. 72.\\nSecond test the patient accepted exactly the same glass\\nas at the first test, and it was ordered. It took two weeks\\npersistent wearing before the patient got accustomed to the\\nglasses but at the end of that time his eyes were entirely\\ncomfortable and his headaches relieved. After the first month\\nthe patient was lost sight of.\\nCase LXVIIT. Antimetropia Compound hiipcrmctropic\\nastigmatism in one eye and compound myopic asti(/niatis)n in the\\nother, against the rule in the inyopic eye and with the rule in the", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0187.jp2"}, "188": {"fulltext": "170 THE REFRACTION OF THE EYE\\nhypermetropic eye; Marked asthenopia relieved ivith glasses.\\nNovember 19, 1895, Harriet W., aged twelve years, in good\\nhealth, consults me on account of blurred vision and headaches,\\nespecially annoying in the afternoon at school. She has worn\\nglasses, but without relief.\\nOphthalmometer. Negative right eye astigmatism with\\nthe rule, .75 D., axis 90\u00c2\u00b0 180\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nR. V. 1^^ not improved.\\nL. V. f^:||W.+ l.D.\\nReads Jaeger No. 1 from 5 to 12 inches. Signs of spasm\\nof accommodation are j)i^esent.\\nOphthalmoscope. \u00e2\u0080\u0094M. 1 D. right eye; H. .50 D. at 90\u00c2\u00b0\\nand H. 1 D. at 180\u00c2\u00b0 left eye.\\nOn account of a conjunctivitis, an astringent wash was\\nordered for the eyes, and the patient directed to come again in\\nthree days.\\nSecond test the ophthalmometer read the same as at the\\nfirst test.\\nTest cards and trial lerises.\\nU U -5^ -50 1^- cyi., 105\u00c2\u00b0.\\nL. V. 1^ ff W. .50 D. .50 D. cyl., 90\u00c2\u00b0.\\nReads Jaeger No. 1, 5 to 15 inches.\\nOphthalmoscope. \u00e2\u0080\u0094U. .50 D. at 105\u00c2\u00b0 and M. 1 D. at 15\u00c2\u00b0\\nright eye; H. .50 D. at 90\u00c2\u00b0 and H. ID. at 180\u00c2\u00b0 left eye.\\nOn a third test the patient accepted the same glasses as\\non the second test, and they were accordingly ordered. They\\nhave been worn for more than two years with relief from all\\nasthenopic symptoms.\\nIn this case the ophthalmometer showed no corneal astig-\\nmatism in the right eye, and, as usual in such cases, the patient\\naccepted a cylindrical glass against the rule", "height": "4241", "width": "2698", "jp2-path": "refractionofeye00davi_0188.jp2"}, "189": {"fulltext": "ANTIMETROPIA\\n171\\nOn the first test there was some spasm of accommodation,\\ndue to irritation of the eye from a mild conjunctivitis. After\\na few days treatment this disappeared, the second and third\\ntests agreed, and the glasses were ordered.\\n180\\nR. E.\\nL. E.\\nFig. 73.\\nCase LXIX. Antimetropia Mixed astigmatism rights and\\nCompound myopic astigmatism left^ eye Head carried to the right\\nside; Asthefioj^ia Relief with glasses. November 22, 1897,\\nMary McG., aged twenty-three years, in good health, consulted\\nme on account of headaches and pains in the eyes. She has\\na tendency to hold her head to the right, especially for close\\nwork. Her left eye has troubled her a great deal for the last\\neighteen months, and sometimes sharp pains shoot through it.\\nThe left eye is very sensitive to bright light and heat.\\nOphthalmometer. Astigmatism with the rule, 2.50 D., axis\\n45\u00c2\u00b0 or 135\u00c2\u00b0- right eye 2.50 D., axis 60\u00c2\u00b0 or 150\u00c2\u00b0- left eye.\\nTest cards and trial lenses.\\n2 00 10 W. 2 D. cyl., 45\u00c2\u00b0 .50 D. cyl., 135\u00c2\u00b0.\\nR. V. -2JL 2\\n2^0 To^ W. 10 D. 2. D. cyl., 150\u00c2\u00b0.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0189.jp2"}, "190": {"fulltext": "172\\nTHE REFRACTIOX OF THE EYE\\nReads Jaeger No. 1, 6 to 10 inches, with the right eye.\\nSingle binocular vision is not present.\\nOphthalmoscope. YL. I D, at 135\u00c2\u00b0 and M. ID. at 45^\\nright eye; M. 13 D. at 60\u00c2\u00b0 and 11 D. at 150\u00c2\u00b0 left eye.\\nR. E.\\nL. E.\\nFig. 74.\\nSecond test two days later the ophthalmometer gave the\\nsame reading.\\nTest cayxJs and trial lenses.\\nR V -2JL\\n\u00c2\u00b1v. V 2\\nL V -2-\\n2 00\\n1^ W. 1 D. cyl., 45\u00c2\u00b0 -ID. cyl., 135\u00c2\u00b0.\\n__2_o_ W 1 D\\n100\\n2D. cyl., 150\u00c2\u00b0.\\nA third test coincided with the second, and the glasses were\\nordered. The patient has been greatly benefited, the pain in\\nthe eyes and head disappeared after about two weeks time\\nand after the first month she has been able to hold her head\\nstraight. She wore these glasses continuously till November\\n22, 1898, just one year, when she returned, complaining of\\npain in the right eye. On examination I found that the\\nastigmatism had increased one-quarter of a diopter, and had", "height": "4249", "width": "2698", "jp2-path": "refractionofeye00davi_0190.jp2"}, "191": {"fulltext": "ANTIMETROPIA 17g\\nchanged axis to the extent of 10\u00c2\u00b0, that is, from 45\u00c2\u00b0 to 35\u00c2\u00b0,\\nand from 135\u00c2\u00b0 to 125\u00c2\u00b0, respectively. The patient accepted\\n1 D. cyl., 35\u00c2\u00b0 1.25 D. cyl., 125\u00c2\u00b0 right eye. The left eye\\nhad not changed, and the old glass was left. The new glass\\nhas relieved the pain in the right eye, and the patient is again\\ncomfortable, and carries her head perfectly straight.\\nCase LXX. Antimetropia Simple Jiypermetropia right eye;\\nSimple myopia of large a7noimt ivitli convergent strabismus left eye\\nCorrection of strabismus with glasses without operation. Marcli\\n10, 1892, Emma S., aged eighteen years, in poor health, con-\\nsulted me on account of a trachoma and convergent strabismus\\nof the left eye. She is anaemic and much run down, has but\\npoor appetite, and is now under treatment for nervous dyspep-\\nsia. There is considerable inflammation in the lids, with some\\ndischarge.\\nAfter five months treatment of the lids with the usual local\\napplications, and with general tonics, the patient s condition\\nwas greatly improved in every way. At the end of this time\\nI gave the first test for glasses as follows\\nOphthalmometer. Astigmatism with the rule, .50 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 each eye.\\nTest cards and trial lenses.\\nT. V -2JL W _ 1 B D\\n200*200 \u00c2\u00b1u J^.\\nReads Jaeger No. 1, 6 to 15 inches, with the right e3^e.\\nOphthalmoscope. H. 1.50 D. right eye; M. 17 D. left eye,\\nwith posterior staphyloma, choroiditis, and floating bodies in\\nthe vitreous.\\nSecond test: this corresponded with the first, and ID.\\nright eye and 10 D. left eye were ordered, to be worn con-\\nstantly. After about six weeks time the left or myopic eye\\nno longer squinted, which was most gratifying both to the\\npatient and myself.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0191.jp2"}, "192": {"fulltext": "174 THE REFRACTIOX OF THE EYE\\nThe patient has been under my observation for six years^\\nand the eyes remain perfectly straight, although she has not\\nsingle binocular vision.\\nI account for the correction of the convergent strabismus in\\nthe myopic eye by means of glasses in this case in exactly the\\nway as the ordinary convergent squint of hypermetropia is\\ncorrected b}^ glasses, as follows the patient, being in poor\\nhealth and having 1 D. of manifest h3^permetropia in the right\\neye, converged the left amblyopic eye unduly inward in order\\nto assist the accommodation in the right eye, that is, squinted\\nthe left eye inward. When the manifest hypermetropia in the\\nright eye was corrected with a plus glass, there was no need\\nof extra accommodative power in that eye, so the patient no\\nlonger squinted or converged the left eye too far inward, but\\nrelaxed this effort, and the left eye became straight that is,\\nparallel with the right.", "height": "4247", "width": "2698", "jp2-path": "refractionofeye00davi_0192.jp2"}, "193": {"fulltext": "CHAPTER VII\\nMIXED ASTIGMATISM ILLUSTRATIVE CASES\\nPerhaps mixed astigmatism is the most troublesome error\\nof refraction which we are called upon to correct, and many\\noculists never attempt to correct a case of mixed astigmatism\\nwithout the use of a mydriatic. To beginners, such cases are\\npuzzling, and the examiner is often led to make prolonged and\\nunnecessary tests. As for myself, I never think of using a\\nmydriatic in mixed astigmatism, unless there is a tendency to,\\nor an actual spasm of, accommodation, any more than I do in\\ncases of simpler errors of refraction.\\nThe ophthalmometer scores one of its greatest triumphs in\\njust these cases, and does away with the necessity and bother\\nof using a mydriatic. I grant, however, retinoscopy is a\\nvaluable method of testing where a mydriatic is used. But\\nthe use of a mydriatic is just what we wish to avoid if pos-\\nsible. With the use of the ophthalmometer and a routine\\nmethod of testing the cases, we are able, in the great majority\\nof cases, to avoid the use of a mydriatic altogether. On the\\nother hand, to make retinoscopy effective in these cases, or in\\nany other for that matter, a mydriatic must be used.\\nI begin my test in these cases in exactly the same manner\\nas in all others, that is, I ascertain with the ophthalmometer\\nthe amount and axis of the corneal astigmatism. Sa} for\\nexample, the instrument reads astigmatism with the rule,\\n2.50 D., axis 90\u00c2\u00b0 or 180\u00c2\u00b0 The first glass that I try is\\na .25 D. cyl., 90\u00c2\u00b0. If this improves vision, I gradually\\nincrease its strength .25 D. at a time) until the plus cylin-\\n175", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0193.jp2"}, "194": {"fulltext": "176 THE REFRACTION OF THE EYE\\nclrical glasses cease to improve the vision. By way of illus-\\ntration in this supposed case, say the patient accepted 1 D.\\ncyl., 90\u00c2\u00b0, and the vision was improved from y^JL to |-Q-, but that\\nwhen a +1.25 D. cyl., 90\u00c2\u00b0, was tried it made the vision worse.\\nNow, since the instrument showed the patient to have 2.50 D.\\nof astigmatism, and as he accepted only 1 D. of that amount\\nin plus glasses, I would immediately suspect mixed astigma-\\ntism, especially if a weak plus spherical glass in addition to\\nthe cylinder did not further improve vision. I would then\\ntry a .25 D. cyl., 180\u00c2\u00b0, that is at right angles to the plus\\ncylinder. If this improved vision, it should be increased in\\nstrength, a quarter diopter at a time, until the vision ceased\\nto be improved thereby, being careful to stop with the weakest\\nminus glass that gave the best vision. We will say \u00e2\u0080\u0094ID.\\ncyl., 180\u00c2\u00b0, in this instance, and that the vision was further im-\\nproved over that obtained by the plus cylinder alone, to\\nwith the two cylinders combined. This would indicate a case\\nof mixed astigmatism, equally divided as to hypermetropia\\nand myopia, or 1 D. of each, and 2 D. of astigmatism all\\ntold. Deducting .50 D. from the reading of the ophthal-\\nmometer (which was 2.50 D.), since the astigmatism was^\\nwith the rule, it leaves just 2 D, of astigmatism to be\\ncorrected. Of course, a second test should be given in all\\ncases of mixed astigmatism, and if the glasses on the sec-\\nond test agree with the first test, I do not hesitate to give\\nthem. Sometimes it is necessary to give a third test. I may\\nsay it is exceptional for me not to be able to fit such cases\\nwithout the use of a mydriatic.\\nKnowing the amount of the astigmatism from the reading\\nof the instrument, we can readily see how close the astigma-\\ntism, as indicated by the glasses accepted, corresponds with\\nit. In this way we are put on guard against giving too strong\\nminus cylinders in such cases, as is often done, especially\\nwhere the test is improperly begun with minus glasses.\\nI", "height": "4260", "width": "2789", "jp2-path": "refractionofeye00davi_0194.jp2"}, "195": {"fulltext": "MIXED ASTIGMATISM 177\\nSince it is of great importance in ordinary cases to begin the\\ntest for glasses with plus glasses, how much more important is\\nit to begin the test with plus glasses in these cases of mixed\\nastigmatism And we must do so, unless we wish to give too\\nstrong minus cylinders, or use a mydriatic, neither of which\\nalternatives is necessary. In fact, I have seen not a few cases\\nof mixed astigmatism fitted with minus cylindrical glasses.\\nSo easy is it to fall into this error, that I venture to present\\na diagram of such a case, and in this way demonstrate how\\nsuch mistakes are made. I thus hope to keep beginners from\\nblundering.\\nAs an example, we will take the case just cited above,\\nwhere the ophthalmometer read astigmatism Avith the rule,\\n2.50 D., axis 90\u00c2\u00b0 or 180\u00c2\u00b0 and the patient accepted\\n1 D. cyl., 90\u00c2\u00b0 -ID. cyl., 180\u00c2\u00b0.\\nNow, if instead of beginning the test with weak plus cylin-\\ndrical glasses, as we did, say we began with minus cylinders,\\nand gradually increased them in strength. In place of stop-\\nping with 1 D. cyl., 180\u00c2\u00b0, the exact correction of the\\nmyopic astigmatism, the patient would most likely have ac-\\ncepted 2D. cyl., 180\u00c2\u00b0, the total amount of the astigmatism\\npresent. In this way the mixed astigmatism is converted into\\na simple hypermetropia of 1 D.\\nA glance at Fig. 75 will show how this is brought about.\\nThe \u00e2\u0080\u00942D. cyl., 180\u00c2\u00b0, not only corrects the myopia of ID. in\\nthe vertical meridian, but diverges the rays in that meridian\\n1 D. back of the retina. Now, since the eye is already hyper-\\nmetropic 1 D. in the horizontal meridian, Ave CAadently have\\nin effect 1 D. of simple lij^permetropia present; which induced\\nhypermetropia, by the Avay, the patient can and often will cor-\\nrect by the use of the ciliary muscle, since he uoav can use it\\nin its entire circumference. Not onl}^ can the patient do this,\\nbut, if his accommodative power is strong, he sometimes does\\nit with comfort. Hence the relief for a time from asthenopia", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0195.jp2"}, "196": {"fulltext": "178\\nTHE REFRACTION OF THE EYE\\nsometimes in mixed astigmatism, even with simple minus\\ncylindrical glasses.\\nIncidentally, I might say, a case similar in effect to this is\\nwhere a patient with simple hypermetropic astigmatism accepts\\na simple myopic cylindrical glass. For example, say a patient\\nshould wear a 1 D. cyl., 90\u00c2\u00b0, to correct a simple hyperme-\\ntropic astigmatism of that amount. Now instead of this he\\nwill sometimes accept ID. cyl., 180\u00c2\u00b0, especially so if minus\\n180\\n180\\nFig. 75. (A) Before correction. (B) After correction with \u00e2\u0080\u00942D. cyl., axis 180\u00c2\u00b0^\\nthe mixed astigmatism is converted into a simple hypermetropia of 1 D.\\ncylindrical glasses are begun with. The ID. cyl., 180\u00c2\u00b0,\\nconverts the patient s simple hypermetropic astigmatism into\\na simple hypermetropia of 1 D. (see Fig. 76).\\nThe patient by means of his accommodative power can\\ncorrect this simple hypermetropia (as produced by the minus\\ncylinder) with comfort at times, because he can use the whole\\nof the ciliary muscle regularly while he could not correct the\\nsimple hypermetropic astigmatism without discomfort, since,\\nin that case, it must contract irregularly to act on the horizon-\\ntal meridian of the lens without at the same time acting on the", "height": "4249", "width": "2698", "jp2-path": "refractionofeye00davi_0196.jp2"}, "197": {"fulltext": "MIXED ASTIGMATISM\\n17^\\nvertical meridian, which is emmetropic and should be let alone.\\nSuch is the simple explanation of these cases. No stronger-\\nplea could be urged for the beginning of all tests with plus\\nglasses, I am sure.\\nTo recapitulate most cases of mixed astigmatism can be\\ncorrectly fitted with glasses without the use of a mydriatic,,\\nprovided that first, the amount and axis of the corneal astig-\\nmatism be ascertained next, that the test for glasses be begun\\nFig. 76.\u00e2\u0080\u0094 (A) Before correction. (B) After correction with \u00e2\u0080\u0094ID cyl., 180\u00c2\u00b0, hy\\nwhich the simple hypermetropic astigmatism is converted into a simple hyper-\\nmetropia of 1 D.\\nwith weak plus glasses and their strength gradually increased i\\nand finally minus glasses tried.\\nThe chief indication for a mydriatic in such cases, as in all\\nother cases of refractive error, is a spasm of accommodation.\\nThe means of detecting spasm of accommodation have already\\nbeen pointed out elsewhere, so we need not consider them\\nCase LXXIo 3Iixed astigmatism of large amount and with\\nthe rule m each eye; Asthenopia; Relief ivitli glasses. April -1.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0197.jp2"}, "198": {"fulltext": "180 THE refractio:n^ of the eye\\n1893, Miss S. A., aged twenty-two years, in good general\\nhealth, has had trouble with her eyes for the last six years.\\nShe now complains of having to hold the print too close to her\\neyes when she reads, also of headache and pain in the eyes\\nafter reading or sewing. She has three brothers and one sister,\\nnone of whom are troubled with their eyes.\\nOphtliahnometer. Astigmatism with the rule, 4 D., axis\\nT5\u00c2\u00b0 or 165\u00c2\u00b0 right eye 5 D., axis 95\u00c2\u00b0 or 5\u00c2\u00b0 left eye.\\nTest cards and trial\\nR. Y. 2^0 1^ W. 1.75 D. cyl., 75\u00c2\u00b0 1.75 D. cyl., 165\u00c2\u00b0.\\nL- 2W I* W. 3.25 D. cyl., 95\u00c2\u00b0 1 D. cyl., 5\u00c2\u00b0.\\nReads Jaeger No. 1 from 8 to 15 inches.\\nOphthalmoscoj^e. \u00e2\u0080\u0094M. 2D. at 75\u00c2\u00b0 and H. 2D. at 165\u00c2\u00b0 right\\neye M. 1 D. at 95\u00c2\u00b0 and H. 4 D. at 5\u00c2\u00b0 left eye.\\nSecond test three days later the ophthalmometer gave ex-\\nactly the same reading as at the first test.\\nTest cards and trial\\nI^- 2% 1* 2 D. cyl., 75\u00c2\u00b0 1.50 D. cyL, 165\u00c2\u00b0.\\nL. V. 2VV 1^ W. 3.50 D. cyl., 95\u00c2\u00b0 .75 D. cyl., 5\u00c2\u00b0.\\nThe ophthalmoscope agreed practically with the first exami-\\nnation. I ordered the glasses that were accepted on the second\\ntest in sphero-cylinders, to wit: 1.50 D. -f 3.50 D. cyl., 75\u00c2\u00b0\\nright; and .75 D. +4.25 D. cyl., 95\u00c2\u00b0 left. These glasses\\nhave been worn with great satisfaction from the first, and have\\nnot been changed.\\nIt will be noticed that I ordered a sphero-cylindrical glass\\ninstead of cross-cylinders. In this instance I gave sphero-\\ncylinders, because by actual trial in the trial frames the sphero-\\ncylinders were more comfortable to the patient and gave equally\\nas good vision. It will be seen also that I gave a minus sphere\\nwith a plus cylinder. There was a reason for this. In this\\ncase the minus spheres combined with plus cylinders is a", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0198.jp2"}, "199": {"fulltext": "MIXED ASTIGMATISM\\n181\\nmuch lighter glass than had we given plus spheres with minus\\ncylinders. For example, take the glass for the left eye\\n.75 D. 4.25 D. cyl., 95\u00c2\u00b0, is a much lighter glass than\\n3.50D. cyl., 95\u00c2\u00b0- 4.25 D. cyl., 5\u00c2\u00b0, though the glasses are\\nidentical in effect with each other, as they are, indeed, with\\nthe cross-cylinders, 3.50 D. cyl., 95\u00c2\u00b0 .75 D. cyl., 5\u00c2\u00b0, from\\nwhich they are transposed.\\nWhere we have mixed astigmatism in one eye only, when\\nwe convert a cross-cylinder into a sphero-cylinder we have to\\nR. E.\\nL. E.\\nFig. 77.\\npay some regard to the axis of the cylinder in the other eye,\\nif astigmatism of a simple or compound nature is present a\\npoint which will be illustrated by cases to follow.\\nIn small and moderate degrees of mixed astigmatism, instead\\nof giving cross-cylinders, a sphero-cylinder is most often to be\\npreferred, for the reason that it is a cheaper glass than the\\ncross-cylinders. But in high degrees of mixed astigmatism\\ncross-cylinders are to be preferred to sphero-cylinders, because\\nthey give a broader field of vision. The method of converting", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0199.jp2"}, "200": {"fulltext": "182 THE REFRACTIOX OF THE EYE\\ncross-cylinders into sphero-cylinders is a very simple one if you\\nplease, the simplest of algebraic equations. For the benefit of\\nany one who may not understand algebraic equations, I may say\\nthat I shall use the simplest terms, so that even they may\\nunderstand the method. I will give a concrete case in order\\nto illustrate the more plainly. Take the last case cited, right\\neye, where the patient accepts a 2 D. cyl., 75\u00c2\u00b0 1.50 D. cyl.,\\n165\u00c2\u00b0. To convert this into a sphero-cylinder (plus sphere witlx\\na minus cylinder) give a 2 D. sphere in place of the 2 D. cyl.,,\\nthen transpose 2 D. to the opposite side of the equation, chang-\\ning the sign with the transposition, and add this amount (2 D.)\\nto the 1.50 D. cyl., which would give 3.50 D. cyl., 165\u00c2\u00b0,.\\nthe axis of the minus cylinder remaining unchanged. The\\ntransposed glass is written thus 2 D. 3.50 D. cyl., 165\u00c2\u00b0.\\nTo convert this same cross-cylinder into a sphero-cylinder\\n(minus sphere with a plus cylinder) give a 1.50 D. sphere\\nin place of the 1.50 D. cyl., then transpose 1.50 D. to the\\nopposite side of the equation, changing the sign in the transpo-\\nsition, and add this amount (1.50 D.) to the 2 D. cyl., which\\nwould give +3.50D. cyl., 75\u00c2\u00b0, the axis of the plus cylinder\\nremaining unchanged. The transposed glass is written thus\\n-1.50D. 4-3.50D. cyL, 75\u00c2\u00b0.\\nIn other words, if we wish to convert a cross-cylinder into a\\nsphero-cylinder (a plus sphere with a minus cylinder), all that\\nit is necessary to do is to give in place of the plus cylinder a\\nplus sphere of equal strength, then add this amount to the\\nstrength of the minus cylinder, leaving its axis unchanged.\\nIf we wish to convert it into a sphero-cylinder (minus sphere\\nwith a plus cjdinder), all that is necessary to do is to give in\\nplace of the minus cylinder a minus sphere of equal strength,\\nand add this same amount to the plus cylinder, leaving its axis\\nunchanged.\\nThis explanation I am sure is plain enough, even to a man\\nwho never heard of algebra.", "height": "4255", "width": "2698", "jp2-path": "refractionofeye00davi_0200.jp2"}, "201": {"fulltext": "TRANSPOSITION OF GLASSES 183\\nA glance at Fig. 77 will show how each of the three\\nglasses,\\n(1) 2 D. cyl., 75\u00c2\u00b0 1.50 D. cyl., 165\u00c2\u00b0;\\n(2) -I-2D. 3.50D. cyl., 165\u00c2\u00b0;\\n(3) 1.50 D. -f- 3.50 D. cyl., 75\u00c2\u00b0;\\nwhich are the cross-cylinder and the sphero-cylinders into\\nwhich it is capable of being converted, can correct the mixed\\nastigmatism in the right eye.\\nWith glass No. 1, the cross-cylinder, the 2 D. cyl., 75\u00c2\u00b0,\\ncorrects the hypermetropia at 165\u00c2\u00b0 (cylinders always acting at\\nright angles to their axes), while the 1.50 D. cyl., 165\u00c2\u00b0, cor-\\nrects the myopia at 75\u00c2\u00b0; thus the eye is rendered emmetropic,\\nor corrected. With glass No. 2, the 2 D. corrects the\\nhypermetropia at 165\u00c2\u00b0 but, since it acts in its whole cir-\\ncumference, it makes the myopia worse to that extent (2D.)\\nin the meridian at 75\u00c2\u00b0, consequently that amount has to be\\nadded to the 1.50 D. cyl., making it 3.50 D. cyh, 165\u00c2\u00b0.\\nWith glass No. 3, the 1.50 D. corrects the myopia in\\nthe meridian at 75\u00c2\u00b0; but here again, since it acts in its entire\\ncircumference, it makes the hypermetropia worse to that extent\\n(1.50 D.) in the meridian at 165\u00c2\u00b0; therefore that amount has\\nto be added to the 2 D. cyl., making it -f 3.50 D. cyl., 75\u00c2\u00b0.\\nAs a rule, when converting cross-cylinders into sphero-\\ncylinders, the weaker cylinder should be converted into the\\nsphere and the same amount added to the stronger cylinder\\nbecause such a combination makes a lighter glass than where\\nthe stronger cylinder is converted into a sphere and the Aveaker\\ncylinder added to it (see example, p. 181, this chapter). How-\\never, in making a choice, some regard must be paid to the\\nopposite eye, if astigmatism is present in that eye, and espe-\\ncially if not of the mixed variety. Several concrete cases will\\nserve to illustrate these points better than mere statements.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0201.jp2"}, "202": {"fulltext": "184 THE REFRACTION OF THE EYE\\nCase LXXII. Mixed astigmatism of large amount^ with\\nthe rule and at off axes; Marked asthenopia^ severe headaches^\\ndizziness Relief ivith glasses. February 27, 1897, Mrs. F.\\nli. P., aged twenty-six years, in good health, has worn glasses\\nat ^imes since a child, but none of the glasses were satis-\\nfacb^ry. When she reads, her eyes and head ache, and if she\\npersists in reading for any considerable length of time, she\\nbecomes dizzy.\\nOphthalmometer. Astigmatism with the rule, 5 D., axis\\n105\u00c2\u00b0 or 15\u00c2\u00b0 right eye; 6 D., axis 75\u00c2\u00b0 or 165\u00c2\u00b0 left\\neye.\\nTest cards a7id trial lenses.\\n2\u00c2\u00a5o y^ 1 D- cyl., 105\u00c2\u00b0 3.50 D. cyl., 15\u00c2\u00b0.\\nL- V. 2V0 f^ W. 1 D. cyl., 75\u00c2\u00b0 4.50 D. cyl., 165\u00c2\u00b0.\\nReads Jaeger No. 1, 5J- to 12 inches.\\nOphthalmoscope. M. 4 D. at 105\u00c2\u00b0 and H. 1 D. at 15\u00c2\u00b0 right\\neye M. 5 D. at 75\u00c2\u00b0 and H. 1 D. at 165\u00c2\u00b0 left eye.\\nSecond test four days later the ophthalmometer gave the\\nsame reading in the right eye, but varied 5\u00c2\u00b0 as to the axis in\\nthe left eye, giving 6 D., axis 70\u00c2\u00b0 or 160\u00c2\u00b0\\nTest cards and trial lenses.\\n2\u00c2\u00a5o 1^ 1-25 D. cyl., 105\u00c2\u00b0 3.25 D. cyl., 15\u00c2\u00b0.\\nL- V. 2V0 U +1 cyl., 70\u00c2\u00b0 4.50 D. cyl., 160\u00c2\u00b0.\\nReads Jaeger No. 1, 5^ to 12 inches.\\nThis last glass was ordered as a sphero-cylinder (plus sphere\\nwith a minus cylinder). Usually, in a case with as large amount\\nof mixed astigmatism as in this case, we prescribe cross-cylinders,\\nbecause it gives a broader field of vision. But in this instance\\nso much of the glass was minus and so little plus that I gave\\nsphero-cylinders. Had the hypermetropic and myopic portions\\nof the astigmatism been nearly or exactly equal, I should have", "height": "4252", "width": "2698", "jp2-path": "refractionofeye00davi_0202.jp2"}, "203": {"fulltext": "ILLUSTRATIVE CASES\\n185\\ngiven cross-cylinders, because they would have given a broader\\nfield of vision than the sphero-cylinders.\\nAgain, in the present case, although I converted the cross-\\ncylinders into a sphero-cylinder, a plus sphere with a minus\\ncylinder, I would not for a moment think to convert them\\ninto a sphero-cylinder with a minus sphere and a plus cyl-\\ninder, because it would have made a very heavy glass, to\\nwit: -3.25 D. -f- 4.50 D. cyL, 105\u00c2\u00b0 right eye; 4.50 D.\\n5.50 D. cyl., 70\u00c2\u00b0 left eye. Although this glass is identically\\nFig. 78.\\nthe same in effect as the cross-cylinder, and the sphero-C5dinder\\nwith *a plus sphere and a minus cylinder, it is not to be con-\\nsidered at all.\\nSometimes in cases where the cross-cylinders and one of the\\nsphero-cylinders into which it can be converted do not differ\\nmuch in weight, as in the cross-cylinder and the sphero-cylin-\\nder (the one with a plus sphere and a minus cylinder) in the\\npresent case, I give a practical test to decide between the fit-\\nness of the two glasses. I first tr}- the cross-cylinders, then\\nthe sphero-cylinders in the trial frame, and find with which the", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0203.jp2"}, "204": {"fulltext": "186 THE REFRACTIOX OF THE EYE\\npatient sees best and most comfortably, and decide accord-\\ningly. Strange as it may seem, they often see considerably\\nbetter with one glass than the other, although theoretically they\\nare supposed to have the same effect.\\nCase LXXIII. Mixed astigmatism tvith the rule; No ambly-\\nopia; Persistent headaches; Relief ivith glasses. September 12,\\n1894, Annie S., aged forty years, in good health, has suffered\\nfrom headaches all of her life. At times the headaches are\\nvery severe in fact, neuralgic in character, and are intensified\\nby any persistent use of the eyes.\\nOphthalmometer. Astigmatism with the rule, 3.50 D., axis\\n100\u00c2\u00b0 or 10\u00c2\u00b0 right eye 3.50 D., axis 80\u00c2\u00b0 or 170\u00c2\u00b0 left\\neye.\\nTest cards and trial lenses.\\nR. Y. J^ 14 w. .T5 D. cyl., 100\u00c2\u00b0 -2D. cyl., 10\u00c2\u00b0.\\nL, y. 2^- :2|_|.^Y. _|..75D. cyl., 80\u00c2\u00b0 -2D. cyh, 170\u00c2\u00b0.\\nWith both eyes at once, distant vision\\nReads Jaeger Xo. 1 from 8 to 18 inches.\\nOphthalmoscope. M. 2 D. at 100\u00c2\u00b0 and H. 1 D. at 10\u00c2\u00b0 right\\neye M. 2 D. at 80\u00c2\u00b0 and H. 1 D. at 170\u00c2\u00b0 left eye.\\nThe above glasses in the form of sphero-cylinders .75 D.\\n2.75 D. cyl., 10\u00c2\u00b0 right eye .75 D. 2.75 D. cyL, 170\u00c2\u00b0\\nleft eye) were prescribed after one test. They gave relief\\nalmost immediatelj^, and have been worn with comfort* ever\\nsince. Of late, however, she feels the need of a stronger glass\\nfor reading, especially at night, and this is to be exjDCcted\\nas she is now forty-three years of age, and her presbj opia\\ndemands it.\\nIt will be seen by this case that even cases of mixed astig-\\nmatism can be fitted correctly, not only without the use of a\\nmydriatic, but at one sitting. Of course, the age of the patient,\\nshe being forty, favored the procedure. In patients under", "height": "4249", "width": "2698", "jp2-path": "refractionofeye00davi_0204.jp2"}, "205": {"fulltext": "ILLUSTRATIVE CASES\\n187\\nforty years of age, in cases of mixed astigmatism, I always\\ngive two, and, in most cases three, tests before giving glasses.\\nThe sphero-cylinder with a plus sphere and a minus cylin-\\nder was more desirable than the sphero-cylinder with a minus\\n170\\nR. E.\\nL. E.\\nFig. 79.\\nsphere and a plus cylinder, because lighter and with the axes\\nof the cylinders horizontally placed, or nearly so, both points\\nin its favor.\\nCase LXXIY. Mixed astigmatism tvith the ride in one eye\\nHypermetropic astigmatism ivith the rule in the other eye; Asthe-\\nnopia Relief with glasses. December 19, 1894, Emily R.,\\niiged thirty-two years, in perfect health, has always suffered\\nwith severe headaches and with pain in the eyes. She has been\\nwearing glasses for the last nine months, but without much\\nrelief from her asthenopic symptoms.\\nOphthalmometer. Astigmatism w^ith the rule, 1 D., axis\\n80\u00c2\u00b0 or 170\u00c2\u00b0 right eye 4.25 D., axis 105\u00c2\u00b0 or 15\u00c2\u00b0 left\\n\u00e2\u0082\u00acye.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0205.jp2"}, "206": {"fulltext": "188 THE EEFRACTIOX OF THE EYE\\nTest cards and trial lenses. The lines in the horizontal me-\\nridian from III to IX are seen plainest in the right eye the\\nlines from IV to X are seen plainest with the left eye until\\n1.25 D. cyl., 105\u00c2\u00b0, is placed before the eye, when all of the\\nlines appear alike, but somewhat blurred. And when the entire\\nplus cylinder, 2.75 D., is placed in front of the eye, the lines\\nfrom I to VII are seen plainest but when 1.50 D. cyl., 15\u00c2\u00b0,\\nis added to the plus cylinder in the frames, all of the lines\\nappear alike and plainly.\\nU \\\\i-^^ .50 D. cyL, 85\u00c2\u00b0.\\nL. V. 2V% f-^ W. 2.75 D. cyl., 105\u00c2\u00b0 1.50 D. cyh 15\u00c2\u00b0..\\nReads Jaeger Xo. 1 from 7 to 18 inches.\\nOphthalmoscope. H. 1 D. right eye H. 2 D. at 15\u00c2\u00b0 and\\nM. 2 D. at 105\u00c2\u00b0 left eye.\\nSecond test the ophthalmometer read the same exactly as\\nat the first test.\\nTest cards and trial lenses.\\nR. V. f f I W. .50 D. cyl., 85\u00c2\u00b0.\\nL. V. 2%: U W. 2.50 D. cyl., 105\u00c2\u00b0 1.50 D. cyL, 15\u00c2\u00b0.\\nThe ophthalmoscope agreed with the first examination-\\nOrdered\\n.50 D. cyl., 85\u00c2\u00b0 right eye\\n-1.50 D.+ l D.cyL, 105\u00c2\u00b0 left eye.\\nI wish to call attention to two points in this case first,\\nthe axis of the cylinder in the right eye varied 5\u00c2\u00b0 from the\\nreading of the ophthalmometer second, I converted the cross-\\ncylinder in the left eye into a sphero-cylinder, a minus\\nsphere with a plus cylinder, and for three reasons (a) to\\nmake the cylinder correspond to the right eye (h) because,\\nin this case, it is a lighter glass than the sphero-cylinder with a\\nplus sphere and a minus cylinder and (c) a cheaper glass.", "height": "4250", "width": "2796", "jp2-path": "refractionofeye00davi_0206.jp2"}, "207": {"fulltext": "ILLUSTRATIVE CASES\\n189\\nAnd this brings me to speak, in a general way, in reference\\nto such cases as the present one, where there is a mixed astig-\\nmatism in one eye and simple or compound astigmatism in the\\nother. In converting the cross-cylinders into sphero-cylinders,\\nsome regard must be had that the character (plus or minus) of\\nthe cylinder in the transposed glass correspond to the cylinder\\nin the opposite eye. Because, as a rule, a plus cylinder on one\\neye and a minus cylinder on the other do not work as well\\nas when both are positive or negative. This point should be\\n105\\nFig. 80.\\nborne in mind, in converting cross-cylinders and, unless by so\\ndoing the weight of the glass is greatly increased, cylinders of\\na like character should be given. Sometimes in such cases it\\nis better to give the cross-cylinder in the mixed astigmatic eye.\\nespecially if the astigmatism is of large amount, rather than\\nconvert it into a sphero-cylinder, either with plus sphere and\\nminus cylinder, or minus sphere and plus cylinder; and, by\\nputting the different combinations in front of the eye for a few\\nmoments, the patient will often make the choice for himself.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0207.jp2"}, "208": {"fulltext": "190 THE REFRACTION OF THE EYE\\nCase LXXV. Mixed astigmatism with tJie 7 ide right eye;\\nHypermetropic astigmatism ivith the ride left eye Marked asthe-\\nnopia Spasm of accommodation Atropine instilled Relief with\\nglasses. February 17, 1894, Pauline J., aged thirty years, is\\nin good general health, but has suffered a great deal from head-\\naches and pains in the eyes. It is almost impossible for her to\\nuse her eyes for close work of any kind, because, of the severe\\nheadaches and discomfort in the eyes when she attempts such\\nwork.\\nOphthalmometer. Astigmatism with the rule, 4.50 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 right eye 1.50 D., axis 90\u00c2\u00b0 or 180\u00c2\u00b0 left\\neye.\\nTest cards and trial lenses. Tiie test with the lines on the\\nclock-dial were thoroughly unsatisfactory, no definite result\\nbeing obtained by them.\\nR. V. J/o- 1^ W. 1 D. 4 D. cyl., 180\u00c2\u00b0.\\nL. V. If: JfW.- ID. cyl., 180\u00c2\u00b0.\\nReads Jaeger No. 1 from 10 to 14 inches.\\nWith the above glasses the patient would see very well for\\na few moments at a time, then everything would fade out,\\nas she expressed it. In fact, this happened several times\\nduring the test when the eyes were being tested separately.\\nIt is unnecessary for me to say that I began the test in each\\neye with my routine method of trying plus glasses first but,\\nas they were refused, minus glasses were next tried, with the\\nabove result.\\nI suspected spasm of accommodation from the way the eyes\\nbehaved during the test, the patient being uncertain of the\\nglasses, and the letters fading out from time to time. The\\nexamination with the ophthalmoscope showed the patient to be\\nmixed astigmatic in the right eye. Retinoscopy confirmed\\nmixed astigmatism in the right eye, but left the diagnosis in", "height": "4249", "width": "2698", "jp2-path": "refractionofeye00davi_0208.jp2"}, "209": {"fulltext": "ILLUSTRATIVE CASES\\n191\\nthe left eye in doubt in fact, indicated myopic astigmatism,\\nwhich, under atropine, proved to be hypermetropic astigma-\\ntism.\\nI might say there were no muscle insufficiencies.\\nAtropine solution (4 gr. to Si) was ordered to be instilled,\\none drop in each eye, three times a day, for four days. Then\\na second test was made.\\nThe ophthalmometer gave the same readings as at the first\\ntest.\\nTest cards and trial\\nR. V. 2V0 f* 2 D. cyl., 90\u00c2\u00b0 -2D. cyl., 180\u00c2\u00b0.\\nL. Y.=^-^: I^W. +25D. +1.50D. cyl., 90\u00c2\u00b0.\\nOphthalmoscope. \u00e2\u0080\u0094B.. 2D. at 180\u00c2\u00b0 and M. 2.50 D. at 90\\nright eye Em. at 90\u00c2\u00b0 and H. 1.50 D. at 180\u00c2\u00b0 left eye.\\n180\\nR. E.\\nL. E.\\nFig. 81.\\nTen days later, when the effects of the atropine had left the\\neyes, a third test was made. The ophthalmometer read uni-", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0209.jp2"}, "210": {"fulltext": "192 THE REFRACTIOX OF THE EYE\\nformly with the two previous tests, and the subjective test,\\nwith the test cards and trial lenses, resulted in the patient\\naccepting the same glasses as when under the influence of atro-\\npine, except that the +.25 D. sphere was not accepted by the\\nleft eye. They were accordingly ordered, a cross-cylinder\\n2 D. cyL, 90\u00c2\u00b0 -2 D. cyl., 180\u00c2\u00b0 right eye, and 1.50 D.\\ncyl., 90\u00c2\u00b0 left eye. The cross-cylinders in the right eye gave a\\nbroader field and more clearly defined the letters than either of\\nthe sphero-cylinders into which it could be converted. How-\\never, had either of the sphero-cylinders been given, it would\\nhave been the minus sphere with plus cylinder, so that the\\ncylinder would have corresponded both in character (plus) and\\nin direction of axis (90\u00c2\u00b0) with the cylinder in the opposite eye.\\nCase LXXVI. Mixed astigmatism luitli the rule left eye;\\nCompound hypermetropic astigmatism luith the rule right eye;\\nAsthenopia; Relief tuith glasses. July 2, 1895, Ida S., aged\\nthirty years, in good health, but has suffered considerably with\\nheadaches since a schoolgirl. She has had numerous glasses,\\nbut none have been comfortable or relieved the headaches.\\nOphthalmometer. Astigmatism with the rule, ID., axis\\n75\u00c2\u00b0+ or 165\u00c2\u00b0- right eye 3 D., axis 120\u00c2\u00b0+ or 30\u00c2\u00b0- left eye.\\nTest cards and trial lenses.\\nR. y. =||_: ffW. +.25D. .50D. cyh, 75\u00c2\u00b0.\\nL. V. =2^^ I^W. +1.25D. cyl., 120\u00c2\u00b0-1.25D.cyL,30\u00c2\u00b0.\\nReads Jaeger No. 1 from 5 to 20 inches.\\nOphthalmoscope. YL. ID. right eye; H. 1.50 D. at 30\u00c2\u00b0\\nand M. 1.50 D. at 120\u00c2\u00b0 left eye.\\nSecond test this resulted in the patient accepting exactly\\nthe same glasses as at the first test, and they were ordered\\n.25 D. .50 D. cyl., 75\u00c2\u00b0 right eye\\n-1.25 D. 2.50 D. cyl., 120\u00c2\u00b0 left eye.", "height": "4265", "width": "2785", "jp2-path": "refractionofeye00davi_0210.jp2"}, "211": {"fulltext": "ILLUSTRATIVE CASES\\n193\\nIn this case, as the mixed astigmatism was not of large\\namount and was equally divided between hypermetropia and\\nmyopia, I converted the cross-cylinder into a sphero-cylinder,\\n120\\nR. E.\\nL. E.\\nFig. 82.\\na minus sphere with a plus cylinder, so that the cylinder would\\ncorrespond in character (plus) with the cylinder in the opposite\\neye.\\nThese glasses have been worn with great comfort.\\nCase LXXVII. Mixed astigmatism tvith the rule left eye;\\nSimple myopic astigmatism ivitli the rule right eye Amblyopia\\nAsthenopia; Relief with glasses. January 9, 1894, George B.,\\naged thirty-five years, in good general health, but has been\\ngreatly troubled with his eyes for many years. He is com-\\npelled to hold reading matter too close to his eyes, and after\\nusing the eyes for close work, vision becomes painful and often\\nheadaches follow.\\nOphthalmometer. Astigmatism with the rule in each eye,\\n3.50 D., axis 105\u00c2\u00b0 or 15\u00c2\u00b0- right eye; 5 D., axis Sd\u00c2\u00b0-{- or\\n175\u00c2\u00b0- left eye.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0211.jp2"}, "212": {"fulltext": "194 THE REFRACTIOX OF THE EYE\\nTest cards and trial lenses.\\nM f^^^- SD. cyl., 10\u00c2\u00b0.\\nL. Y.\\n_2_0\\n100 50\\nI^AV. +2D. cyl., 80\u00c2\u00b0- 2.50 D. cyl.,lW\\nReads Jaeger No. 1 from 6 to 12 inclies.\\nOphthalmoscope. ^L 3.50 D. at 100\u00c2\u00b0 and Em. at 10\u00c2\u00b0 right\\neye M. 3 D. at 80\u00c2\u00b0 and H. 2D. at 170\u00c2\u00b0 left eye.\\nR. E.\\nL. E.\\nFig. 83.\\nSecond test after using an astringent wash for a week, a\\nsecond test was made.\\nOphthalmometer. Astigmatism with the rule, 3.50 D.,\\naxis 100\u00c2\u00b0 or 10\u00c2\u00b0- right eye; 5 D., axis 80\u00c2\u00b0+ or 170\u00c2\u00b0 left eye.\\nThe subjective test resulted in exactly the same glasses\\nbeing accepted as at the first test, and they were ordered\\n-3D. cyl., 10\u00c2\u00b0 right eye\\n2 D. cyl., 80\u00c2\u00b0 2.50 D. cyl., 170\u00c2\u00b0 left eye.\\nHere, again, I did not convert the cross-cylinder into a\\nsphero-cylinder, because the astigmatism was large in amount,.", "height": "4249", "width": "2698", "jp2-path": "refractionofeye00davi_0212.jp2"}, "213": {"fulltext": "ILLUSTRATIVE CASES 195\\nand because by actual trial of both the sphero-cylinders into\\nwhich it could be transposed, the patient saw better with the\\ncross-cylinder. Had I given a sphero-cylinder, it would have\\nbeen a plus sphere with a minus cylinder, in order that the\\ncylinder should correspond in character to the myopic cylinder\\nin the opposite eye.\\nCase LXXVIII. Mixed astigmatism with the rule left eye\\nSimple myopic astigmatism with the rule right eye Asthenopia\\nFitted to glasses without atropine^ although the child was but eight\\nyears old; Relief with glasses. February 7, 1893, William G.,\\naged eight years, is in good health, but has been troubled with\\nheadaches at school. He complains also of not being able to\\nsee the blackboard.\\nOphthalmometer. Astigmatism with the rule, 3.50 D.,\\naxis 105\u00c2\u00b0 or 15\u00c2\u00b0 right eye 2.75 D., 75\u00c2\u00b0 or 165\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nR- V. 2V0 I* W. 3 D. cyl., 15\u00c2\u00b0.\\nL. V. 2V0+ :|^W. 1.25D. cyl., 75\u00c2\u00b0-. 75 D. cyL, 165\u00c2\u00b0.\\nOphthalmoscope. M. 3.50 at 105\u00c2\u00b0 and Em. at 15\u00c2\u00b0 right eye\\nM. 1 D. at 75\u00c2\u00b0 and H. 1.50 D. at 165\u00c2\u00b0 left eye.\\nSecond test after using an astringent wash for a mild\\nconjunctivitis, a second test for glasses was made. The test\\ncorresponded exactly in every way with the first test, and\\nthe glasses were ordered\\n3D. cyl., 15\u00c2\u00b0 right eye\\n1.25 D. 2 D. cyl., 165\u00c2\u00b0 left eye.\\nThese glasses have been worn for more than five years, and\\nwith relief of headaches and other asthenopic symptoms.\\nThe tender age of this patient, eight years, would seem to\\ncall for a mydriatic, especially when it w\\\\as found that mixed\\nastigmatism was present nevertheless, he was fitted without", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0213.jp2"}, "214": {"fulltext": "196\\nTHE REFRACTIOX OF THE EYE\\nit. The axis of the glass corresponded exactly with the axis\\nindicated by the ophthalmometer in each eye but in the left\\neye .75 D. ^Yas deducted from the amount instead of the usual\\n.50 D., as ordinarily in astigmatism with the rule.\\nThe cross-cylinder was converted into a sphero-cylinder, a\\nplus sphere with a minus cylinder, in order that the cylinder\\n165\\nR. E.\\nL. E.\\nFig. 84.\\nmight correspond in axis and character with the simple myopic\\ncylinder of the right eye. This made a slightly heavier glass\\nthan a sphero-cylinder with a minus sphere and a plus cylinder,\\nbut the importance of having both cylinders alike much out-\\nweighed the slight disadvantage in weight.\\nCase LXXIX. 3Iixed astigmatism with the rule right eye;\\nCompound myopic astigmatism with the ride left eye; Constant\\npain in the eyes; Relief tvith glasses. Fehvimry 23, 1892, Ella\\nM., aged twenty-three 3-ears, in good health, came to the clinic\\nof Drs. Roosa and Lewis at the :\\\\Ianhattan Eye and Ear\\nHospital, and was referred to me for treatment. She com-\\nplained of severe pain in the eyes when she attempted close", "height": "4248", "width": "2698", "jp2-path": "refractionofeye00davi_0214.jp2"}, "215": {"fulltext": "ILLUSTRATIVE CASES\\n197\\nwork of any kind, and this has been so since a child. She is\\nthe only member of her family troubled with her eyes.\\nOphthalmometer. Astigmatism with the rule, 3D., axis\\n75\u00c2\u00b0+ or 165\u00c2\u00b0- right eye; 3D., axis 105\u00c2\u00b0+ or 15\u00c2\u00b0- left eye.\\nTest cards and trial lenses.\\nR.V.\\n200\\n20\\nTO\\nW. 1 D. cyl., 75\u00c2\u00b0 1.25 D. cyl., 165^\\nL V\\n200\\n10\\n5D.-2.50D. cyL, 15\u00c2\u00b0.\\nReads Jaeger No. 1 from 6 to 12 inches.\\n165\\nR. E,\\nFig. 85.\\nL. E.\\nOphthalmoscope. \u00e2\u0080\u0094M. 150 D. at 75\u00c2\u00b0 and H. 1.50 D. at 165\u00c2\u00b0\\nright eye M. 7 D. at 105\u00c2\u00b0 and M. 3 D. at 15\u00c2\u00b0 left eye.\\nSecond test two days later the ophthalmometer gave the\\nsame reading as at first.\\nTest cards and trial lenses.\\n2^ I* W. 1.25 D. cyl., 75\u00c2\u00b0 -ID. cyl., 165\u00c2\u00b0.\\nL V -2_iL _2j)_ w _ J. D D PA 1 1\\n-^\u00e2\u0080\u00a2^\u00e2\u0080\u00a2200*100 J- -J C}1., lO\\nThis last glass was ordered, the cross-cylinder in the right\\neye being converted into a sphero-cylinder a plus sphere with", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0215.jp2"}, "216": {"fulltext": "198 THE REFRACTIOX OF THE EYE\\na minus cylinder, in order that the cylinder should correspond\\nin character and axis with the cylinder in the opposite eye.\\nOrdered\\n1.25 D. 2.25 D. cyl., 165\u00c2\u00b0 right eye;\\n4 D. 2 D. cyl., 15\u00c2\u00b0 left eye.\\nThese glasses gave immediate relief from her asthenopic symp-\\ntoms. After a few weeks time she dropped out from under\\nobservation.\\nIn this case, as in the one reported immediately preceding\\nit, the cross-cylinder was converted into a sphero-cylinder, plus\\nsphere with a minus cylinder, rather than into a minus sphere\\nand a plus cylinder. This made a little heavier glass, but the\\ndisadvantage was more than counterbalanced by having the cyl-\\ninders correspond in character and axis. And by actual trial\\nin the frames, before either glass was ordered, the patients pre-\\nferred the plus sphere with a minus cylinder.\\nCase LXXX. Mixed astigmatism with the rule in each eye^\\nwith the axes slanting b\u00c2\u00b0 from the vertical and horizontal meridians\\nin the same direction in each; Asthenopia; Relief ivith glasses.\\nJanuary 21, 1896, D. L. B., in excellent health, but has suffered\\na great deal with his eyes since a child at school. Headaches,\\nblurring of the vision, burning of the eyelids and pains in\\nthe eyes, were some of the symptoms of which he complained.\\nHe has had numerous glasses prescribed, none of which proved\\nsatisfactory.\\nOphthalmometer. Astigmatism with the rule, 3D., axis\\n95\u00c2\u00b0 or 5\u00c2\u00b0 in each eye.\\nTest cards and trial lenses. The lines on the clock-dial\\nwere all seen about equally well with each eye, but indistinctly\\nbefore the test was begun. When the plus cylinder was put\\non, the vertical lines showed the plainest, and when the final\\nfull amount of minus cylinder was added to the plus cylinder,", "height": "4259", "width": "2698", "jp2-path": "refractionofeye00davi_0216.jp2"}, "217": {"fulltext": "ILLUSTRATIVE CASES\\n199\\nthe horizontal lines also came out plainly, thus with the cross-\\ncylinders all of the lines on the clock-dial were brought out\\nplainly and evenly.\\nR. V. 2% 1^ W. -f- 1.50 D. cyl., 95\u00c2\u00b0 1.50 D. cyl., 5\u00c2\u00b0.\\nL. V. 2% M W. 1.25 D. cyL, 95\u00c2\u00b0 1.25 D. cyl., 5\u00c2\u00b0.\\nReads Jaeger No. 1 from 3 to 16 inches.\\nOphthalmoscope. M. 1.50 D. at 95\u00c2\u00b0 and H. 1.50 D. at 5\u00c2\u00b0\\nin each eye.\\nSecond test one day later the ophthalmometer showed the\\nsame reading.\\nTest cards and trial\\nR V -2-0-\\n200\\n20.\\n20\\n1.25D. cyL,5\u00c2\u00b0.\\n1.25 D. cyl., 5\u00c2\u00b0.\\nW. +1.50 D. cyl., 95^\\nL. V. ,2_o_ _2_o_ w. 1.50 D. cyl., 95^\\nA third test confirmed this second, and the glasses were\\nordered as cross-cylinders. Cross-cylinders were prescribed\\nbecause they defined the letters\\nbetter and felt easier to the eyes\\nthan either sphero-cylinder into\\nwhich they could be converted.\\nAfter wearing the glasses con-\\nstantly for a week the doctor\\ngot relief from his asthenopic\\nsymptoms. I have had him\\nunder observation for more than\\ntwo years, and he wears the\\nsame glasses with continued re-\\nlief. It is comparatively a rare\\noccurrence for the axes of an\\nastigmatism in the two eyes to\\nslant in the same direction from\\nthe horizontal and vertical meridians and when it does hap-\\npen, usually, the asthenopia is more marked in such cases than\\nFig. 86.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0217.jp2"}, "218": {"fulltext": "200 THE REFRACTION OF THE EYE\\nin those cases where the axes slant an equal number of degrees\\nin opposite directions from the vertical and horizontal merid-\\nians. For example, say the axis in each eye slants 15\u00c2\u00b0 toward\\nthe temple from the vertical meridian, in which case, in hyper-\\nmetropic astigmatism, the cylinder would be worn at 105\u00c2\u00b0 right\\nej^e, and at 75\u00c2\u00b0 left eye. In the present case both axes stand\\nat 95\u00c2\u00b0, slanting toward the temple in the right eye, and toward\\nthe nose in the left eye, or in the same direction.\\nCase LXXXI. Mixed astigmatism against the rule right\\neye; No corneal astigmatism left eye^ hut the patient accepts a\\nweak cylinder against the rule Patient is very nervous Marked\\nasthenopia; Relief with glasses. June 27, 1894, Mary M., aged\\ntwenty-six years, in only fairly good health, and is very nervous.\\nHer eyes have given her much trouble for the last four years,\\nespecially the right. She finds it almost impossible to use the\\neyes for close work of any kind. Not only do the eyes ache,\\nbut also her head, and often she becomes very nervous and irri-\\ntable. Her mother died of consumption, but her father is still\\nliving and in good health. He wears very strong sphero-cyl-\\ninders, while two brothers and a sister of the patient also wear\\ncylindrical glasses.\\nOphthalmometer. Astigmatism against the rule, 3 D., axis\\n175\u00c2\u00b0 or 85\u00c2\u00b0 right eye. No corneal astigmatism left eye.\\nTest cards and trial\\nR. V. 2^0 M W- 2.50 D. cyL, 175\u00c2\u00b0.\\nL- V. IJ -W. .25 D. cyl., 15\u00c2\u00b0.\\nReads Jaeger No. 1 from 6 to 14 inches.\\nOphthalmoscope. M. 1 D. at 90\u00c2\u00b0 and H. 2 D. at 180\u00c2\u00b0 right\\neye H. 50 D. left eye.\\n1 For the relative position of the axes of astigmatic glasses, see Claiborne,\\nNew York Med. Journal, June 25, and July 2, 1892 Knapp, Trans. Amer.\\nOphthal. Sac, Bd. Vol. VI, p. 308, 1892 and Snellen, Graefe s Arch. Ophthal.,\\nVol. XVI No. 2, p. 200, 1869.", "height": "4254", "width": "2698", "jp2-path": "refractionofeye00davi_0218.jp2"}, "219": {"fulltext": "ILLUSTRATIVE CASES\\n201\\nOn account of a conjunctivitis an astringent wash was\\nordered, and after one week a second test was made. The\\nophthalmometer read the same as at the first test.\\nTest cards and trial lenses.\\nR. V. 2% f^ W. 2.50 D. cyL, 175\u00c2\u00b0 .50 D. cyl., 85\u00c2\u00b0.\\nL. V. |o 10 w. _^ .25 D. cyl., 15\u00c2\u00b0.\\nThe ophthalmoscope agreed essentially with the first ex-\\namination.\\nR. E.\\nFig. 87.\\nL. E.\\nA third test was made, and as it agreed with the second,\\nthis last glass was ordered, a simple cylinder in the left eye,\\n4- .25 D. cyl., 15\u00c2\u00b0, and a sphero-cylinder, .50 D. 3 D. cyl.,\\n175\u00c2\u00b0 right eye. In converting the cross-cylinder into a\\nsphero-cylinder I gave a minus sphere and a plus cylinder.\\nThis made a light glass, and at the same time the cylinder cor-\\nresponded with the cylinder in the opposite eye. A plus\\nsphere and a minus cylinder in this case is not to be thought\\nof, because it would be heavy, and the cylinder would not\\ncorrespond with the cylinder in the opposite eye.\\nIn this case in the right eye the patient accepted all of the", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0219.jp2"}, "220": {"fulltext": "202 THE REFRACTION OF THE EYE\\nastigmatism, no lenticular astigmatism being present. In the\\nleft there was no corneal astigmatism, but the patient accepted\\na weak plus cylinder against the rule.\\nIt took the patient between three and four weeks to become\\naccustomed to the glasses, but after that time she wore them\\nwith comfort and relief from asthenopia. At times she is\\nnervous, but is much relieved in this respect. I saw her from\\ntime to time for a number of months, and the glasses con-\\ntinued to be satisfactory.\\nCase LXXXII. Mixed astigmatism against the rule in each\\neye Spasm of accommodation Marked asthenopia Relief with\\nglasses. August 11, 1894, Jennie F., aged twenty-eight years,\\nin good health, consults me on account of headaches and pains\\nin the eyes. She has had more or less trouble with her eyes\\nsince childhood. There is a well-marked conjunctivitis present.\\nOphthalmometer. Astigmatism against the rule, 3D., axis\\n155\u00c2\u00b0 -f- or 65\u00c2\u00b0- right eye 2 D., axis 175\u00c2\u00b0-}- or 85\u00c2\u00b0- left eye.\\nTest cards and trial lenses.\\n1^ f^ W. 1.50 D. cyl., 155\u00c2\u00b0 1.50 D. cyl., 65\u00c2\u00b0.\\nL-V. f^ :f^W. .75 D. cyl., 175\u00c2\u00b0- .50 D. cyl., 85\u00c2\u00b0.\\nReads Jaeger No. 1 from 6 to 17 inches.\\nOphthalmoscope. \u00e2\u0080\u0094Isi. 1.50 D. at 150\u00c2\u00b0 and H. 1.50 D. at\\n60\u00c2\u00b0 right eye M. 1 D. at 180\u00c2\u00b0 and H. 1 D. at 90\u00c2\u00b0 left eye.\\nDuring the test, especially with the left eye, the patient\\nwould at one time accept a certain glass, then refuse it. Again,\\nthe vision at one moment would be very good, then the next\\nmoment poor. Thus, spasm of accommodation was clearly\\npresent. Examination of the muscles failed to show any\\ninsufficiencies. There was a well-marked conjunctivitis present,\\nand this was treated for ten days, after which a second test\\nwas made.\\nSecond test the ophthalmometer gave the same reading\\nin the right eye as at the first test and the same amount of", "height": "4254", "width": "2698", "jp2-path": "refractionofeye00davi_0220.jp2"}, "221": {"fulltext": "ILLUSTRATIVE CASES\\n203\\nastigmatism in the left eye as at first, but with the axes at\\nexactly 180\u00c2\u00b0 and 90\u00c2\u00b0.\\nTest cards and trial lenses.\\nR. V. 1^ W. 1.50 D. cyl., 155\u00c2\u00b0 1.50 D. cyL, 65\\\\\\nL. V. 1^ f^ W. 1.50 D. cyl., 180\u00c2\u00b0 .50 D. cyL, 90\u00c2\u00b0.\\nOphthalmoscope. Showed about the same condition as at\\nthe first test.\\n65\u00c2\u00b0 90\u00c2\u00b0\\nR. E.\\nL. E.\\nFig.\\nA third test was given which agreed with the second, and\\nthe glasses were ordered as sphero-cylinders, minus spheres\\nwith plus cylinders\\n-1.50 D. +3 D. cyl., 155\u00c2\u00b0 right eye;\\n.50 D. 2 D. cyl., 180\u00c2\u00b0 left eye.\\nIn the left eye this was a lighter glass than a plus sphere\\nwith a minus cylinder, while in the right eye it made no differ-\\nence.\\nThus far, about four years, these glasses have been worn\\nwith comfort.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0221.jp2"}, "222": {"fulltext": "204\\nTHE REFRACTIOISr OF THE EYE\\nCase LXXXIII. Mixed astigmatism of small amount\\nagainst the rule in each eye Presbyopia Asthenopia Blepha-\\nritis Relief of asthenopia and blepharitis ivith glasses. Septem-\\nber 25, 1892, Henry C, aged forty-eight years, in good healtii,\\nhas been troubled with his eyes for five or six years when\\nusing them for close or prolonged work. The eyelids get red\\nalso if he persists in using the eyes, and, at times, headaches\\nfollow.\\nOphthalmometer. Astigmatism against the rule, .50 D.,\\naxis 10\u00c2\u00b0+ or 100\u00c2\u00b0- right eye; .50 D., axis 165\u00c2\u00b0 -f or 75\u00c2\u00b0-\\nleft eye.\\nTest cards and trial\\n=i^ U -50 D. cyl., lO* .25 D. cyL, 100^\\nL. V. 1^ f^ W. .50 D. cyl., 165\u00c2\u00b0 .25 D. cyl., 75\u00c2\u00b0.\\nOphthalmoscope. H. .50 D. in each eye. The myopic\\nastigmatism was too small to estimate. The foci of the two\\nchief meridians, according to the glasses accepted, can be seen\\nfrom the following figure\\nR. E.\\nL. E.\\nFig. 89.", "height": "4262", "width": "2698", "jp2-path": "refractionofeye00davi_0222.jp2"}, "223": {"fulltext": "ILLUSTRATIVE CASES 205\\nTwo days later a second test was made, which corresponded\\nin every particular with the first.\\nIt will be noticed that the myopic portion of the glasses\\naccepted by the patient is very small, only .25 D., and I find\\nin the record of the case in my case-book the following note\\nThe .25 D. cyl. when added to the -f .50 D. cyl. increases\\nthe vision more than a line, or from to |-2-. Usually a\\n.25 D. cylindrical glass does not improve vision so much, but\\nin this case the astigmatism was against the rule and at an off\\naxis (slanting), and that may account for its marked effect in\\nthe improvement of vision.\\nThe patient would not wear glasses for the distance, though\\nthey improved the vision very much. Incidentally it may be\\nremarked here, that many even intelligent people are content\\nwith poor distant vision, and will not wear glasses except for\\nnear work. Some, because they do not wish to be bothered\\nwith two pairs of glasses some refusing to wear glasses on the\\nstreet from vanity, perhaps.\\nOn account of his presbyopia, he being forty-eight years of\\nage, it was necessary to give him reading glasses. I allowed\\n1.75 D. for his presbyopia. After having converted his dis-\\ntance cross-cylinders into sphero-cylinders, .25 D. .75 D.\\ncyl., 10\u00c2\u00b0 right eye, and .25 D. .75 D. cyl., 165\u00c2\u00b0 left eye,\\nit was an easy matter to add the -f- 1.75 D. sphere to them\\nalgebraically, which would give -h 1.50 D. .75 D. cyl., 10\u00c2\u00b0\\nright eye, 1.50 D. -75 D. cyl., 165\u00c2\u00b0 left eye.\\nThe glasses were ordered, and have been worn for five years\\nwithout change. They relieved him of his blepharitis entirely,\\nand made close work comfortable, though for the last few\\nmonths he has felt the want of a stronger glass.\\nA simple increase in the spherical part of his glass will, of\\ncourse, be all that is necessary.\\nThis case naturally brings up the question of transposition\\nof glasses in mixed astigmatism made necessary by presbyopia.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0223.jp2"}, "224": {"fulltext": "206 THE REFRACTIOX OF THE EYE\\nI may say the transposition is made easier if the cross-cylinders\\nare first converted into sphero-cylinders, as in the last case,\\nthen the presbyopic part added to them algebraically. Since\\nthis method of transposition has already been explained at\\nlength, under the lines given to myopia and myopic astig-\\nmatism, I shall not go here into the subject again except to\\ngive one or two examples.\\nIn the last case reported here, for example, the change in\\nthe glasses made necessary by the presence of the 1.75 D. of\\npresbyopia is made quite plain by a glance at Fig. 89 and the\\nfollowing diagram of cross-lines. Those who are in doubt as\\nto the correctness of any combination of glasses they have\\nmade by the abstract algebraic equation, may resort to this\\nmethod of drawing the sections of the two chief meridians\\nof each eye with their foci, together with the simple cross-lines\\ndenoting those meridians, at the ends of which are marked the\\nrefractive power of each meridian in diopters. Then note the\\neffect on the foci that any given amount of presbyopia will cause-\\nFor instance, in Fig. 89, illustrating the last case, right eye,\\nthe meridian at 100\u00c2\u00b0 is hypermetropic by .50 D., and the focus\\nis .50 D. back of the retina .50 D. added to 1.T5 D.\\n-h 2.25 D.); while the meridian at 10\u00c2\u00b0 is myopic by .25 D.\\nwith the focus to that. extent in front of the retina, and the\\npresbyopia of 1.75 D., for reading distance, would put the\\nfocus in this meridian but 1.50 D. back of the retina .25 D.\\nadded to -f 1.75 D. -f- 1.50 D.), that is, the m3-opia of .25 D.\\nneutralizes that amount (.25 D.) of the presbyopia. From this\\nit is quite evident, for reading purposes, the eye has been con-\\nverted into a compound hypermetropic astigmatism, the merid-\\nian at 100\u00c2\u00b0 being 2.25 D. presbyopic, and that at 10\u00c2\u00b0, 1.50 D.\\nIn order to correct this, a -f 1.50 D. sphere, combined with\\n.75 D. cyl., 10\u00c2\u00b0, is necessary. This, in fact, was ordered.\\nLike changes took place in the left eye, as will be seen by look-\\ning at Figs. 89 and 90.", "height": "4257", "width": "2792", "jp2-path": "refractionofeye00davi_0224.jp2"}, "225": {"fulltext": "ILLUSTRATIVE CASES\\n207\\nI have presented these cases of mixed astigmatism in their\\nvarious forms at some length, for the purpose of showing that\\neven these difficult cases may be fitted, in most instances, with-\\nout the aid of a mydriatic. The cases here presented are not\\nselected ones. The indications for the use of a mydriatic in\\nthese cases are exactly the same as in others of refractive error,\\nto wit, lack .of uniformity in tests, spasm of accommodation,\\nand so forth.\\nR. E. L. E.\\nFig. 90. Showing the effect of a presbyopia of 1.75 D. on the near-point in the case\\njust reported. See Fig. 89 for the distance focus.\\nThe amblyopia present in most cases of mixed astigmatism\\nis the one great stumbling-block for many observers, and serves\\nto induce them to use a mydriatic whether there are any other\\nindications for its use or not. In regard to amblyopia, a certain\\namount of it is to be looked for in most cases of astigmatism,\\nespecially if the astigmatism is large in amount consequently,\\nwe should not expect to bring vision up to normal, or nearly\\nso, in all cases. If the patient accepts the same glasses on two\\nor three successive tests, and they correspond Avith the objective\\ntests, we may give the glasses Avithout hesitation.\\nIn order to make myself doubly sure that I am not giving", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0225.jp2"}, "226": {"fulltext": "208 THE KEFRACTION OF THE EYE\\ntoo weak plus, and too strong minus, cylinders in these cases,\\nafter I have tested each eye separately, I then put the glasses\\non as accepted and uncover both eyes. With both eyes uncov-\\nered, I increase the plus cylinder .25 D. in strength, to see if\\nthe vision can be improved by the change, and I also diminish\\nthe minus cylinders .25 D. to find if vision can be improved.\\nAnother point I wish to insist upon is, that the test should\\nbe conducted methodically and quickly, and the patient kept\\nnot over thirty minutes in any one test. Have the patient\\ncome back two, three, or four times, if necessary, but do not\\nworry him for an hour or two at a time in the vain attempt\\nto get perfect vision. Because first, as asserted above, many\\ntimes perfect vision is not to be had, whatever means, mydri-\\natics or what not, are employed to secure it second, if the test\\nis very prolonged, the patient grows tired, becomes confused in\\nhis replies, spasm of accommodation is incited, and the observer\\nhimself gets disgusted and orders a mydriatic, not knowing what\\nelse to do, perhaps. If after two tests, of not more than thirty\\nminutes duration, the tests do not approximately agree, and\\nthere is a tendency to, or an actual, spasm of accommodation,\\nI then order a mydriatic, but not until then.\\nIn all of these cases the routine method of beginning the\\ntest with weak plus glasses and gradually increasing them in\\nstrength until the vision begins to be made worse, and then try-\\ning minus cylinders at right angles to the plus as long as they\\nimprove vision, is followed. The test should never under any\\ncircumstances be begun with minus cylinders, because if it is,\\nthe patient, nine times out of ten, will accept the full amount of\\nthe astigmatism in minus cylinders. While these glasses might\\nbe worn for a few weeks or months even with comparative com-\\nfort, yet after a short time they would have to be changed, as\\nthe patient would gradually relax his accommodation. There-\\nfore, the necessity of avoiding the mistake of beginning the\\ntest incorrectly is apparent.", "height": "4244", "width": "2698", "jp2-path": "refractionofeye00davi_0226.jp2"}, "227": {"fulltext": "CHAPTER VIII\\nlEREGULAR ASTIGMATISM CONICAL CORNEA HYPERBOLIC\\nLENSES CONTACT LENSES ILLUSTRATIVE CASES\\nBefore the days of the perfected ophthalmometer, in no\\nclass of cases did we have more difficulty in fitting glasses,\\neven with tolerable satisfaction, than in those with irregular\\ncurvature of the cornea, due to opacities, conical cornea, and\\nso forth. Thanks to the efforts of Javal and Schiotz, who\\nmade the ophthalmometer a practical office instrument, we now\\nsometimes score our greatest triumphs in just such cases. The\\ndisk of Placido, attached to the 1889 model of the ophthalmom-\\neter, aids greatly in detecting irregularity of surface on the\\ncornea and, for this one reason, if for no other, should not be\\nremoved from the instrument, as suggested and actually done\\nby some of my American confreres. In cases of conical cornea,\\nespecially are the concentric circles on the disk and the disk\\nitself of marked service in giving us the general shape of the\\ncornea and the topography of the cornea at any special point\\non it. Furthermore, by having the patient look at a point a\\ncertain number of degrees from the center of the disk, as\\nmarked on the circles drawn on the disk in conjunction with\\nthe radii drawn from the center of the disk, we can measure\\nthe radius of curvature of the cornea in its two chief meridians\\nat that number of degrees from its center, but on the opposite\\nside from which the patient is looking. For example, if we\\ncause the patient to look directly upward at a point of cross-\\ning of the circle marked 20\u00c2\u00b0, and the radiating line extend-\\ning directly upward, we measure a point on the cornea\\n209", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0227.jp2"}, "228": {"fulltext": "210 THE REFRACTION OF THE EYE\\n20\u00c2\u00b0 below its center. And so for any other point on the\\ncornea.\\nAgain, the circular lines on the disk give us important\\ninformation as to the condition of the surface of the cornea,\\nnot only as to irregular astigmatism, as manifested by irregu-\\nlarity and distortion of these circular lines, but as to the pres-\\nence of regular astigmatism, when present in large amount\\nwith it, as manifested by an elongation of these circles in the\\ndirection of the meridian with the longest radius of curvature.\\nI may say in this place that Reid s ophthalmometer is a most\\nvaluable little instrument in detecting irregular astigmatism\\nand conical cornea of small amount, and for the following\\nreason In Reid s instrument, the two images looked at are\\ntwo circles, or, rather, one circle doubled by means of a prism,\\nand the least irregularity of the surface of the cornea is quickly\\ndetected by these circles becoming irregular in outline. At\\nthe same time, if regular astigmatism is present, it indicates it\\nby the circles becoming elliptical in shape. In conical cornea\\nof moderate amount, if a suitable prism is put in the telescope\\nof the instrument, this instrument is very valuable. The\\nreader is referred to the Appendix of this book for a descrip-\\ntion of the instrument and its use.\\nAgain, in the Javal-Schiotz instrument, the images of the\\nmires themselves are of service in detecting irregular astigma-\\ntism, on the same plan as Wecker s squares, that is, by their\\ndistortion and irregularity of outline when irregular astigma-\\ntism is present. It is also shown when there is no position on\\nthe cornea where the lines dividing them through the center\\ncan be made to form one continuous straight line. However,\\nif regular astigmatism is present in addition to the irregular,\\nthere are two positions on the cornea at which these lines\\nbecome more nearly straight than elsewhere, thus indicating\\nthe axis of the regular astigmatism.\\nSo delicate a test is this distortion of the images of the", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0228.jp2"}, "229": {"fulltext": "IRREGULAR ASTIGMATISM 211\\nmires, that the slightest irregularity of the surface of the cor-\\nnea is detected. This leads to a close inspection of the cornea\\nby oblique illumination, and the detection of minute opacities,\\nwhich otherwise would be overlooked at times.\\nThe ophthalmometer, together with the disk of Placido, is\\nalso of the greatest value in finding the most regular part of a\\ncornea affected with central opacity or leucoma, or, in case of\\nconical cornea, behind which to perform an iridectomy for\\nvisual purposes. It is of the utmost necessity to place the\\niridectomy behind the clearest and most regular portion of the\\ncornea in such cases. Not only is the ophthalmometer of\\nvalue in detecting this best place on the cornea, but it will\\ndetect and measure any regular astigmatism present at such\\nplace. For example, if in a given case we have found the por-\\ntion of the cornea directly inward from the center (right eye)\\nto be the clearest, and have accordingly performed an iridec-\\ntomy for visual purposes, and later wish to fit the eye for\\nglasses. To measure this portion of the cornea, we cause the\\npatient to turn the eye directly outward about 15\u00c2\u00b0 (letting him\\nlook at the point of crossing of the 15\u00c2\u00b0 circle and the hori-\\nzontal radiating line), and ascertain the regular part of the\\nastigmatism. In this way, the fitting of the correct and best\\nglass is greatly facilitated. Indeed, what was at one time a\\nmost tedious, and, in many instances, a hopeless task the\\nfitting of glasses in irregular astigmatism is reduced, by the\\naid of the ophthalmometer and Placido s disk, to a scientific\\nand definite result.\\nSome concrete cases will illustrate the above points.\\nCase LXXXIV. Slight irregular astigmatism due to opac-\\nities of the cornea; Regular astigmatism; Amblyopia Astheno-\\npia. January 4, 1898, Pauline G., aged eleven years, in good\\ngeneral health, came to the clinic of Drs. Lewis and Van Fleet,\\nat the Manhattan Eye and Ear Hospital, and was assigned to\\nane for treatment. The patient s mother says that her child s", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0229.jp2"}, "230": {"fulltext": "212 THE REFRACTION OF THE EYE\\neyes were slightly inflamed when a baby. She has complained\\nof poor and painful vision since she entered school. The patient\\nhas always appeared to be near-sighted.\\nOn looking at this patient s eyes without oblique illumina-\\ntion, no opacities can be seen, and nothing of a peculiar char-\\nacter appears to the observer.\\nOphthalmometer. Regular astigmatism with the rule, 1.50\\nD., axis 90\u00c2\u00b0 or 180\u00c2\u00b0 right eye 1.25 D., axis 75\u00c2\u00b0 or 165\u00c2\u00b0\\nleft eye. Irregular astigmatism in each eye, as made mani-\\nfest by dimness and irregularity of the outlines of the images\\nof the mires, and by the line dividing the mires into halves\\n(guide-lines) not being clear-cut in any position, but dim and\\nwavy in appearance. The concentric circles on the Placido\\ndisk were dim and irregular in outline also.\\nTest cards and trial lenses.\\n^\u00e2\u0080\u00a2^\u00e2\u0080\u00a2=H:f* W. 4-1 D. cyl., 90\u00c2\u00b0.\\nL. V. =|^:f^-W. -I- .75 D. cyl., 75\u00c2\u00b0.\\nReads Jaeger No. 1 from 3 to 15 inches. She has a desire\\nto hold the print too close.\\nOphthalmoscope. Em. at 90\u00c2\u00b0 and H. 1 D. at 180\u00c2\u00b0 right\\neye Em. at 75\u00c2\u00b0 and H. .50 D. at 165\u00c2\u00b0 left eye. Oblique illu-\\nmination of the cornese showed opacities of a diffuse nature in\\neach.\\nSecond test four days after the first test a second one was\\nmade, and as the patient accepted exactly the same glasses as\\nat first, they were ordered. When last seen, about two months\\nafter being fitted, the glasses were giving satisfaction, and the\\npatient was able to pursue her studies with comfort.\\nCase LXXXV. Irregular astigmatism associated with a\\nlarge amount of regular astigmatism folloumig perforating ulcer\\nof the cornea Marked decrease both of the irregular and regular\\nastigmatism^ with attendant increase of vision in one year s time.\\nThis is a most interesting case, because of the changes that", "height": "4257", "width": "2698", "jp2-path": "refractionofeye00davi_0230.jp2"}, "231": {"fulltext": "IRREGULAR ASTIGMATISM 213\\noccurred in the shape of the cornea after the ulcer had healed,\\nwhich were studied by means of the ophthalmometer, and\\nnoted for a long period. I give a brief history of the case\\nMr. D. L., aged thirty-two years, first came under my care\\nSeptember 13, 1893, for treatment for ulcerative keratitis with\\nhypopion, which was due to an injury from a piece of iron from\\na chisel. A large sloughing ulcer covered the lower half of the\\ncornea, extending up almost to the center of the cornea, and\\nthe anterior chamber was half full of pus. With paracentesis,\\natropine, hot water and bandage, the patient recovered in two\\nweeks time, but not without the ulcer perforating. Fortu-\\nnately, the pupil was well dilated before perforation occurred,\\nso there was no prolapse of iris, and the pupil was circular,\\ncentral, and active after the effects of atropine wore off. At\\ntime of discharge of the patient from the hospital he could see\\nthe hand at 2 feet distance only.\\nNovember 4, a little over a month after his discharge from\\nthe hospital, I examined his eye carefully with the ophthal-\\nmometer and with the lenses. I may say at this time that the\\neye was perfectly white, the pupil central and active, and the\\nlower outer quadrant of the cornea had a dense opacity cover-\\ning it, while the lower inner quadrant had a diffuse opacity\\nextending to the level of the lower edge of the pupil. The\\npatient stated that his vision was much improved.\\nOphthalmometer. The right eye had .50 D. astigmatism\\nwith the rule, axis 120\u00c2\u00b0 or 30\u00c2\u00b0 left eye showed marked\\nirregular astigmatism, with a large amount of regular astigma-\\ntism with the rule, 12 D., axis 45\u00c2\u00b0 or 135\u00c2\u00b0\\nTest cards and trial lenses.\\nR. V. not improved.\\nL. V. jV% T^iL W. 9 D. cyl., 135\u00c2\u00bb.\\nOphthalmoscope. H. 1 D. right eye; the fundus in the\\nleft eye is seen indistinctly, the outline of the disk is irregular,", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0231.jp2"}, "232": {"fulltext": "214 THE REFRACTION OF THE EYE\\nand the blood vessels distorted and partly seen that is, a por-\\ntion of a vessel would be seen well one moment and lost the\\nnext, if either the ophthalmoscope or patient s head moved.\\nFebruary 18, 1894, three months later, a second test was\\nmade.\\nOphthalmometer, The astigmatism was the same as at the\\nfirst test in the right eye irregular astigmatism, not so marked\\nas before, and regular astigmatism against the rule, 8.50 D.,\\naxis 15\u00c2\u00b0 or 105\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nR. V. 1^ not improved.\\nL- V. 2% V iVo W. 7.50 D. cyl., 105\u00c2\u00b0.\\nNovember 9, 1894, a little over a year after the first exam-\\nination, the following remarkable improvement was noted\\nOphthalmometer. Test the same in the right eye as before\\nmoderate amount of irregular astigmatism with regular astig-\\nmatism with the rule (as on the first test), 3D., axis 45\u00c2\u00b0 or\\n135\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nR. V. 1^ not improved.\\nL- V. i^A H W. 8 D. cyl., 135\u00c2\u00b0.\\nI had this patient under observation for about fifteen months.\\nThe most interesting feature of the case was the remarkable\\nchange in the character and amount of the astigmatism in the\\nleft eye. Twelve diopters of regular astigmatism with the rule\\nassociated with marked irregular astigmatism changed in a\\nlittle over three months time to 8.50 D. against the rule; and\\nthen in nine months the regular astigmatism diminished to\\n3 D. with the rule., and back to the same axis exactly as at first,\\nand with marked improvement in the irregular astigmatism.\\nWithout the aid of the ophthalmometer, it would have been\\nalmost impossible to note these changes and to make the correct", "height": "4251", "width": "2698", "jp2-path": "refractionofeye00davi_0232.jp2"}, "233": {"fulltext": "IRREGULAR ASTIGMATISM 215\\ntests for vision. With it, it was comparatively easy, and the\\nfact was demonstrated to him, that he had useful vision in the\\nleft eye, should he lose the right. This was naturally a source\\nof great comfort to him.\\nCase LXXXVI. Irregular astigmatism associated with regu-\\nlar astigmatism against the rule right eye Regular astigmatism\\nagainst the rule left eye Asthenopia Relief with glasses. June\\n1, 1894, Mrs. L. T. S., aged forty-one years, is in fairly good\\ngeneral health, has had more or less trouble with her eyes for\\nthe last four years. Twelve years ago she was very much run\\ndown in health and could not use her ej^es for close work for\\nabout two months. She thinks her eyes were weakened when\\na child, from an attack of measles. She has headaches now\\nand pain in the eyes if she sews or reads.\\nOphthalmometer. Irregular astigmatism to a moderate degree\\nwith regular astigmatism against the rule, .50 D., axis 135\u00c2\u00b0\\nor 45\u00c2\u00b0 right eye regular astigmatism against the rule, 3D.,\\naxis 150\u00c2\u00b0 or 60\u00c2\u00b0 left eye.\\nTest cards and trial\\nR. V. f^ 1^ W. 1 D. .50 D. cyl., 135\u00c2\u00b0.\\nL. V. 1^ W. 2.75 D. cyl., 150\u00c2\u00b0.\\nReads Jaeger No. 1 from 7 to 16 inches.\\nOphthalmoscope. -^YL. 2D. at 45\u00c2\u00b0 and H. 1 D. at 135\u00c2\u00b0 right\\neye; H. 3 D. at 60\u00c2\u00b0 and Em. at 150\u00c2\u00b0 left eye. The fundus in\\nthe right eye was made somewhat indistinct by the faint corneal\\nopacities, and the estimation of the error of refraction by the\\nophthalmoscope made doubtful.\\nSecond test two days later, a second test was made in which\\nthe ophthalmometer gave the same readings as at the hrst test.\\nTest cards and trial lenses.\\nR. V. f\u00c2\u00a7 1^ W. -f- 1.25 D. .75 D. cyl., 135\u00c2\u00b0.\\nL. V. II II W. 2.75 D. cyl., 150\u00c2\u00b0.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0233.jp2"}, "234": {"fulltext": "216 THE REFRACTION OF THE EYE\\nThis last glass was ordered, and gave her almost entire relief\\nfrom her headaches.\\nThe ophthalmometer was of especial yalue in this case in\\nascertaining the regular astigmatism present in the right eye,\\nin conjunction with the irregular. Although the vision could\\nnot be brought up to the normal, as in the other eye which had\\nmuch more regular astigmatism, it was greatl}^ improved. The\\namblyopia in the right eye in this case can be accounted for in\\nthe main by the presence of faint opacities in the cornea, as the\\nfundus of the eye was normal. It would have been folly to\\nput atropine in such an eye, as the patient was over forty years\\nof age.\\nCase LXXXVII. Irregular astigmatism in each eye; Large\\namount of regular astigmatism in each eye of the mixed variety\\nSevere asthenopia Vision considerably improved and asthenopia\\nrelieved with the correcting glasses. January 28, 189-i, Bertha\\nG., aged twenty-one years, general health only moderately\\ngood, has had trouble with her eyes since a child, following an\\nattack of measles. Three years ago had an attack of la grippe.,\\nwhich weakened her general strength very much, and since then\\nshe has had recurrent ulcers on the margins of the cornea in\\neach eye.\\nAt present each cornea at its periphery has a row of dense\\nopacities, about three millimeters in diameter, separated by a\\nsmall portion of clear cornea from each other, encircling it\\nentirely. The opacities look very much like the opacities left\\non the cornea at times after an episcleritis. The center of\\neach cornea is clear, but the healing of each ulcer seems to\\nhave put some uneven tension on the cornea, and, as a con-\\nsequence, in the left eye especially, even this clear portion of\\nthe cornea is uneven. This fact is made quite plain b}^ the\\ndistortion of the images of the mires on the ophthalmometer,\\nalso by the circles on Placido s disk.\\nThe patient has been wearing glasses for two years, but\\nthey do not relieve the pain in her eyes and head.", "height": "4257", "width": "2698", "jp2-path": "refractionofeye00davi_0234.jp2"}, "235": {"fulltext": "IRREGULAR ASTIGMATISM 217\\nOphthalmometer. Irregular astigmatism, and regular astig-\\nmatism against the rule, 3D., axis 135\u00c2\u00b0 or 45\u00c2\u00b0 right eye.\\nIrregular astigmatism, and regular astigmatism with the rule,\\n5 D., axis 75\u00c2\u00b0 or 165\u00c2\u00b0 left eye.\\nTest cards and trial\\nI^- M f* W. 2.75 D. cyl., 135\u00c2\u00b0.\\nL. V- f 1^ W. 3.25 D. cyl., 75\u00c2\u00b0 .75 D. cyl., 165\u00c2\u00b0.\\nReads Jaeger No. 1 from 5 to 15 inches.\\nOphthalmoscope. \u00e2\u0080\u0094B.. 2 D. at 45\u00c2\u00b0 and M. 1 D. at 135\u00c2\u00b0 right\\neye H. 3 D. at 165\u00c2\u00b0 and M. 1 D. at 75\u00c2\u00b0 left eye. The fundus\\nof each eye was somewhat hazy and indistinct, and the meas-\\nurement with the ophthalmoscope doubtful.\\nSecond test one day later a second test was made.\\nOphthalmometer. Irregular astigmatism in both. Regular\\nastigmatism against the rule, 2.75 D., axis 140\u00c2\u00b0 or 50\u00c2\u00b0 right\\neye; regular astigmatism with the rule, 4.50 D., axis 75\u00c2\u00b0 or\\n165\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nI^ H f^ W- 2 D. cyl., 140\u00c2\u00b0 .75 D. cyl., 50\u00c2\u00b0.\\nL. V. f^ 1^ W. 4- 3 D. cyl., 75\u00c2\u00b0 .75 D. cyl., 165\u00c2\u00b0.\\nTwo days later a third test was given, which corresponded\\nwith the second, and the glasses were ordered in cross-cylin-\\nders. These glasses were worn constantly, and proved very\\nsatisfactory.\\nThe patient was wearing, when she came under my care,\\n50 D. sphere right eye, and -1- 2 D. cyl., 75\u00c2\u00b0 left eye, which\\nhelped the right eye not in the least and the left e3^e but little.\\nWith the aid of the ophtlialmometer and three tests, without\\natropine, she was fitted with comfortable and much appre-\\nciated glasses. She continued under observation for about six\\nmonths time, and the glasses were still satisfactory at the\\nend of that time.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0235.jp2"}, "236": {"fulltext": "218 THE EEFRACTIOX OF THE EYE\\nCase LXXXVIII. Regular astigmatism with the rule right\\neye Irregular^ astigmatism associated with a large amount of\\nregular astigmatism with the rule of a mixed nature left eye;\\nAsthenopia. February 3, 1893, Katie B., aged sixteen years,\\nin good general health, has been troubled with weak eyes ever\\nsince a child. She had ulcers on the left eye when a child, and\\nhas had calomel dusted into the eye for a long time, but with-\\nout much benefit to vision or clearing up of the opacities.\\nOphthalmometer. Astigmatism with the rule, ID., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 right eye. Irregular astigmatism, also regular\\nastigmatism with the rule, 4.50 D., axis 90\u00c2\u00b0+ or 180\u00c2\u00b0\u00e2\u0080\u0094 left\\neye.\\nTest cards and trial lenses.\\nf^ ff W. .75 D. .25 D. cyL, 90\u00c2\u00b0.\\nL. V. 2V0 1% 1-50 D. cyl., 90\u00c2\u00b0 2 D. cyl., 180^\\nReads Jaeger No. 1 from 4 to 14 inches.\\nOphthalmoscope. \u00e2\u0080\u0094YL. 1.50 D. right eye; M. 2 D. at 90\u00c2\u00b0\\nand H. 2 D. at 180\u00c2\u00b0 left eye. The fundus in the left eye is\\nindistinct and the error of refraction difficult to estimate.\\nA second test resulted in the patient accepting exactly the\\nsame glasses as at the first test, and they were ordered. The\\ndiffuse opacities on the cornea in the left eye prevented much\\nimprovement in the vision, even after the greater part of the\\nastigmatism was corrected, but, as the patient accepted exactly\\nthe same glasses on two successive tests, they were ordered.\\nThese glasses gave relief from her painful vision for two\\nmonths, since which time she has not been under observation.\\nCase LXXXIX. Marked irregular astigmatism^ with a large\\namount of regular astigmatism with the rule right eye Regular\\nastigmatism against the rule left eye Asthenopia only to a limited\\ndegree. February 22, 1896, P. T. Q., aged twenty-six years,\\nin first-class health, has always seen poorly, comes for a pair\\nof glasses. When a child he had an ulcer on the right eye.", "height": "4258", "width": "2698", "jp2-path": "refractionofeye00davi_0236.jp2"}, "237": {"fulltext": "IRREGULAR ASTIGMATISM 219\\nHe does not complain of much pain in the eyes or head, but\\nchiefly of poor vision.\\nOphthalmometer, Irregular astigmatism, also regular as-\\ntigmatism against the rule, 5 D., axis 165\u00c2\u00b0 or 75\u00c2\u00b0 right\\neye regular astigmatism against the rule, 1 D., axis 180\u00c2\u00b0\\nor 90\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nR- V. do iV^ W. 2 D. 5 D. cyl., 75\u00c2\u00b0.\\nL. V. II W. 1.50 D. cyl., 90\u00c2\u00b0.\\nReads Jaegar No. 1 from 5 to 12 inches.\\nOphthalmoscope. M. 3D. at 75\u00c2\u00b0 and 8 D. at 165\u00c2\u00b0 right\\neye Em. at 90\u00c2\u00b0 and M. 2 D. at 180\u00c2\u00b0 left eye. A large\\nopacity occupied the lower half of the right cornea, extending\\nup to a level with the lower edge of the pupil.\\nA second test corresponded with the hrst, and the glasses\\nwere ordered. They were worn with comfort, and with great\\nimprovement in vision.\\nCase XC. Irregular astigmatism very slight., associated\\nwith mixed astigmatism of large amount against the rule left eye\\nUmmetropia right eye. June 3, 1896, C. J. S., aged twenty-\\nseven years, in perfect general health, consulted me on account\\nof poor vision in his left eye. Five years ago he had gonor-\\nrhoeal ophthalmia in the left eye, with perforating ulcer of the\\ncornea. There is a small dense opacity at the lower portion of\\nthe cornea, but with no synechia, however, between the iris and\\ncornea, and the pupil is central, circular, and active. He was\\nfitted to glasses shortly after his recovery from the ophthalmia,\\nwhich have given satisfaction until the last two months. The\\nleft eye has pained him after doing close work of any kind for\\nthe last two months.\\nOphthalmometer. Regular astigmatism with the rule,\\n.50 D., axis 90\u00c2\u00b0 or 180\u00c2\u00b0 right eye slight irregular astio--", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0237.jp2"}, "238": {"fulltext": "220 THE REFRACTIOX OF THE EYE\\nmatism, also regular astigmatism against the rule, 4 D., axis\\n140\u00c2\u00b0 or 50\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nR. V. not improved.\\nL. V. ^Oq 1^ W. 2 D. cyl., 140\u00c2\u00b0 1.50 D. cyl.,50\u00c2\u00b0.\\nReads Jaeger No. 1 from 6 to 21 inches.\\nOphthalmoscope. H. .50 D. right eye; H. 2 D. at 50\u00c2\u00b0\\nand M. 2 D. at 140\u00c2\u00b0 left eye.\\nTwo days later, a second test was made, and the patient\\naccepted exactly the same glass as at the first test. Ordered a\\nplain glass right, and 2 D. cyl., 140\u00c2\u00b0 1.50 D. cyl., 50\u00c2\u00b0\\nleft eye. The glasses gave him complete relief from pain in\\nthe eye.\\nI kept the patient under observation for more than two\\nyears, and at the end of that time he continued to wear the\\nsame glass with comfort.\\nThe irregular astigmatism was but slight in this case, yet\\nenough to be detected by the ophthalmometer, and this could\\nbe done especially when the arc was in the vertical meridian.\\nThe fact, however, of the cornea being perfectly clear at the\\npoint intersected by the visual line, allowed good vision when\\nthe regular part of the astigmatism was corrected. The\\namount of amblyopia that is usually present in such cases was\\nnot present here. I think this can be accounted for by the\\nfact that this astigmatism was acquired, that is, it was pro-\\nduced by a contraction of a scar on the lower half of the\\ncornea. The perceptive part of the eye was not damaged by\\nthe ophthalmia, as proved by the fact that the eye had almost\\nperfect vision when the astigmatism was corrected.\\nCase XCI. Irregular astigmatism associated loith a large\\namount of regular astigmatism tvith the rule in each eye Anti-\\nmetropia; Trichiasis; Asthenopia; Relief with operation and\\nglasses. September 24, 1896, W, B. L., aged twenty-nine years,", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0238.jp2"}, "239": {"fulltext": "IRREGULAR ASTIGMATISM 221\\nin good health, has been troubled with his eyes since fourteen\\nyears of age. This trouble began with inflammation of the\\nlids, followed by ulcers on the eyes, and for the last four years\\nhe has had wild hairs on the left eyelids, which hairs he had\\npulled out from time to time.\\nOn account of the trichiasis and slight entropion of the left\\nupper lid, an entropion operation was performed on this lid\\nbefore glasses were fitted. Two weeks after the operation the\\nfirst test was made.\\nOphthalmometer. Astigmatism with the rule, 6 D., 75\u00c2\u00b0\\nor 165\u00c2\u00b0 with irregular astigmatism right eye astigmatism\\nwith the rule, 6 D., 80\u00c2\u00b0 or 170\u00c2\u00b0 with irregular astig-\\nmatism left eye. Although the irregular astigmatism was made\\nquite manifest by the distortion of the images of the mires,\\nand by the wavy outlines of the line dividing the mires,\\nthere was a large amount of regular astigmatism present which\\ncould be measured with reasonable accuracy.\\nTest cards and trial lenses.\\nI^- 2 A M W 3.50 D. 4.50 D. cyl., 170\u00c2\u00b0.\\nL. V. JJL 1^ W 4.50 D. cyl., 80\u00c2\u00b0.\\nReads Jaeger No. 1 at 8 inches.\\nOphthalmoscope. \u00e2\u0080\u0094M. 10 D. at 90\u00c2\u00b0 and 5 D. at 180\u00c2\u00b0 right\\neye Em. at 90\u00c2\u00b0 and H. 5 D. at 180\u00c2\u00b0 left eye. There are a\\nfew scattering fine opacities on the right cornea on the left\\n\u00e2\u0082\u00acornea, especially at the upper margin, the opacities are more\\nnumerous, giving a faint hazy view to the fundus.\\nFour days later, a second test was made, when the patient\\naccepted the same glasses as at the first test in the left eye,\\nand the same cylinder in the right, but with a half diopter\\nweaker sphere. Ordered\\n4.50 D. cyl., 170\u00c2\u00b0 right eye\\n4.50 D. cyl., 80\u00c2\u00b0 left eye.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0239.jp2"}, "240": {"fulltext": "222 THE REFRACTION OF THE EYE\\nThis patient was kept under observation for fifteen months^\\nand the glasses were at that time still worn with satisfaction\\nand relief from his asthenopic symptoms.\\nConsidering the fact that this was a case of antimetropia,\\nthat a moderate degree of irregular astigmatism was present\\nin each eye, together with a large amount of regular astig-\\nmatism, the result was gratifying. The axis of the cylinder\\nin the right eye did not agree with the reading of the ophthal-\\nmometer by 5\u00c2\u00b0, and 1.50 D. of astigmatism had to be deducted\\nfrom the reading of the instrument in each eye, instead of the\\nusual .50 D. as is usually the case when the astigmatism is with\\nthe rule.\\nCase XCII. Irregular astigmatism; Regular astigmatism;\\nBlepharitis marginalis; Partial relief with glasses. February\\n4, 1896, Mrs. L. G. F., aged twenty-six years, in poor general\\nhealth, has had weak eyes since a small child, she says follow-\\ning an attack of measles. She has never worn glasses. Two\\nyears ago she had recurrent ulcers on the left eye and in the\\nlast few months has had the same trouble again, and her family\\nphysician, Dr. J. T. Wheeler, referred her to me on that\\naccount.\\nOn the right eye, just below the center of the cornea on\\na level with the lower edge of the pupil, is a small dense\\nopacity. On the left cornea near its center are four small\\nfacets and on the lower outer quadrant an oval-shaped opac-\\nity, about 3 mm. long and 2 mm. broad. The edges of the\\nlids are red, and there are some scales on them. She has an\\nherpetic eruption on the hands, and she says when the hands\\nare bad the eyes are better, and vice versa. I may add that she\\nis a very nervous woman.\\nOphthalmometer. Irregular astigmatism slight, with regu-\\nlar astigmatism with the rule, 3 D., axis 105\u00c2\u00b0+ or 15\u00c2\u00b0\u00e2\u0080\u0094 right\\neye irregular astigmatism marked, with regular astigmatism\\nwith the rule, 3D., axis 105\u00c2\u00b0+ or 15\u00c2\u00b0\u00e2\u0080\u0094 left eye.", "height": "4260", "width": "2698", "jp2-path": "refractionofeye00davi_0240.jp2"}, "241": {"fulltext": "IRREGULAR ASTIGMATISM 223\\nTest cards and trial lenses.\\nR- V. jf^ If W. 6 D. 1 D. cyl., 15\u00c2\u00b0.\\nL- V. 2fo M W. 5 D. 2 D. cyl., 15\u00c2\u00b0.\\nReads Jaeger No. 1 at 6|^ inches.\\nOphthalmoscope. M. 7 D. each. Slight posterior staphy-\\nloma in each eye to the temporal side of the disk.\\nA wash of boracic acid was given, also yellow oxide of mer-\\ncury ointment (gr. i to 51) was ordered. After ten days\\ntreatment a second test was given.\\nSecond test the ophthalmometer gave the same reading as\\nbefore.\\nTest cards and trial\\nR. V. 2V0 1^ W. 5 D. 2 D. cyl., 15\u00c2\u00b0.\\nL. V. ^to I* W. 5 D. 2 D. cyl., 15\u00c2\u00b0.\\nReads Jaeger No. 1 at 7 inches.\\nThese last glasses, with .50 D. deducted from the spherical\\nportion, were ordered. They gave the patient much relief\\nfrom the strained feeling in the eyes and made her much more\\ncomfortable. After wearing them for two years I saw her\\nagain. In the last month before the second visit to me, she had\\nhad a small ulcer on the left eye. This reduced the vision\\nsomewhat in that eye, but no glass could improve the vision\\nmore than the one she had on, so no change at all was made in\\nthe glasses. The right eye remained as when I first saw her.\\nHer general condition was somewhat improved, but was still\\nvery poor.\\nCase XCIII. Irregular astigmatism associated with com-\\npou7id myopic astigmatism against the rule left eye; Compound\\nmyopic astigmatism against the rule right eye Asthenopia lie-\\nlief with glasses. November 6, 1897, S. JM. B., aged sixteen\\nyears, in good general health, consults me on account of poor\\nftU", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0241.jp2"}, "242": {"fulltext": "224 THE KEFRACTION OF THE EYE\\nvision and pain in the left eye. She had an ulcer on the left\\neye when eight years of age which perforated, and since then\\nhas seen poorly in that eye. She does not see the blackboard\\nwell at school.\\nShe has worn glasses .50 D. sphere) on each eye for the\\nlast six months, but with little improvement in vision.\\nOphthalmometer. Astigmatism with the rule, .50 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 right eye irregular astigmatism, with regular\\nastigmatism against the rule, 2.50 D., axis 30\u00c2\u00b0 or 120\u00c2\u00b0 left\\neye.\\nTest cards and trial lenses.\\nR. V. |i\\n\u00e2\u0096\u00a0\u00e2\u0096\u00a0u-\\nW.\\n-1.25D.\\nL. V. -ii.\\n:n\\nw.\\n-4 D.\\n2 D. cyl., 120\u00c2\u00b0.\\nReads Jaeger No. 1 from 4 to 15 inches.\\nOphthalmoscope. M. 1 D. right eye M. 4 D. at 120\u00c2\u00b0 and\\n6.50 D. at 30\u00c2\u00b0 left eye. There is an opacity on the left cornea\\nabout 3 mm. in diameter, with the lower pupilary margin of the\\niris incarcerated into it. This opacity is situated halfway be-\\ntween the center of the cornea and its lower margin in the\\nvertical meridian. The fundus in each eye is normal.\\nSecond test three days later, a second test was made.\\nOphthalmometer. Astigmatism with the rule, .25 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 right eye the same reading in the left eye as\\nat the first test.\\nTest cards and trial lenses.\\nI^- M =I^W. .75 D.- .25 D. cyl., 90\u00c2\u00b0.\\nL. V. Jq^o f^ W. 3.50 D. 2 D. cyl., 120\u00c2\u00b0.\\nReads Jaeger No. 1 from 4 to 15 inches.\\nThe ophthalmoscope gave the same result as at the first test.\\nThese last glasses were ordered to be worn constantly.\\nThey gave immediate relief and were worn for a little over a\\nyear with comfort, but at the end of that time, November 26,", "height": "4265", "width": "2698", "jp2-path": "refractionofeye00davi_0242.jp2"}, "243": {"fulltext": "CONICAL CORNEA 225\\n1898, she came again, complaining of some pain in the eyes, and\\nalso of burning and itching of the eyelids. After treating the\\neyelids for a week, I again tested the eyes with the following\\nresult\\nOphthalmometer. Astigmatism with the rule, .25 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 right eye irregular astigmatism and regular\\nastigmatism with the rule, 2.50 D., axis 45\u00c2\u00b0 or 135\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nM I* W. 1 D. .50 D. cyl., 90\u00c2\u00b0.\\nL. V. 2W f^ W. 3.50 D. 1.50 D. cyl., 135\u00c2\u00b0.\\nReads Jaeger No. 1 from 4 to 16 inches.\\nOphthalmoscope. M. 1.50 D. right eye M. 4 D. at 135\u00c2\u00b0 and\\nM. 6 D. at 45\u00c2\u00b0 left eye. Normal fundus in each eye.\\nOn a second test, the patient accepted exactly the same\\nglasses, and they were ordered. For the two months that she\\nhas worn them they have given relief from the pain in the eyes.\\nConical Cornea\\nIn cases of conical cornea, there is always more or less irreg-\\nular astigmatism and, while the ophthalmometer is not capa-\\nble of measuring this astigmatism with exactness, either as to\\nthe amount or the axis, yet with it we are enabled to closely\\napproximate them. Even in extreme cases, when the center of\\nthe cornea is so pointed, or occupied by an opacity, that it is\\nno longer fit for visual purposes, by the help of the ophthalmo-\\nmeter and Placido s disk we are able to select the most suit-\\nable and clearest portion of the cornea outside of the center,\\nnear or in the visual area, which is best for visual purposes. If\\nthis favorable spot is too far from the visual area, and not in\\nfront of the pupil, an iridectomy may be performed behind it,\\nand thus an artificial pupil be made. Not only are Ave able to\\nselect this spot with the oplithalmometer, but, by its aid, we\\ncan measure the astigmatism here, only approximately cor-", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0243.jp2"}, "244": {"fulltext": "226 THE REFRACTION OF THE EYE\\nrect, of course, and we are able often to improve the vision\\nwith cylinders in many of the cases.\\nI am perfectly aware of the fact that the astigmatism is of\\nsuch a high degree in many of these cases of conical cornea, as\\nit is also many times after cataract extraction, that the ophthal-\\nmometer, as now constructed, is only capable of giving the rel-\\native difference of the dioptric power of the two chief meridians\\nof the cornea, and not the absolute or exact measurements in\\nsuch cases. Helmholtz,^ long ago, pointed out the fact that, in\\norder to measure the curvature of the cornea in its various\\nmeridians, one can only use images which are considerably\\nsmaller than the radius of curvature of the cornea, not\\nlarger than one-quarter of the size of the latter. He also\\nshows that one should endeavor to accurately determine these\\nimages to the one-hundredth part of a millimeter if one wishes\\nto calculate accurately the radius of the cornea to the one two-\\nhundredth part of its size.\\nReid,2 in an article on the Scope and Limits of Ophthal-\\nmometry, says, With Javal s instrument, with an image of\\n3 mm., and with the portable ophthalmometer (Reid s), with an\\nimage of 2 mm., it is clear that from the spherical aberration\\nthe absolute size of the radius cannot be determined without\\nreduction, as Leroy has done. And Reid also suggests that\\nin very high degrees of astigmatism it would be better to have\\nan image of only 1.50 mm. in diameter, especially when it\\ncomes to measuring the strongest curved meridian.\\nIn order to have such an image it would be necessary to\\nhave an extra prism for the instrument, which would cause a\\ndoubling of only 1.50 mm., that is, giving an image of 1.50\\nmm. in diameter. Such a prism can be obtained from the\\nmanufacturers.\\nFor all ordinary cases, however, the instruments, as now\\n1 Graefe s Arch. Oph. Vol. I, No. 2, p. 854.\\n2 Annals of Ophthal., St. Louis, Vol. VI. p. 456.", "height": "4248", "width": "2805", "jp2-path": "refractionofeye00davi_0244.jp2"}, "245": {"fulltext": "CONICAL CORN^EA 227\\nconstructed, are accurate enough. In the exceptional cases of\\nvery high degrees of astigmatism, as in conical cornea and\\nsome cases after cataract extraction, the difference in the cur-\\nvature of the two chief meridians, as a rule, can be approxi-\\nmated closely, as can also the position of these two chief\\nmeridians.\\nThe following case of conical cornea will serve to illustrate\\nthe points referred to. See, also, the chapter on Astigmatism\\nafter Cataract Extraction.\\nCase XCIY. Conical cornea^ extreme in the right eye and\\nmarked in the left Irregular astigmatism No improvement with\\nglasses in the rights but the vision was brought from to with\\nglasses in the left eye. December 7, 1898, Miss Nellie F., aged\\nthirty-three years, general health is poor, being subject to sick\\nheadaches, especially severe at the menstrual periods. She had\\ngood sight until thirteen years of age, when she began to men-\\nstruate very profusely, losing great quantities of blood at each\\nperiod, and the sight began to fail rapidly, particularly in the\\nright eye. She became very anaemic, and the vision continued\\nto grow worse for two years, after which time it appeared to re-\\nmain about as it is now. She had considerable pain in the eyes\\nfor the first two years. She cpnsulted an oculist at that time,\\nand also another when twentjr-three years of age. Besides\\ntonics, they prescribed a simple minus 5 D. spherical glass,\\nwhich gave her vision in the left eye, but no improvement\\nin the right.\\nOphthalmometer. Astigmatism against the rule, about 4D.,\\naxis 165\u00c2\u00b0\u00e2\u0080\u0094 or 75\u00c2\u00b0 with irregular astigmation right eye\\nastigmatism against the rule, 8D., axis 30\u00c2\u00b0 -f or 120\u00c2\u00b0\u00e2\u0080\u0094 left eye,\\nwith irregular astigmatism.\\n\u00e2\u0096\u00a0Test cards and trial lenses.\\nR. V. 2^0 not improved.\\nL V -sow _ 10 D cvl 120\u00c2\u00b0", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0245.jp2"}, "246": {"fulltext": "228 THE REFRACTION OF THE EYE\\nReads Jaeger No. 1 from 4 to 10 inches with the left\\neye.\\nOphthalmoscope, Shows an extreme degree of conical\\ncornea right, and a marked degree left eye. The shadow\\ncrescent of conical cornea is beautifully shown in each. In\\nthe right eye the shadow was so pronounced as to suggest an\\nopacity in the lens, but oblique illumination showed a perfectly\\nclear lens, as well as a clear cornea. The ophthalmoscope also\\nshowed the lens to be perfectly clear when the pupil was\\ndilated to permit of a thorough examination. The parallactic\\nmovement was very marked and nicely shown in the left\\nfundus. The fundus in the right eye could be seen but in-\\ndistinctly with either the direct or indirect method the fundus\\nin the left could be seen very well, but only parts of it at\\na time, the blood vessels and background changing with\\neach movement of the eye or of the ophthalmoscope. There\\nwere no opacities in the vitreous, and the fundus appeared\\nnormal.\\nRetinoscopy was totally useless in this case, and even the\\nophthalmoscope was of but small service in the estimation of\\nthe refraction. The subjective test with the clock-dial was\\naltogether unsatisfactory. The ophthalmometer and the sub-\\njective tests with the test case and trial lenses were the only\\nmethods of value in giving the glasses.\\nAfter several tests without a mydriatic and two or three\\nwith a mydriatic, in which all of the tests substantially agreed,\\nI ordered for the right 5 D. sphere (simply to balance the\\nglass in the left eye), and for the left \u00e2\u0080\u009410 D. cyh, 120\u00c2\u00b0, in\\nthe form of a periscopic sphero-cylindric lens. Instead of\\ngiving a 10 D. cyl., 120\u00c2\u00b0, I ordered 5 D. 10 D. cyl.,\\n120\u00c2\u00b0 -f 5 D. That is, a 5 sphere was ground on one side\\nof the glass, and 5 D. sphere and 10 D. cyl., 120\u00c2\u00b0 were\\nground on the other side. In effect, this glass is the same\\nas the 10 D. cyl., 120\u00c2\u00b0.", "height": "4262", "width": "2796", "jp2-path": "refractionofeye00davi_0246.jp2"}, "247": {"fulltext": "CONICAL CORNEA 229\\nThese glasses were for the distance. For readmg, I pre-\\nscribed in the right 5 D. as for the distance and in the left\\neye 3.50 D. cyl., 30\u00c2\u00b0 6.50 D. cyL, 120\u00c2\u00b0, which magnified the\\nprint more than the distance glasses. With these she could\\nread Jaeger No. 1 from four to eight inches better than with\\nthe distance glasses. But she could read the Jaeger No. 1 with\\nher distance glasses, and with the advantage of holding the\\nprint a little farther from the eyes, though it was some smaller.\\nI advised her to use the distance glasses as much as possible.\\nFor a description of periscopic and toric lenses, see the\\nchapter on cataract glasses, where instead of giving a simple\\nbi-convex lens or sphero-cylinder, a toric lens is often given\\nwith great advantage.\\nIn the present case, the first few days after the patient had\\nher glasses they made her very dizzy, and she could not wear\\nthem in the street, but after a few days trial, she was able to\\ngo on the street at will not only this, but she was able to-\\nwear the one pair of glasses, the distance, both for the street\\nand reading. Her headaches were made worse and the attacks\\nmore frequent for the first few weeks after putting on the\\nglasses but her vision was so greatly improved that she per-\\nsisted in the use of the glasses, and now, four months after, the\\nheadaches are much less frequent and less severe. In fact, I\\nsaw her within the week (April 7, 1899), and she tells me she\\nhas not had a single headache for the last month. Her general\\nhealth also has improved.\\nI not only measured this patient s cornea near the center\\n(where the visual lines cut), but 15\u00c2\u00b0 above, below, in, and out.\\nI also located the extreme tip of the cone in each eye, which\\nwas down and out, between 7\u00c2\u00b0 and 8\u00c2\u00b0 from the center of the\\ncornea in each.\\nThe disk of Placido was of value in this case, and I give\\ndrawings of its reflections from the cornea in each eye. The\\nmarked flattening of the circles into irregular ovals is well", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0247.jp2"}, "248": {"fulltext": "230\\nTHE REFRACTIOX OF THE EYE\\n15\u00c2\u00b0 TEMP^\\nshown, the ovals being more drawn out on the side away from\\nthe center of the cornea (see Figs. 91 and 92).\\nThe ophthalmometric readings in this case, as indicating\\nthe radius of curvature and the refractive power of the cornea\\nin its two chief meridians at various points on its surface,\\nwere extremely inter-\\nesting to me, and I give\\nthem below.\\nRight eye the ra-\\ndius of curvature at\\nthe center (where the\\nvisual line intersects) in\\nthe meridian at 75\u00c2\u00b0 was\\n4.38 mm., with a re-\\nfractive power of 76 D.\\nThe meridian at 165\u00c2\u00ae\\nhad a radius of only\\n4.16 mm., with a re-\\nfractive power of 80 D.\\nOf course these re-\\nsults are only approxi-\\nmative, because the spherical aberration was marked and the\\nirregular astigmatism so considerable that the images of the\\nmires were made indistinct and irregular in outline not so\\nindistinct, however, that approximate measurements could not\\nbe made.i For, while the irregular astigmatism was very con-\\nsiderable, it was not near so marked as after many cases of\\ncataract extraction, or as in some cases where corneal opacities\\nare present.\\n1 It should be noted in this connection that a cornea with such a small radius\\nof curvature cannot be measured with the ophthalmometer with the single\\nmovable mire, but only with the ophthalmometer with double movable mires.\\nThis is because with the single movable mire the object cannot be made large\\nenough. For a description of the improvement of double movable mires, see\\nAppendix.\\n15\u00c2\u00b0 BELOW\\nFig. 91 (left eye).", "height": "4257", "width": "2698", "jp2-path": "refractionofeye00davi_0248.jp2"}, "249": {"fulltext": "CONICAL CORNEA\\n231\\nThe radius of curvature of the cornea changed greatly in\\nthe same meridian for instance, 15\u00c2\u00b0 below the center, in the\\nmeridian at 75\u00c2\u00b0, the radius was 5.38 mm., that is, one whole\\nmillimeter longer than at the center, and with a refractive\\npower of only 62 D. as against 76 D. at the center. The radius\\nin the meridian at 165\u00c2\u00b0\\nwas 4.76 mm., with a re-\\nfractive power of 70 D.\\nBy these measure-\\nments it will be seen\\nthat while the radius of\\ncurvature has increased r(g))\\nin length in each me- i5\u00c2\u00b0temp.\\nridian, relatively it in-\\ncreased more rapidly\\nin the meridian at 75\u00c2\u00b0\\nthan it did in the one\\nat 165\u00c2\u00b0, and, therefore,\\nthe astigmatism is much\\nmore marked 15\u00c2\u00b0 below\\nthe center of the cornea than at its center, in fact, just twice\\nas great, being 8 D.\\nLeft eye the left eye could be measured with greater\\nprecision than the right, because the cone was not nearly so\\nmarked as in the right.\\nThe radius of curvature at the center, in the meridian at\\n120\u00c2\u00b0, was 6.20 mm., with a refractive power of 50 D., while\\nthe radius in the meridian at 30\u00c2\u00b0 was 5.96 mm., with a refrac-\\ntive power of 56 D. The mires of the ophthalmometer when\\nturned from the second position, after being approximated, back\\nto the primary position, overlapped eight steps, indicating an\\nastigmatism of 8 D. against the rule. I may say that, in the\\nright eye, a similar discrepancy in the difference in refractive\\npower of tlie two chief meridians, as calculated from the radius\\n15\u00c2\u00b0 BELOW\\nFig. 92 (right eye).", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0249.jp2"}, "250": {"fulltext": "232 THE REFRACTION OF THE EYE\\nof curvature of these meridians, and as indicated by the over-\\nlapping of the mires when turned from the second position\\nback to the primary position, existed. But when the radius of\\ncurvature in one and the same medium changes so rapidly, as\\nin conical cornea, such discrepancy may be expected.\\n15\u00c2\u00b0 below the center (left), the ophthalmometer showed\\nastigmatism against the rule, 5 D., 165\u00c2\u00b0 or 75\u00c2\u00b0\u00e2\u0080\u0094. The\\nradius of curvature in meridian at 75\u00c2\u00b0 Avas 6.18 mm., with a\\nrefractive power of 54 D., while the meridian at 165\u00c2\u00b0 had a\\nradius of 5.75 mm., with a refractive power of 58 D.\\n15\u00c2\u00b0 to the temporal side of the center of the cornea, the\\nophthalmometer showed astigmatism against the rule, 6 D.,\\naxis 150\u00c2\u00b0 or 60\u00c2\u00b0 The radius of curvature in the meridian\\nat 60\u00c2\u00b0 was 6.96 mm., with a refractive power of 18 D., while\\nthe meridian at 150\u00c2\u00b0 had a radius of 6.18 mm., with a refractive\\npower of 54 D.\\n*15\u00c2\u00b0 above the center, the ophthalmometer showed astigma-\\ntism against the rule, 11 D., axis 15\u00c2\u00b0 -h or 105\u00c2\u00b0 The radius\\nof curvature in the meridian at 105\u00c2\u00b0 was 9.33 mm., with a\\nrefractive power of only 36 D., while the radius at 15\u00c2\u00b0 was\\n7.11 mm., with a refractive power of 47 D.\\n15\u00c2\u00b0 to the nasal side of the center, the ophthalmometer\\nshowed astigmatism with the rule, 13 D., axis 75\u00c2\u00b0 or 165\u00c2\u00b0\\nThe radius at 75\u00c2\u00b0 was 7.11 mm., with a refractive power of\\n47 D., while the meridian at 165\u00c2\u00b0 had a radius of 9.88 mm.,\\nwith a refractive power of 34 D.\\nAlthough both of the chief meridians of the left eye at the\\ncenter (the point cut by the visual line) had a radius of curva-\\nture much shorter than the average (7.82 mm.), from which\\nwe would expect some myopia in addition to the astigmatism,\\nnevertheless the patient would not accept any minus sphere,\\nneither would she accept any plus glass, cylinder or sphere,\\neither with or without the mydriatic.\\nI tried the hyperbolic glasses of Raehlmann in this case,", "height": "4254", "width": "2698", "jp2-path": "refractionofeye00davi_0250.jp2"}, "251": {"fulltext": "CONICAL CORNEA 233\\nbut could find none which improved the vision more than the\\nordinary glasses.\\nFor the benefit of those who have not had experience with\\nthe hyperbolic glasses of Raehlmann, I may say that they come\\nin two series, designated A and B respectively, and in\\neach series there are eleven glasses. In the series designated\\nA the axis of the hyperbola is one-third of a millimeter,\\nwhile in the series designated B the axis of the hyperbola is\\ntwo millimeters. In order to fit such glasses, the best plan is\\nto hand the patient each glass in turn in both series and let\\nher move it in different positions in front of the eye until the\\npart of a glass is found which gives the best vision, and this\\nis marked on the glass and sent to the optician to be cut\\nand centered to suit the spectacle frames. I have noticed\\nthat the vision is often much improved by holding the glass\\nobliquely in front of the eye, just as after some cases of\\ncataract extraction where there is a large amount of astigma-\\ntism. These hyperbolic glasses may be obtained through any\\ngood optician. 1\\nThe hyperbolic glasses, besides being costly, are objectionable\\nin another way they narrow the field of vision, that is, the\\npatient in order to see through them has to look directly\\nthrough the optic axis for that reason they are not as suita-^\\nble for the street as for near work.\\nIn some cases of conical cornea the vision is improved by\\nmeans of the stenopaic slit and spherical glasses, but in this\\ncase it was not. While on this topic of conical cornea, it may\\nbe stated also that there is such a thing as a contact glass.\\nThat is, the glasses are ground in the shape of a meniscus, so\\nthat the posterior surface fits the front of the eyeball, somewhat\\nafter the nature of the artificial eje^ while the front surface\\nis ground so as to correct the refractive error. The glasses,\\nI believe, are made in Switzerland. I have known of but one\\n1 Mr. Meyrowitz, of this city, keeps them in stock.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0251.jp2"}, "252": {"fulltext": "234 THE REFRACTION OF THE EYE\\ncase in which they were tried, and in this case they had to be\\ngiven up because of the irritation to the eye. They are worn,\\nof course, just as an artificial eye would be.\\nS. M. Burnett, of Washington, was the first observer in this\\ncountry to make use of the ophthalmometer in measuring\\nconical cornea for the report of his very interesting case, see\\nArchives Oplithal., Vol. XIV, 1885, p. 169.", "height": "4242", "width": "2698", "jp2-path": "refractionofeye00davi_0252.jp2"}, "253": {"fulltext": "CHAPTER IX\\nSTRABISMUS INSUFFICIENCIES OF THE RECTI MUSCLES\\nAMBLYOPIA ILLUSTRATIVE CASES\\nThe symptom, strabismus, convergent and divergent, is so\\nintimately connected with and dependent upon errors of re-\\nfraction, that a brief history of the discovery of this relation\\nby Bonders, and its bearing upon this subject in general, is\\nnot out of place here. In fact, a knowledge of this relation,\\ntogether with a knowledge of the intimate relation between\\nconvergence and accommodation, is of first importance, if a\\ncorrect understanding of this subject is to be had.\\nNot until 1864, when Bonders gave his epoch-making book\\nAccommodation and Refraction of the Eye to the world,\\nwas the condition, or rather symptom, squinting, explained in\\na satisfactory way, and the wdiole subject placed on a scien-\\ntific basis. All observers before Bonders left this subject in\\na hazy condition, even so great a man as Von Graefe failing to\\nrecognize the true cause of strabismus in most cases, to wit,\\nerrors of refraction. Von Graefe attributed the symptom of\\nsquinting chiefly to defective balance, or want of equilibrium\\nof the external muscles of the eyes. He thought that accom-\\nmodation had something to do with it, but he never recognized\\nthe true connection, as cause and effect^ between hypermetropia\\nand convergent strabismus, and myopia and divergent strabis-\\nmus. And while, as Bonders says, many useful hints had been\\ngiven in literature as to the cause of strabismus, yet no one had\\nsought the cause of strabismus (convergent) in hypermetropia.\\nAnd he further adds Indeed, this could scarcely be other-\\nwise. It is only a fcAv years [1864 is the date of Bonders book]\\n235", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0253.jp2"}, "254": {"fulltext": "286 THE REFRACTIOX OF THE EYE\\nsince liypermetropia was properly understood and the forms\\nwliicli are wholly or in great part latent were overlooked until\\nI satisfied myself of their existence, and immediately began to\\nperceive their relation to strabismus. Again, in reference\\nto divergent strabismus, he says On the whole, little sat-\\nisfaction is obtained by consulting the more recent copious\\nliterature on strabismus, with reference to its causes. Stra-\\nbismus clivergens, in particular, is very imperfectly treated of.\\nA distinction of the causes, according to the different forms,\\nis not to be met with, and where the causes of strabismus in\\ngeneral are spoken of, the writers have evidently been filled\\nwith the idea of strabismus convergens.\\nDonders also quotes Yon Graefe to the effect that this\\nobserver believed that insutficiency of the internal recti mus-\\ncles was the cause of divergent strabismtis.\\nIt was Bonders thorough investigation of hypermetropia,\\nmyopia, and errors of refraction in general that revealed to\\nhim the close relation between accommodation and conver-\\ngence, and gave to him the true relation of cause and effect\\nthat existed between hypermetropia and convergent strabismus,\\nand myopia and divergent strabismus.\\nThe method or way in which hypermetropia prodtices con-\\nvergent strabismus is explained as follows In order that a\\npatient with hypermetropia may see well for the distance, he\\nmust use a considerable amount of accommodative effort, and\\nfor near points even more, for, in such cases, the eyeball being\\ntoo short, the rays focus behind the retina, and accommodative\\neffort must be made to bring them up to it, if a clear image\\nis to be obtained. As is now well known, accommodation and\\nconvergence are closely associated, and what calls one into\\npla}^ at the same time and within certain limits, calls the\\nother, hence, when the patient has to use an excessive amount\\n1 Donders. Accommodation and Eefraction of the Eye. p. 306.\\n2 Loc. cit.. p. 415.", "height": "4260", "width": "2698", "jp2-path": "refractionofeye00davi_0254.jp2"}, "255": {"fulltext": "CAUSES OF STRABISMUS 23T\\nof accommodative effort, he at the same time calls into action\\nthe convergence. In doing this, however, sometimes the in-\\nternal recti overact, and one eye, usually the weaker one,\\nshoots inward too far squints, if you please, leaving the\\nbetter eye directed on the object. By suppressing the image\\nin the weaker eye and squinting it inward too far, an exces-\\nsive convergence is obtained, which, in turn, reacts on the\\naccommodation in the good or fixing eye, and assists it by\\nincreasing its action in maintaining a clear image in. that eye.\\nThus single binocular vision for the two eyes is sacrificed in\\norder that the patient can see clearly with one eye.\\nMyopia produces divergent strabismus in the following\\nmanner In looking at distant objects, or even at near\\nobjects, if the myopia is of moderate or large amount, myopes\\nuse no accommodative effort at all for the eye, being too long,\\nis always too strongly refractive (the rays focussing in front of\\nthe retina), and, if accommodative effort is brought into use, it\\nonly makes matters worse. As a consequence, they relax their\\naccommodation to the utmost, and, as convergence is controlled\\nby the same nerve, the third, and acts in unison with\\naccommodation w^ithin certain limits, the convergence in such\\ncases is relaxed at the same time. By this continued relaxa-\\ntion of the convergence, one eye as a rule, the weaker-\\nsighted one turns too far out, that is, squints outward or\\ndiverges, while the better eye fixes the object.\\nWhile Bonders maintained that hypermetropia was the\\ncause of most cases of convergent strabismus, and myopia the\\ncause of most cases of divergent strabismus, yet he did not lose\\nsight of the contributory and auxiliary causes which cooper-\\nated in the production of strabismus.\\nIn Hypermetropia^ the causes are of a twofold nature\\n(1) those whicli diminish the value of binocular vision\\n(2) those which render the convergence easier. Under the\\n1 Loc. cit.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0255.jp2"}, "256": {"fulltext": "238 THE REFRACTION OF THE EYE\\nfirst class of causes lie includes (1) difference in acuteness of\\nvision of the two ejes, due to congenital defect in the retina,\\nor to more marked refractive error in one eye than the other\\n(2) spots on the cornea, or anything that interferes with the\\nacuteness of vision. In the second class of causes he includes\\n(1) faulty structure or innervation of the external muscles of\\nthe eye (2) a large angle alpha^ especially when associated\\nwith a limited range of accommodation.\\nTo paresis of accommodation alone causing convergent\\nstrabismus, he gives but little weight, saying, Diminished\\nenergy, or paresis of accommodation, by itself, is as little liable\\nto produce strabismus as is the range of accommodation con-\\nnected with the increase of years. On the other hand, Javal\\ngives weight to this point, and thinks a temporary paresis of\\naccommodation is a frequent cause of strabismus convergens,\\nand explains it thus, A patient whose accommodation sud-\\ndenly fails is obliged to make a great accommodative effort,\\nwhich is facilitated by an excessive effort of convergence, that\\nis to say, by an attack of strabismus.\\nIn Myopia^ two sets of intiuences tend to produce divergent\\nstrabismus, which Bonders gave under the following headings\\n(1) circumstances which promote movements outwards (2)\\nsuch as deprive binocular vision of its value.\\nUnder the first set of influences he gives (1) too strong\\nexternal recti muscles (2) small or even negative angle alpha^\\ndue to outward displacement of the visual lines (3) long and\\nsuperficially placed eyeballs.\\nAmong the second class of causes he mentions (1) unequal\\nrefraction of the two eyes (2) diminished vision in one eye.\\nTo the first set of causes should be added faulty innerva-\\ntion or under-developed internal recti muscles.\\nBuffon, Miiller, Rente, and others preceded Bonders in con-\\nnecting myopia and divergent strabismus but none of them\\n1 Cited by Roosa, TJie Post- Graduate, December, 1897.", "height": "4257", "width": "2698", "jp2-path": "refractionofeye00davi_0256.jp2"}, "257": {"fulltext": "CAUSES OF STRABISMUS 239\\nhad given the full significance of the relation between conver-\\ngence and accommodation in these cases.\\nI have given Bonders views on strabismus somewhat at\\nlength, because, as I believe, they embrace the correct expla-\\nnation of the method of production of the symptom, strabismus,\\nand the true causes therefor. I may add, but little has been\\nadded to the knowledge of the subject, that is, as to its\\ncauses, other than of an auxiliary nature, since then. As to\\nits treatment, operative and otherwise, much has been done.\\nRoosa, in his recent Treatise on Diseases of the Eye^ gives\\nthe following conclusions in regard to the etiology of stra-\\nbismus convergens, which, as will be seen, agree in the main\\nwith the conclusions of Donders. However, he lays more\\nstress on a higher degree of hypermetropia or hypermetropic\\nastigmatism in one eye than the other than did Donders\\nsufficient, as he says, to produce what may be fairly termed\\nan organic amblyopia, as an etiological factor in the produc-\\ntion of squint. His conclusions are as follows\\nI. Convergent strabismus is generally associated with\\nhypermetropic astigmatism or hypermetropia.\\nII. It is probably caused by congenital anisometropia\\n(unequal refraction) in the majority of cases that is to say,\\nby the inability to secure binocular single vision.\\nIII. In a small contingent it is associated with equal\\nvision in each eye. In such cases the patient fixes with either\\neye alternately. Why the strabismus then occurs is to me\\nuncertain. If it were merely from hypermetropia, why do not\\nnearly all people who are not myopic squint?\\nIV. Opacities of the cornea, or occlusion of the pupil of\\none eye, very much favor the occurrence of squint in eyes of\\nany refraction.\\nV. If strabismus convergens be caused chiefly by ani-\\nsometropia and refractive anomaly, it is not congenital, but\\nit occurs at the age of from two to five years.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0257.jp2"}, "258": {"fulltext": "240 THE REFRACTIOX OF THE EYE\\nVI. If congenital squint or organic disease of the retina\\nexists, suspicion should be excited that it is caused by central\\ndisease.\\nIn regard to the query, in Conclusion III, as to the cause\\nof the squint in hypermetropic eyes of equal acuteness of\\nvision, I may say I believe it to be caused chiefly by a very\\nlarge angle alijlia^ which is usually to be found in such cases.\\nI may say also that I believe a very small or zero angle alplm\\naccounts in a great measure for those anomalous cases of diver-\\ngent strabismus sometimes present in h3^permetropia and that\\na very large positive angle alpha may account for the likewise\\nanom^alous condition of convergent strabismus at times present\\nin myopia. As the angle alpha, as an accessory cause of\\nstrabismus, will be discussed a little farther on, this bare\\nstatement is sufficient here.\\nThe most recent investigations of the anomalies of motility\\nof the eye, in this country, are those by Duane, in a prize essay\\nentitled A New Classification of the Motor Anomalies of\\nthe Eye, based upon Physiological Principles.\\nIn this essay he has made a very careful study of the\\nmotility of the eye, has measured the strength of the ocular\\nmuscles, tested their individual and associated movements, and\\nas a result of his investigations has prepared a new classifica-\\ntion of the motor anomalies of the eye, as he says, based on\\nphysiological principles. I have not adopted the classifica-\\ntion, but would refer my readers to the paper itself, which,\\nI believe, is now to be had in book form.\\nThe conclusions that I have given above, as to the etiology\\nof strabismus, I believe to be a fair expression of the mind of\\nthe profession of to-day. However, there were, and still are,\\nsome who believe that strabismus is due largely to the defects\\nin the muscles themselves, while others believe it to be of cen-\\ntral origin, or the result of imperfect innervation of the differ-\\n1 Annals of Oph. and Otol., October, 1896, January, 1897, and April, 1897.", "height": "4247", "width": "2813", "jp2-path": "refractionofeye00davi_0258.jp2"}, "259": {"fulltext": "V CAUSES OF STRABISMUS 241\\nent muscles of the eye. But Bonders explanation, that in the\\nfixed conditions of the eyeball was to be found the cause of\\nmost cases of strabismus, and that among the fixed conditions\\nhypermetropia and myopia were the most potent factors, has\\nnever been overthrown. In fact, almost all observers since his\\nfirst published views on this subject have concurred in his\\nbelief as to the great influence of hypermetropia and hyperme-\\ntropic astigmatism, and myopia and myopic astigmatism in the\\nproduction of strabismus, convergent and divergent respec-\\ntively. It has been shown by many observers and numerous\\ntables of statistics that hypermetropia or hypermetropic astig-\\nmatism is present in from 75 to 85 per cent of all cases of con-\\nvergent strabismus (some observers giving as high as 98 per\\ncent), while myopia or myopic astigmatism is present in from\\n60 to 75 per cent of all cases of divergent strabismus.\\nBut it is concerning the accessory causes of strabismus that\\nmost dispute and discussion have arisen. Some authorities lay\\ngreat stress on a preexisting disturbance of muscular equi-\\nlibrium. That is, to insufficiencies which finally terminate\\nin actual strabismus. Other authorities have placed much\\nemphasis on the amblyopia (congenital, or acquired from what-\\never cause), usually present in the squinting eye, as the chief\\naccessory cause in the production of the squint. For my own\\npart, I believe that amblyopia plays a more important part as\\na predisposing cause of squint than do insufficiencies of the\\nocular muscles.\\nOf course, all observers agree as to the influence of the\\nlong and superficially placed eyeball in myopia in the produc-\\ntion of divergent strabismus. Here the axis of the eyeball, be-\\ning too long, naturally assumes the direction of the axis of the\\norbit, which, as is well known, is directed forward and outward.\\nAs to the paresis of accommodation causing strabismus\\nconvergens, some authorities give it little Aveight, Avhile\\nothers lay stress on the point. So far as my own observa-", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0259.jp2"}, "260": {"fulltext": "242 THE KEFRACTIOX OF THE EYE\\ntions go, I must sav I have not observed a tendency to con-\\nvergent squint in such cases. I beheve its absence in such\\ncases is to be explained on the same ground upon which\\nDonders explained the absence of convergent strabismus, as\\na rule, in verj high degrees of hypermetropia. He saj s\\nIn such cases the power of accommodation is, even under\\nabnormally increased convergence, not sulhcient to produce\\naccurate images, and such hypermetropics are thus led rather\\nto the practice of forming correct ideas from imperfect retinal\\nimages than of, by a maximum of tension, improving the ret-\\ninal images as much as possible. I have had under my care\\nfor the last four months a young girl, aged thirteen years, with\\nparesis of accommodation from no apparent cause, unless an\\nattack of diphtheria four years previously, which affected the\\nvoice for a short time after, but not the vision, can be given as\\na cause. This patient has no tendency whatever to squint. She\\nhas a hypermetropia 2D., vision which is brought up to\\n1^1 with .75 D. sphere, but she cannot read Jaeger Xo. 1\\ncloser than eight inches with her distance glasses on. Her\\nmother brought her for examination because she held the\\nprint too far from her when reading, as far as an old person,\\nshe said. The patient had no asthenopia whatever, was in\\nperfect health, and had always been, except for the attack of\\ndiphtheria already spoken of.\\nIn several other cases of temporary paresis of accommoda-\\ntion which have come under my observation, I have not noticed\\nany tendency to convergent strabismus. But, as I said above,\\nthese few cases I have seen are not enough to justify me in\\ndrawing positive conclusions therefrom.\\nThe Axgle Alpha\\nThe angle alpha as an accessory cause of strabismus is of\\nmore importance than has, as a rule, been accorded it. The\\n1 Zoc. c?^., p. 301.", "height": "4258", "width": "2805", "jp2-path": "refractionofeye00davi_0260.jp2"}, "261": {"fulltext": "THE ANGLE ALPHA\\n243\\nangle alpha^ that is, the angle between the visual line (^0,\\nFig. 93) and the long axis of the cornea QCD^ Fig. 93) in the\\nhorizontal plane, has considerable influence\\nin the production of strabismus, according\\nto Bonders and Hamer s investigations.\\nAs I wish to convey a clear idea, to the\\nbeginner especially, of the influence of the\\nangle alpha as an etiological factor in the\\nproduction of strabismus, I shall give some\\ndiagrams to help make clear the text on the\\nsubject.\\nThe figure produced to show the angle\\n^Ipha is very diagrammatic. It represents\\nthe right eye as seen from above. XF the\\noptic axis, is the line joining the center of\\nthe cornea and the posterior pole of the eye.\\nCD is the longest axis of the corneal ellip-\\nsoid. In the figure, the apex (C) of the\\ncorneal ellipsoid is represented as being far\\nto the temporal side of the center of the\\ncornea, the spot on the cornea cut by the\\noptic axis, XY, As a matter of fact, these\\npoints almost coincide, and are so treated in\\nactual practice.\\nThis being so, the long axis (CD) of the\\ncorneal ellipsoid and the optic axis (XF\\nwould coincide, and they, also, are considered as one and the\\nsame in actual practice.\\nThe angle alplia^ OKC^ is called positive^ or plus, when the\\nFig. 93. Angle alpha\\n(after Roosa). XT,\\noptic axis H, prin-\\ncipal points com-\\nbined K, nodal\\npoints combined\\nM, center of mo-\\ntion; FO, line of\\nvision MO, line\\nof fixation CDy\\ngreater axis of\\ncorneal ellipsoid\\nOEC, angle alpha\\n(a) OMX, angle\\ngamma (7).\\n1 And, when they are so considered, the angle gamma, formed between\\nthe line of fixation, 031, and the optic axis, XY, varies, that is, increases and\\ndiminishes, in exact proportion with the angle alpha. Moreover, they become\\nnearer equal the farther the object of fixation is removed from the eyes, and^\\nTsvhen the object is at twenty feet or more, they become equal.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0261.jp2"}, "262": {"fulltext": "244\\nTHE REFRACTIOX OF THE EYE\\nA\\nFig. 94. Positive an-\\ngle alpha of twelve\\ndegrees, right eye.\\nfront portion of the long axis of the corneal ellipsoid falls to\\nthe outer or temporal side of the visual line (Fig. 94) and\\nthis is the case in most eyes.\\nIt is said to be negative^ or minus, when the\\nfront portion of the long axis of the corneal\\nellipsoid falls to the inner or nasal side of the\\nvisual line (Fig. 95). .This is comparatively\\nrare, but sometimes occurs in myopia. When\\nthe visual line and the long axis of the corneal\\nellipsoid coincide, it is evident that there can\\nbe no angle alpha at all then it is said to be\\nnil.\\nNow, in the first place, let us see what\\ndetermines the character and the size of the\\nangle alpha; and, in the second place, how\\nthe angle alpha influen-ces the eye to squint.\\nA. The character of the angle alpha is determined by\\n1. The position of the yellow spot^ or macula lutea^ in refer-\\nence to the posterior portion of the optic axis of the eye, that\\nis, the posterior pole of the eye. It should\\nbe remembered that the optic axis and long\\naxis of the corneal ellipsoid are regarded as\\none in practice, as represented in the two last\\nfigures. As long as the macula is situated to\\nthe outer or temporal side of the posterior\\npole of the eye, the angle alpha must be posi-\\ntive for the visual line, FO (Fig. 93), must\\nnecessarily cut the cornea to the inner or\\nnasal side of the optic axis, XT. Further-\\nmore, the further the macula is situated toward\\nthe temporal side of the posterior pole of the\\neye, the larger will the positive angle alp)ha\\nbe. If the macula lutea and the posterior pole of the eye\\nare at the same spot, then the visual line and optic axis must\\nF A\\nFig. 95. Negative\\nangle alpha of six\\ndegrees, right eye.", "height": "4265", "width": "2801", "jp2-path": "refractionofeye00davi_0262.jp2"}, "263": {"fulltext": "THE a:n^gle alpha\\n245\\ncoincide and there is no angle alpha^ or it is nil. If the\\nmacula lies to the inner or nasal side of the posterior pole,\\nthe visual line, FO (Fig. 95), must cut the cornea to the outer\\nor temporal side of the optic axis, and the angle alpha becomes\\nFigs. 96, 97, and 98. Fig. 96, emmetropic eye; Fig. 97, myopic eye; Fig. 98, hy-\\npermetropic eye. nasal side E, temporal side n, optic nerve ga, optic axis\\nll\\\\ visual line d, center of motion K, nodal point. (After Bonders.)\\nnegative and the farther inward from the posterior pole of\\nthe eye the macula is situated, the larger the negative angle\\nalpha will be.\\n2. The length of the eyeball itself influences the size of the\\nangle alpha.\\nIn emmetropia, the angle alpha is positive, and averages\\n5\u00c2\u00b0; in hypermetropia, it is positive, and averages 7.3\u00c2\u00b0 in non-\\nsquinting eyes while, in myopia, it\\nis, as a rule, positive, but may be nil\\nor negative, and averages a little less\\nthan 2\u00c2\u00b0. These are the figures given\\nby Bonders and this author explains\\nthe influence of the length of the eye-\\nball on the size of the angle alpha^\\nas follows\\nThe distance, kg (Fig. 98), from the nodal point to the\\nretina is to be taken into account. It is evident that, if in the\\nhypermetropic eye, wdiere this distance is particularly short,\\nthe yellow spot I is only at the ordinary distance from i^ (a", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0263.jp2"}, "264": {"fulltext": "246\\nTHE REFRACTIOX OF THE EYE\\npoint of the prolonged axis of the cornea), the angle ali^ha^\\nunder which IV and ga intersect one another in becomes\\ngreater. In this, therefore, really lies in part the cause of\\nthe greater value of alpha in hypermetropic eyes but, for the\\nmost part, this greater value must still be explained by the\\nmore external position of the yellow spot.\\nThis position is connected with the arrested development,\\nespecially of the external portion of the hypermetropic eye.\\nA glance at Fig. 97 shows the influence of myopia to diminish\\nthe size of the angle alpha^ by reason of its longer optic axis.\\nB. Hoiv does the angle alpha influence the eye to squint?\\nIt is apparent, if the angle alpha is large, as it often is in\\nhigh degrees of hypermetropia, that the long axes of the cor-\\nnese (and the summits of the\\ncorneae) will be directed in a di-\\nvergent direction when the vis-\\nual lines are parallel (Fig. 99).\\nIf this angle amounts to as\\nmuch as 6\u00c2\u00b0 in a normal eye with\\na corneal radius of curvature of\\neight millimeters (a little above\\nthe average), the linear distance\\non the cornea, from the visual\\nline to the optic axis (summit\\nof the cornea), would be .9 mil-\\nlimeter, or, practically, one mil-\\nlimeter. With an angle alp)ha\\nof 12\u00c2\u00b0, as is sometimes found in\\nhypermetropia of high degree,\\nthis distance would be nearly two whole millimeters. There-\\nfore, with the visual lines of such eyes directed straight ahead\\nand parallel, the summit of each cornea would diverge two mil-\\nlimeters, and the patient would appear to squint outward,\\n1 Loc. cit, p. 249.\\nI\\nFig. 99. Showing an apparent diver-\\ngent squint in hypermetropia of\\nhigh degree, with a large angle\\nalpha (positive).", "height": "4252", "width": "2698", "jp2-path": "refractionofeye00davi_0264.jp2"}, "265": {"fulltext": "THE ANGLE ALPHA 247\\nalthough single binocular vision was present. This apparent\\ndivergent squint is the so-called strabismus incongruus of Mid-\\nler, or the apparent squint of later writers. This apparent\\nsquint appears to be divergent in hypermetropia, and conver-\\ngent in myopia. I have seen, more than once, after tenotomy\\nfor convergent squint in hypermetropia, apparent divergent\\nstrabismus occur and, before the screen test was tried, an\\novereffect from the operation was thought to be present.\\nHowever, with the screen test, both eyes remained fixed when\\ncovered and uncovered, showing the visual lines to be parallel\\nand fixed on the object. Again, I have seen cases, and have\\ncongratulated myself, in fact, on the beautiful result obtained\\nafter tenotomy for convergent squint, where the eyes were\\napparently straight and directed to the same object but, on\\nthe screen test being applied, first one eye and then the other\\nturned outward, showing conclusively that the visual lines\\nstill converged and that the patient did not use the eyes\\ntogether.\\nIncidentally, I may say here, that this screen test is a sim-\\nple and easy way to decide between a true and a false or appar-\\nent strabismus. It consists simply in covering first one eye\\nand then the other with a card, having the patient look at a\\ndistant light, preferably a candle, with the uncovered eye. If\\nthe eye that is covered changes position when uncovered (the\\ncard being placed in front of the other eye), it is a true squint,\\nand shows that the visual lines of the two eyes are not directed\\nto the same point. If the eye turns outward on being uncov-\\nered, it shows a convergent squint to be present, because while\\nbehind the card or screen it turned inward, while the uncov-\\nered eye fixed the object. On the other hand, if the eye turns\\ninward on being uncovered, it shows a divergent squint to be\\npresent, because, while the other eye fixed the object, its visual\\nline diverged, and only turned inward when uncovered and the\\nopposite eye was covered. The same test may be made by", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0265.jp2"}, "266": {"fulltext": "248 THE REFRACTION OF THE EYE\\nhaving the patient look at a near object, as the finger, or a\\npencil.\\nThe large angle alplia^ sometimes present in high degrees\\nof hypermetropia, and giving rise to an apparent divergent\\nstrabismus, may lead to a true convergent strabismus, in the\\nfollowing manner\\nSuch eyes, in order to see binocularly and singly for the\\ndistance, have to direct their visual lines parallelly. But in\\ndoing this they have actually to diverge the centers of the\\ncorneee to do which the external recti may not be quite\\nstrong enough, especially since these patients have to exercise\\naccommodation to see well even for the distance. This act of\\naccommodation in itself stimulates convergence to a certain\\nextent, which latter force would actually oppose the outward\\nmovement of the eye. If, therefore, these eyes have to make\\nan effort, on account of a wide angle alpha^ to keep straight,\\nthat is, their visual lines parallel and directed to the same\\nobject in the distance, when they come to view near objects\\nthe tendency of the visual lines to unduly converge will be\\ngreater still, and the relative insufficiency of the external recti\\nmuscles for the distance may be converted into a true conver-\\ngent strabismus for the near point. Bonders and Hamer were\\nthe first to investigate this point, and to bring statistics to\\nbear showing the influence of a large positive angle alpha in\\nproducing convergent strabismus. These observers measured\\nthe angle alpha in a number of cases of hj permetropia with\\nconvergent strabismus, and the same angle in a number of\\ncases of hypermetropia of about the same degree as those\\nwhich squinted, and found that the angle alpha averaged in\\nsize a little more than one degree larger in the squinting cases\\nthan in the non-squinting ones.\\nDonders says: The result therefore is, that, with equal\\ndegrees of hypermetropia, high values of alpha especially pre-\\ndispose to strabismus convergens. To this I attach more im-", "height": "4232", "width": "2698", "jp2-path": "refractionofeye00davi_0266.jp2"}, "267": {"fulltext": "THE a:n^gle alpha\\n249\\nportance, because it in general proves, that the greater angle\\nalpha^ proper to hypermetropia, is not indifferent in its bearing\\non the connection between hypermetropia and strabismus.\\nMy own experience has led me to the same conclusion as\\nthat formed by Bonders, in regard to the influence of a large\\nangle alpha as an accessory cause in producing convergent\\nstrabismus not only that, but I believe many of the anoma-\\nlous cases of divergent squint in hypermetropia are to be ex-\\nplained by a very small positive angle alpha^ or even with the\\nangle nil, rather than by any muscle defect, either of insertion\\nor structure, or imperfect innervation. My own observations\\non this point, and the cases reported farther on in this chapter,\\nhave led me to this conclusion.\\nOn the same ground of reasoning, the anomalous cases\\nof convergent strabismus in myopia are to be accounted for\\nmost of the time, I believe, by the presence of a large positive\\nangle alpha.\\nA large negative angle alpha\\nhas the same tendency to pro-\\nduce a divergent strabismus in\\nhigh degrees of myopia that\\nthe positive angle alpha has in\\ncausing convergent strabismus\\nin hypermetropia, except that\\nit works in a reverse order.\\nIn such cases, in order to\\nsecure single binocular vision\\nand to have the visual lines di-\\nrected parallelly, the centers or Fig. lOO. Showing the iuriueuoe of a\\nlarge neo-ative aiui le(/( p/n/ in produo-\\nsummits of the COrnese must be eonvergenr sqnint.\\ndirected inward. Now in high\\ndegrees of myopia it is hard to turn the front of the eye inward\\non account of the long eyeball incident to such cases for the\\nliocc/^., p. 301.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0267.jp2"}, "268": {"fulltext": "250 THE REFRACTION OF THE EYE\\noptic axes of these eyes have a tendency to coincide with the\\naxes of the orbits, which latter have an outward direction. If\\nit is difficult, therefore, for these eyes to turn the centers of the\\ncornese relatively too far inward in order to have their visual\\nlines parallel for distant objects, is it not much more difficult\\nfor them, with a wide angle alijlia^ to turn the eyes still farther\\ninward in order to fix near objects with both eyes at the same\\ntime In fact, the wider the negative angle alpha^ the more\\ndifficult it is for the eyes to fix with both eyes at once, hence\\nthe direct influence it exerts in producing a true divergent\\nsquint, though it gives the semblance to the eyes of convergent\\nstrabismus at times.\\nSuch is the influence of the angle aljjlia^ positive and\\nnegative, in causing the eyes to squint. I have considered it\\nsomewhat at length, in order that the beginner might under-\\nstand it, both as to the influence refractive errors have in the\\nproduction of the angle alpha itself, making it positive or\\nnegative, and smaller or greater, as the case may be and the\\nsecondary influence the angle has in causing a true squint.\\nFurthermore, it will teach him to observe between true and\\napparent or false squint.\\nBut it is not merely to show the influence of the angle alpha\\nin the production of squint that I have gone rather fully into\\nits exposition here, but also to show how the angle alpha may\\ninfluence the reading of the ophthalmometer and the fitting\\nof glasses. In an article in the New Yoi^k Medical Journal^\\nFebruary, 1895, I have explained this influence.\\nThose who are only fairly well acquainted vtdth the use of\\nthe ophthalmometer are aware of the fact that the whole of the\\ncornea is not measured in an ordinary examination, but only\\na very small portion of it a space of only 2 J to 3 millimeters\\nin diameter. Furthermore, the center of this space does not\\ncoincide with the center of the cornea, except when the visual\\n1 See also Appendix of this book.", "height": "4249", "width": "2698", "jp2-path": "refractionofeye00davi_0268.jp2"}, "269": {"fulltext": "THE ANGLE ALPHA 251\\nline coincides with the long axis of the cornea,^ but with that\\npoint on the cornea intersected by the visual line, which point\\nis usually a little to the nasal side of the center of the cornea\\n(2\u00c2\u00b0 to 5\u00c2\u00b0), and, as a rule, on a horizontal line with it. How-\\never, on rare occasions this point is on the temporal side of the\\ncenter of the cornea, that is, when there is a negative angle\\nalpha.\\nWhen this angle is large, especially when there is a high\\ndegree of astigmatism, and associated with a large amount of\\nhypermetropia or myopia, the readings of the ophthalmometer\\ndo not correspond so closely with the subjective tests as in the\\ncases with lower amounts of astigmatism and with a small or\\naverage angle alpha. For example, in an eye with a radius\\nof curvature of 8 mm., an angle alpha of 6\u00c2\u00b0 is 0.9 mm., or prac-\\ntically 1 mm., and with angle alpha of 12\u00c2\u00b0 it would, of course,\\nbe 2 mm. (see Fig. 94). In such case, therefore, the point on\\nthe cornea measured by the ophthalmometer would be 2 mm.\\ndistant from the center of the cornea. Now the two chief radii\\nof curvature at this point may be considerably different from\\nthe radii of curvature at the apex or center of the cornea. To\\nsimplify matters, we will assume that the radius of curvature,\\nchanges in but one of the chief meridians, that of the vertical,\\nwhile it remains unchanged in the horizontal.\\nLet the radius of curvature of the horizontal meridian at\\nthe center of the cornea be 8 mm., and that of the vertical\\nmeridian 7.61 mm. According to Javal s formula,\\nD 1000i^^\u00e2\u0080\u0094\\nT\\nthe astigmatism at the center of the cornea in such a case is\\n2 D. Say, however, at a distance of 2 mm. from the center of\\nthe cornea the radius of curvature of the vertical meridian\\nbecomes slightly shorter, changing from 7.61 to 7.81 mm.\\n1 The long- axis of the cornea and the optic axis are considered as one and\\nthe same in practice.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0269.jp2"}, "270": {"fulltext": "252 THE REFRACTION OF THE EYE\\nin length, while the radius of curvature of tlie horizontal\\nmeridian remains the same as at the center of the cornea.\\nAccording to the formula given above, the astigmatism at this\\npoint would be 4 D. The difference in the amount of the\\nastigmatism at the two points would be clearly two whole diop-\\nters. Of course, this is a much exaggerated case, but it serves\\nto illustrate how a large angle alpha may affect the readings of\\nthe ophthalmometer and how the astigmatism at the center of\\nthe cornea may vary from that at the point on the cornea\\nintersected by the visual line.\\nAs to the mooted question of the amblyopia which is\\nusually present in strabismus cases, whether tliis amblyopia\\nis congenital and causes the squint, or the squint causes the\\namblyopia from non-use of the eye (^amblyopia ex anopsia^ I\\nshall have little to say, not having any new evidence to offer\\nfor either side.\\nMany authorities believe that the amblyopia present in\\nmost cases of strabismus is usually congenital, that is, organic^\\ndue to disease, and is the chief cause of the squint but that it\\nis in a few cases acquired, functional^ and is brought about in\\nsuch cases by the non-use of the squinting eye. The mere\\nfact, however, that the great majority of squints (convergent)\\ndevelop between the ages of two and seven years, makes it\\nquite evident that on account of the youth of the patient, it is\\nalmost impossible to decide if the patient has amblyopia before\\nsquinting, even if tests were attempted. Those holding this\\nview, as they cannot depend on such examinations to decide\\nthe point, must judge by the result of the operation, the cor-\\nrection of the error of refraction and enforced use of the weak\\neye, to determine if the amblyopia is organic or functional.\\nIf organic, they say the amblyopia is not improved, while, if\\nfunctional, it may be. And the fact, well established by\\nexperience, that the vision in the squinting eye, in the\\ngreat majority of cases, is not and cannot by any means", "height": "4257", "width": "2782", "jp2-path": "refractionofeye00davi_0270.jp2"}, "271": {"fulltext": "AMBLYOPIA m STRABISMUS 253\\nwhatever and however long persisted in be improved but\\nvery little, seems to lend weight to the contention that the\\namblyopia in nearly all these cases is organic and not func-\\ntional. For, if not organic, they ask, why is not the vision\\nimproved when the eye is put in condition for seeing?\\nEyes with cataracts on them for years see after the cataracts\\nare removed. Why is there not amblyopia in these cases\\nfrom non-use, if non-use can cause an amblyopia, incapable of\\nbut slight or no improvement\\nJaval, of Paris, has, by the use of the stereoscope, by the\\nenforced use of the weak eye to the exclusion of the good one\\nfor months at a time, etc., been able to secure improvement in\\nvision in some of these apparently organic cases. But the\\nmajority of observers do not make such strenuous efforts, or\\npersist in them for as long, as does Javal. After the im-\\nprovement obtained in the first few weeks, the vision is\\nrarely further improved and, even though by the use of the\\nstereoscope, and so forth, binocular single vision is restored,\\nunless continued practice of the stereoscope is persisted in, this\\nis lost again in many cases. Of course, where we have an\\nintelligent patient, with the inclination and the leisure to keep\\nup these exercises, it is entirely justifiable and should be en-\\ncouraged.\\nPersonally, I am of the opinion that the amblyopia in stra-\\nbismus cases is usually functional, and due to the squint,\\nthough at one time I held the opposite view. That strabismus\\nmay cause, or, at least, be coincident with, amblyopia, there can\\nbe no doubt, as a few well-authenticated cases show.\\nDr. Walter B. Johnson, of Paterson, N. J., has reported\\nthe most remarkable case of this kind, as follows\\n1 Fuchs claims that the non-use of a cataractous eye does not make it\\namblyopic, simply because the retina is developed and practiced before the\\ncataract (senile) is formed but that in congenital cataract and squint cases the\\nretina in the affected eye is often incompletely developed, hence amblyopia.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0271.jp2"}, "272": {"fulltext": "254 THE REFRACTIOX OF THE EYE\\nT. McK., aged nineteen, June, 1887, file forger, has been\\ncross-eyed since three years of age, and states that during his\\nrecollection he had been unable with the left, squinting eye, to\\ndiscern any object and define its character. He constantly\\nfixes with the right eye.^\\nR. V. ll L. V. fingers at 6 inches. Fundus normal\\nin each. June 13, the right eye was injured so badly with a\\nfile that it was enucleated the same day. June 18, L. V.\\nfingers 3 inches. Under continued practice with test letters\\nand reading cards, by July 1, L. V |4, and reads Jaeger Xo.\\n1 at 12 inches. The false fixation which he had was overcome.\\nThree years later. V.\\nThe peculiarities in the case. Dr. Johnson says. are the\\nlength of time the amblyopia had existed (sixteen years), the\\nreturn of perfect vision, and the shortness of time required for\\nthe vision to become normal.\\nA second remarkable case of this nature is reported by Dr.\\nSt. John Roosa.\\nRoosa s patient was a child aged seven years, from a squint-\\ning family, who had no squint at time of examination, but\\nwas said to squint at times. R. and L. V. |-J H. 5 D. She\\naccepted and wore 1: D. In four years after, this child\\ncame with a fixed squint, by preference in the right eye, and\\nthe vision in that eye was reduced to while the left, the\\nnon-squinting eye, remained at |-J. The examinations, first\\nand last, were made with great exactness, by competent men^\\nthe late Dr. Edward T. Ely and my present associate. Dr.\\nJ. B. Emerson, and I have no doubt of the truth of the\\nobservation. I advised an operation, but the case disappeared\\nbefore I had the opportunity of making the crucial test of par-\\nalyzing the accommodation, and securing the best vision pos-\\nsible with glasses under such paralysis.\\n1 Trans. Amer. Oj h. Soc. July. 18P3, Vol. VI, p. 551.\\n2 Treatise on Diseases of the Eye. p. 54y.", "height": "4257", "width": "2698", "jp2-path": "refractionofeye00davi_0272.jp2"}, "273": {"fulltext": "INSUFFICIENCIES OF THE OCULAR MUSCLES 255\\nI may say, Roosa formerly held to the view that the ambly-\\nopia was congenital, but does so no longer.\\nSamuel D. Risley, of Philadelphia, reports a case of alter-\\nnating amblyopia occurring in alternating convergent squint,\\nwith recovery in each eye. He also reports two other cases\\nof amblyopia that became greatly improved. Harlan, Knapp,\\nHolt, Javal, are others who have reported such cases.\\nCertainly these cases furnish positive evidence, and are not\\nevidence of the negative nature, which the congenital cases\\nmust necessarily be. For this reason they are very convincing.^\\nInsufficiencies of the Ocular Muscles\\nBefore proceeding to give illustrative cases of strabismus, I\\nwish to speak briefly of insufficiencies of the ocular muscles,\\nespecially in their relation to refractive errors.\\nTo Graefe belongs the honor of clearly distinguishing\\nbetween muscular insufficiency and strabismus, and we are\\ndeeply indebted to him for his classical investigations in this\\nfield of work. Although some of his methods of testing the\\nmuscles were at fault, and have since been given up, yet his\\ninvestigations put the subject on a scientific basis, and pointed\\nthe way for later investigators.\\nWe are also greatly indebted to Alfred Graefe for his con-\\ntributions on the subject of strabismus and muscular insuffi-\\nciencies. It was he who emphasized the fact that before\\ntesting for insufficiencies of the ocular muscles we should first\\ncorrect any refractive errors that might be, and often are,\\npresent in such cases, a point, by the way, of prime impor-\\ntance. Other distinguished investigators have added to the\\nsubject, but the name of the two Graefes stands out conspicu-\\nously.\\n1 For a very valuable paper on this subject, see Annals of Ophthalmolocfi/\\nand Otology, April, 1895, An Argument for xVmblyopia ex Anopsia in Con-\\nvergent Strabismus, by W. Franklin Coleman.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0273.jp2"}, "274": {"fulltext": "256 THE REFRACTIOX OF THE EYE\\nThe insufficiency of a muscle may rightly be called a latent\\nstrabismus. It may be of the slightest amount or very marked,\\nand may develop into a true or manifest squint, especiall} when\\nassociated with large errors of refraction, or when prisms are\\nprescribed and gradually increased in strength, thereby stimu-\\nlating the stronger, antagonistic muscle to even greater exertion.\\nMuscular insufficiency of large, or even of moderate, degree,\\nthat is, of amount sufficient to give rise to asthenopic symp-\\ntoms or to call for operative interference, not associated with\\ntroublesome refractive error or a general debility, is so rare as\\nhardly to call for consideration at all, except for the satisfac-\\ntion obtained in making a complete examination in every case.\\nAs for the insufficiencies that are associated with refractive\\nerrors, we know that these, as a rule, are relieved by simply\\ncorrecting the refractive error. In the few cases that are not\\nrelieved by glasses alone, tonics, rest, and outdoor exercise, by\\nthose who can take it, will generally accomplish the desired\\nresult.\\nIn the very limited number of cases that are not relieved\\nby the above methods, and where the muscular insufficiency is\\nso great as at times to cause diplopia and great annoyance, oper-\\native interference is called for in the form of a tenotomy a\\ncomplete tenotomy, and not the so-called graduated tenotomy.\\nHowever, the cases that call for operative procedure are rare,\\nas nearly every case of muscular insufficiency can be relieved\\nwith glasses, rest, outdoor exercise, and tonics. And I agree\\nwith Roosa when he says, So long as there is no deformity,\\nso long as the patient has no double vision, and can see to read\\nwell with the eyes, any operative interference, in m} judgment,\\nis utterly unwise, and founded on a false conception of the\\ntrue condition of things. In other words, I believe that no\\noperation is justifiable in these cases until the insufficiency\\n(which is a latent squint) develops into an actual manifest\\ni The Fast Graduate, December, 1897, p. 725.", "height": "4249", "width": "2698", "jp2-path": "refractionofeye00davi_0274.jp2"}, "275": {"fulltext": "INSUFFICIENCIES OF THE OCULAR MUSCLES 257\\nsquint, periodic in nature, but, nevertheless, a true squint.\\nOperative measures, even then, should not be undertaken,\\nexcept in adults (sixteen years of age or over), and until all\\nother means have failed.\\nThere are a few cases of muscular insufficiency that are not\\nrelieved by any procedure whatever glasses, tonics, rest, op-\\nerations, or what not. These cases, Knapp says,^ are benefited\\nby the effects of age. He said he had been told this by Graefe,\\nwhen working in his clinic, and that it had been borne out in\\nhis experience. In some way, increasing age seemed to har-\\nmonize the maladjustment between convergence and accommo-\\ndation which maladjustment, probably, was at the bottom of\\nmost of these cases. He thought the idea advanced by Dr.\\nS. M. Payne, in one of his papers on this subject, of correcting\\nthe refractive error almost fully in those cases with excessive\\nconvergence, to be the correct one, and one giving more re-\\nlief than any other procedure.\\nPerhaps it is not out of place here to give the meaning of\\nthe terms adduction, abduction, sursumduction the methods\\nof testing for insufficiencies of the ocular muscles, and what\\nmay be considered an insufficiency of action in a muscle as\\nmeasured by prisms, the tropometer (Stevens), or otherwise\\nand the ratio or relative strength of a muscle as compared to\\nthe other muscles.\\nAdduction means, literally, to turn to or toward; and, as\\nregards the median plane of the head, this would be inward\\nturning of the eyes. It is accomplished chiefly by the inter-\\nnal recti muscles, assisted by the superior and inferior recti\\nmuscles.\\nAbduction means, literally, to turn outward. It is accom-\\nplished chiefly by the external recti muscles, assisted by the\\nsuperior and inferior oblique muscles.\\n1 In discussion of a paper read by Dr. Noyes, at the Oph. Sec, Academy\\nMed., January 16, 1899.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0275.jp2"}, "276": {"fulltext": "258 THE REFRACTIOX OF THE EYE\\nSursumduction means, literally, to turn upward. It is ac-\\ncomplished chiefly by the superior recti muscles, but is assisted\\nby the inferior oblique muscles.\\nDeorsumduetion means, literally, to turn downward. It is\\naccomplished chiefly by the inferior recti muscles, but is\\nassisted by the superior oblique muscles.\\nMethods of measuring the ocular muscles. In my office I\\nmeasure the strength of the different ocular muscles, that is,\\nmeasure the adduction, abduction, sursumduction, with prisms,\\nin the simplest way possible, as follows With both eyes open,\\nand directed to a candle flame twenty feet distant, I begin\\nwith the lowest prism in the case, with the edge or apex of the\\nprism over the muscle to be tested, and gradually increase the\\nstrength of the prisms until the patient sees double. For\\nexample, to get the adduction, that is, to measure the strength\\nof the internal recti, I begin with a prism 1\u00c2\u00b0, apex inward, and\\ngradually increase its strength till the patient sees double, or\\ncan no longer bring the images together after they are doubled\\nfor it often happens that a patient will see double when a\\nprism of certain power is first placed in front of the eye, espe-\\ncially in measuring for adduction but, after a second or two,\\nthe images will come together. Another prism, a little\\nstronger, is then to be tried, till a prism is reached that the\\npatient cannot fuse the images with after they have once been\\nseparated. Say the jDatient overcomes a 14\u00c2\u00b0 prism, apex in,\\nbut that a 15\u00c2\u00b0 prism makes him see double. His adduction\\n(prism convergence) is 14\u00c2\u00b0.\\nTo measure abduction, place apex of the prism outward\\nover the external rectus muscle, and gradually increase its\\nstrength, till the patient can no longer see the candle single.\\nFor example, say he can overcome a 7\u00c2\u00b0 prism, but not 8\u00c2\u00b0. His\\nabduction is 7\u00c2\u00b0.\\nTo measure sursumduction, place apex of the prism upward,\\nin front of the right ej e, and increase its strength till the", "height": "4245", "width": "2805", "jp2-path": "refractionofeye00davi_0276.jp2"}, "277": {"fulltext": "INSUFFICIENCIES OF THE OCULAR MUSCLES 259\\npatient sees double. For example, say the patient overcomes\\nS\u00c2\u00b0 prism, but not 4\u00c2\u00b0. His right sursumduction is 3\u00c2\u00b0. The left\\nsursumduction is obtained by placing apex of the prism\\nupward, in front of the left eye, just as in the right.\\nTo measure deorsumduction, place apex downward, in front\\nof the right eye, and increase its strength till the patient sees\\ndouble, to get right deorsumduction and, to get left deorsum-\\nduction, place apex down, in front of the left eye, and increase\\nits strength till patient sees double.\\nIt is customary in practice to measure only the adduction,\\nabduction, and sursumduction.\\nThe old equilibrium test^ of Von Graefe, that is, where a\\nvertical diplopia is first produced in order to measure the\\nstrength of the muscles that move the eye in the horizontal\\nplane, and a horizontal diplopia is produced in order to meas-\\nure the muscles in the vertical plane, is very defective, and\\ngives exaggerated results in nearly every case. This is due to\\nthe fact that the instant you produce a diplopia with prisms\\nyou at the same instant take away from the eyes the desire,\\nand, to a certain extent, the power, of fusing the images in the\\ntwo eyes. As the desire and the capacity of fusing the two\\nimages into one, that is, of obtaining single binocular vision, is\\nthe greatest stimulus the eyes have for keeping themselves bal-\\nanced and in equilibrium, this equilibrium test, at the very\\noutset, places the eyes in the most unfavorable condition for\\ntesting for equilibrium or balance. This test is to be con-\\ndemned therefore. The simple prism tests for ascertaining the\\npower of adduction, abduction, sursumduction, are much more\\nreliable.\\nIf I am not satisfied with the simple prism tests, I find the\\namplitude of convergence after Landolt s method. To get the\\n1 This same test was later much used in America by Stevens and his pupils.\\nWithin the last few years, however, Stevens has invented an instrument for\\nmeasuring the muscles, whereby he avoids diplopia in the beginning of the test.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0277.jp2"}, "278": {"fulltext": "260 THE REFRACTIOX OF THE EYE\\nmaximum convergence, his method is to bring a narrow line of\\nlight (obtained by putting a metallic shield round a candle,\\nand cutting a vertical slit in this shield three millimeters wide),\\ntoward the eyes, in the median plane, until the patient sees it\\ndouble. Then he measures the distance from the eyes on a\\ntape marked in centimeters. This number of centimeters di-\\nvided into a hundred gives the number of meter angles of con-\\nvergence of the eyes for the near point. For example, say the\\nline of light was brought to the distance of five centimeters\\nwhen it doubled. Five divided into one hundred gives twenty,\\nthe number of meter angles of convergence for this distance\\n(^punetum proximum).\\nBut, to get the minimum amount of convergence of which\\nthe eyes are capable, we must resort to measurement by prism\\ndivergence for it is a well-known fact that most eyes can\\ndiverge slightly even after their visual lines are parallel. As\\nthe distant point of convergence (^punetum remotum^ is at\\ninfinity when the visual lines are parallel, it is manifest that, if\\nthe eyes can diverge further after this, the distant point, under\\nsuch circumstances, must be beyond infinity or, if prolonged\\nbackward, the visual lines would converge to a point back of\\nthe eyes, evidently not to be measured by tape or rule. In\\norder to get this point, therefore, we measure the amount or\\nangle of deviation that the eyes are capable of. as in measuring\\nfor abduction, by means of prisms with apex outward the\\nstrongest prism the patient can overcome before seeing double,\\ndivided by two, representing the angle of deviation.^ Then,\\nfrom the size of the angle of divergence, according to a simple\\nformula given by Landolt, we can calculate the distance of the\\ndistant point (^punctum remotimi) back of the eye.\\n1 A black line on a white piece of paper serves the same purpose.\\n2 The reason that the prism has to be divided by two is because a prism\\ncauses a deviation of only one-half the number of degrees in the prism. At\\nleast, this holds true in prisms of low or moderate degree of power.", "height": "4257", "width": "2784", "jp2-path": "refractionofeye00davi_0278.jp2"}, "279": {"fulltext": "mmm\\nINSUFFICIENCIES OF THE OCULAR MUSCLES 261\\nAs Lanclolt says: It is not difficult to show the relation\\nexisting between the strength of any prism and the number of\\nmeter angles which expresses the deviation produced. For a\\nbase line (or distance between the centers of rotation of the\\ntwo eyes) of 58 millimeters, as in children, a meter angle cor-\\nresponds to r 39 39 say 100\\nThe deviation produced by a prism may be taken as half\\nits angle of opening, which is marked on each prism in our trial\\ncases, or on the hand of the double prism. Therefore, a prism\\nof X\u00c2\u00b0 will produce a deviation of or of It is only\\nnecessary to divide this value by 100 in order to obtain, the\\ncorresponding number of meter angles:\\njli X lUU\\nThis formula reduced to its simplest expression becomes\\nthat is to say, we have only to multiply the number of the\\nprism hy 3, and divide the prism hy 10, in order to find in meter\\nangles the deviation for a base line of E S millimeters.^\\nWhen the prism is held before one eye only, as in the\\ndetermination of the minimum of convergence by the double\\nprism, its action is divided between the two eyes. The total\\ndeviation gives for each eye A prism of 6\u00c2\u00b0 produces\\na deviation of yf 1.8 meter angles. But if both eyes con-\\ncur to neutralize this effect, each eye need only change its\\ndirection 0.9 meter angle. It is only when the prism of\\n6\u00c2\u00b0 is placed before each eye that the full result of 1.8 meter\\nangles is obtained always, of course, for a base line of dS\\nmillimeters.\\nWhen the base line is longer, for example, 64 mm., as in\\nadults, tlie meter angle becomes 1\u00c2\u00b0 50 110 and the formula\\n3 X\\nbecomes for the deviation corresponding to the prism of X\u00c2\u00b0,\\n1 Italics mine.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0279.jp2"}, "280": {"fulltext": "262 THE KEFRACTION OF THE EYE\\nor for the effect produced on each eye when the prism i\\nplaced before one qjq only.\\nSay in the above case, when the positive convergence was\\n20 meter angles, the patient was able to overcome only 4\u00c2\u00b0\\nprism, apex outward. We will assume also that it is the case\\nof a child with a distance between the centers of rotation\\nof the two eyes of 58 mm. Landolt s formula would give\\n\u00e2\u0080\u0094^=1.2 meter angles of divergence (negative conver-\\ngence). As we placed the 4\u00c2\u00b0 prism in front of but one eye, it\\nequalled the strength of only 2\u00c2\u00b0 prism in front of both eyes,.\\n4x3\\nwhen our formula would be 0.6 meter angle.\\nXow to get the amplitude of convergence we subtract the\\n0.6 meter angle of divergence (negative convergence) from\\nthe 20 meter angles of positive convergence which we got\\nby actual measurement with the tape. This would give\\n20.6 meter angles as the amplitude of convergence in the\\nabove case.\\nLandolt has given 10.50 meter angles as the average ampli-\\ntude of convergence, and I may say I have found his the most\\nsatisfactory way of measuring the convergence. Even when\\nthe measurement b}^ means of prisms (prism convergence test)\\nindicates an insufficiency, if the amplitude of convergence\\ncomes near the normal, I have found that simply correcting\\nthe error of refraction is all that is necessary in most cases,,\\naided in some, however, by exercise and tonics.\\nStrength of the different ocular muscles as expressed in adduc-\\ntion^ abduction^ sursumduetion their direct and relative values.\\nIncidentally, I may remark here that our notions in regard to\\nthe strength of the different ocular muscles, as expressed in\\nthe terms adduction, abduction, sursumduetion, and their rela-\\n1 Landolt, Refraction and Accommodation of the Eye, p. 287.", "height": "4244", "width": "2698", "jp2-path": "refractionofeye00davi_0280.jp2"}, "281": {"fulltext": "INSUFFICIENCIES OF THE OCULAR MUSCLES 263\\ntive values, have undergone some change since the publication\\nof a paper by Bannister on the Dynamics of the Ocular\\nMuscles, in the Annals of Ophthalmology/, January, 1898.\\nBannister measured the muscles in the eyes of one hundred\\nsoldiers in the United States army who were in rugged health;\\nin fact, had to undergo the most rigorous physical examination\\nbefore enlistment. They were required to read (Snellen)\\nwith each eye and without glasses before entering the service.\\nSo he had ideal subjects for testing the ocular muscles.\\nThe results he arrived at vary widely from those laid down\\nby most authorities, both as to the actual strength of the\\ndifferent muscles and of their relative values. As his experi-\\nments were made on absolutely healthy subjects, so far as\\nphysical examination was able to decide, on eyes with perfect\\nvision and no asthenopia, and the tests made with much care,\\nthey must be given great weight. Bannister cites Risley s\\npaper of similar measurements made on a series of twenty-five\\nnon-asthenopic persons, and says he is the only one other than\\nhimself to make such examinations in the healthy non-asthe-\\nnopic subject. I may say, however, that Roosa,i in 1890,.\\nreported a series of 103 such cases, the examinations having\\nbeen made for him by Dr. A. B. Deynard with the phorometer\\nof Dr. Stevens, and after his method of testing. Out of the\\n103 cases, 17, or sixteen per cent, were found to have muscular\\nequilibrium 84, or eighty-one per cent, had a want of mus-\\ncular equilibrium, so-called heterophoria of these 27, or\\ntwenty-six per cent, had deviation outward, exophoria, insuffi-\\nciency of the interni and 74, or seventy-one per cent, ex-\\nophoria in accommodation 16, or fifteen per cent, had deviation\\ninward, or esophoria, insufficiency of the externi 7 had es-\\nophoria in accommodation 11, or ten per cent, had hyper-\\nphoria, a tendency of the right or left visual line upward 24\\nhad hyperphoria in accommodation. A reexamination of rive\\n1 Med. liecord, April 19, 1890.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0281.jp2"}, "282": {"fulltext": "264 THE REFRACTIOX OF THE EYE\\nof these patients all shoAvecl a cliange in the muscular examina-\\ntion from that found at first. This is an important observa-\\ntion, since it proves, as asserted by Starr and others, that the\\nmuscular power in the same eyes is not fixed, but variable.*\\nAdduction^ as measured by prisms (prism convergence), the\\ncommon method pursued in office practice, bases out before\\nthe eyes, amounts for the distance vision to from 35\u00c2\u00b0 to 50\u00c2\u00b0.\\nAt least this is the standard given by most authorities. Ban-\\nnister, in his experiments on one hundred healthy, non-asthe-\\nnopic subjects, gives the average adduction as only 14.1\u00c2\u00b0. He\\nsays in regard to it I am perfectly willing to place myself\\nupon record as asserting that the teaching of the authorities\\nthat healthy eyes should show upon demand a prism conver-\\ngence for distance of 30\u00c2\u00b0, or 35\u00c2\u00b0 to 50\u00c2\u00b0, is absolutely misleading\\nand erroneous. In my series of examinations the highest\\namount of adduction for 6 meters reached was 26\u00c2\u00b0, and this\\namount could only be obtained in one case, and that, too, only\\nafter most careful effort. We are told that in our office con-\\nsultations our patients should show this amount of adduction\\n(30\u00c2\u00b0 or 35\u00c2\u00b0 to 45\u00c2\u00b0 or 50\u00c2\u00b0), and that if they do not exhibit it we\\nmust consider their convergence to he weak. If we accept as true\\nthe standard given above, every one of my healthy cases should\\nhe charged ivith convergence insufficiency.\\nHe, however, remarks that b}^ prism practice most, if not\\nall, of these could be made to show an adduction of 50\u00c2\u00b0.\\nBut, as he again says, that is not the point at issue. It is\\nthe first test, and not when they have had previous tests, prism\\npractice, if you please, of which he speaks.\\nAhduction^ as measured b}^ prisms (prism divergence), for\\ndistance amounts, as a rule, to 8\u00c2\u00b0, according to the older\\nstandards. Risley gives the same amount for healthy non-\\nasthenopic subjects. Bannister gives 7\u00c2\u00b0 as the average abduc-\\ntion for his one hundred healthy soldiers, but in manj of his\\ncases it was considerably less. In this connection he calls", "height": "4249", "width": "2698", "jp2-path": "refractionofeye00davi_0282.jp2"}, "283": {"fulltext": "INSUFFICIENCIES OF THE OCULAR MUSCLES 265\\nattention to the claims made by Noyes, Duane, and others that\\nabduction should not fall below 6\u00c2\u00b0 for the distance, and that an\\nabduction of less than 5\u00c2\u00b0 will in most cases be pathological.\\nIn other words, that an insufficiency of the external recti is\\npresent.\\nBannister says, If these views are correct, twenty-two, or\\nat least seventeen, of my absolutely healthy cases, would fall\\nin the pa.thological class. He does not believe them to be\\nin this class, however, for every one of the twenty-two cases\\nshowed perfect muscle balance for the near point, and only\\nnine a want of balance of the muscles for the distance, and\\nthat in only a slight degree.\\nThe same author also explodes the old idea that for the\\nnear point we may expect an insufficiency of the internal recti\\nof about 5\u00c2\u00b0 prism, and that such a condition is physiological\\n(Duane). In fact, he demonstrates that muscle balance is more\\nfrequent for the near point than for the distance, for in his one\\nhundred cases he found perfect muscle balance for the distance\\nin but sixty cases, while for the near point it was present in\\neighty-two cases. Moreover, he showed in the thirteen cases\\nthat had a divergence excess for the distance that eleven of\\nthem had perfect muscle balance, and only two of them showed\\nslight diverging tendency for the near point. This is just the\\nreverse of what would be expected according to the old stand-\\nards, and can be explained only on the ground. Bannister\\nthinks, that orthophoria is the physiological state for the\\nnear and this, notwithstanding the opposite opinion held\\nby such eminent authorities.\\nIn regard to the ratio between adduction and abduction, or\\ntheir relative strength as measured by prisms. Bannister thinks\\nthat there cannot be any definite relation fixed; and is of the\\nopinion that older standards of 6 to 1, or 7 to 1, without pre-\\nvious training of the convergence with prisms, is much too\\nhigh. His own results would indicate that relation in healthy.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0283.jp2"}, "284": {"fulltext": "266 THE REFRACTION OF THE EYE\\nnon-astlienopic subjects to be about 2 to 1, since the average\\nadduction in his cases was 14.1\u00c2\u00b0, while the average abduction\\nwas 7\u00c2\u00b0.\\nSursumduction, as measured by prisms, base down, amounts\\nto 2\u00c2\u00b0 to 4\u00c2\u00b0.\\nDeorsumduction, as measured by prisms, base up, amounts to\\n2\u00c2\u00b0 to 4\u00c2\u00b0.\\nBannister, in his healthy subjects, gave 2\u00c2\u00b0 as the average,\\nboth of sursumduction and deorsumduction, and says in regard\\nto their relative strength, It seems well settled, also, that\\nthe power in each direction of the vertical plane is about the\\nsame^ and that deGrsitmduction shoidd not be expected to exceed\\nthe antagonistic function as held by some.\\nSince I have quoted so liberally from Bannister s paper,^ I\\ngive his conclusions, which, since they are based on the ex-\\naminations made in perfectly healthy subjects with non-asthe-\\nnopic eyes, must be admitted to form a good standard for\\nabnormal conditions\\n1. The degree of adduction (prism convergence) given by\\nmost writers as proper for 6 meters, cannot be reached by hecdthy\\neyes except after practice in the use of j^^risms. Hence the stand-\\nard is too high for attainment in the first office examination,\\nand hence the method of measuring the convergence by adductive\\np risms is unreliable and misleading.\\n2. That t\\\\\\\\Q prism convergence for near (33 centimeters) is\\nalso misleading, and is not an accurate test of the real power of\\nconvergence,\\n3. That the determination of the punctum jyroximum of con-\\nvergence^ and the calculation of the maximum convergence after\\nthe method of Landolt, are the only true tests of the real poiver\\nof convergence., or the p)ositive convergence.\\n4. That, contrar}^ to the generally received views, abduction\\n(prism divergence) for distance can fall well below 6\u00c2\u00b0 in\\n1 Annals of Ophthalmology, St. Louis, January, 1898.", "height": "4248", "width": "2805", "jp2-path": "refractionofeye00davi_0284.jp2"}, "285": {"fulltext": "INSUFFICIENCIES OF THE OCULAR MUSCLES 267\\n]iealtliy eyes, and that, consequently, it is wrong to assume upon\\nthis basis alone that such cases are pathological.\\n5. That there exists in healthy eyes no positive, definite\\nrelation between prism convergence and prism divergence for\\ndistance, and that it is not correct to claim that such eyes\\nshould without practice ivith prisms show at 6 meters a ratio\\nbetween these functions of 3 to 1, or 7 to 1, in favor of con-\\nvergence, not permitting abduction to fall below 6\u00c2\u00b0.\\n6. That we may expect sursumduction and deorsumduc-\\ntion for distance to be about the same in degree in about 70\\nper cent of healthy eyes each function reaches 2\u00c2\u00b0 (prism)\\nin amount.\\n7. That in healthy eyes orthophoria exists in about 60 per\\ncent of the cases /or distance^ and in about 82 per cent for near,\\nand that it is wrong to hold that orthophoria for near is abno7nnal,\\nand to he vieived with suspicion.\\n8. That in about 40 per cent of healthy individuals who\\nhave never had a symptom of eye trouble there may be found a\\nslight heterophoria for distance., and that, therefore, we should\\nnot assume that every patient showing a slight degree of im-\\nbalance is on that account alone in a serious condition.\\nThe mere fact, however, that the examinations from which\\nthese conclusions of Bannister are drawn were made on eyes\\nwith little or no refractive error, without asthenopic symptoms,\\nand in healthy subjects, must be borne in mind for it may\\nbe stated as a general principle that hypermetropic errors of\\nrefraction favor convergence, while myopic favor divergence, of\\nthe eyes. Hence, we may find a predominance of the one or the\\nother, accordingly as the eye is hypermetropic or myopic and\\nthis should be remembered when refractive errors are present.\\nBut, taking refractive cases as they come, I must say my\\nexperience as to the strength of the muscles, actual and rela-\\ntive, more nearly agrees with that of Bannister s than with the\\nordinary standards as given in the text-books of to-day.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0285.jp2"}, "286": {"fulltext": "268 THE REFRACTIOX OF THE EYE\\nAs a rule, strabismus cases should not have glasses fitted\\nuntil three years of age, for under this age they can seldom be\\nmade to wear the glasses or, if they do wear them, be made\\nto look through them they, most of the time, looking under or\\nover them. Then again, the danger of a young child break-\\ning the glasses and injuring the eyes is not to be forgotten.\\nI have fitted two cases of glasses at three years of age\\nbut, in each case, the child was very tractable, and wore the\\nglasses as directed by the mother. Dr. Dennett, of this\\ncity, has, I believe, fitted children at the tender age of two\\nyears.\\nOf course, as soon as the eyes are adjusted to glasses they\\nare in a better condition to be used together, and the stimulus\\nto single binocular vision is much enhanced, if amblyopia is\\nnot too marked.\\nIncidentally, in this connection, I might say that, with rare\\nexceptions, no operation should be done on a squinting eye in\\na child under four years of age and, as a rule, it is safer to\\nwait till the patient is five or six years old. It is a well-\\nestablished fact that many children grow out of a conver-\\ngent squint. I have seen several patients who gave a history\\nof squinting in childhood, but who had perfectly straight eyes\\nwhen they came under my care in later life, and without\\n1 In reply to a note from me, I received the following letter from the\\ndoctor\\nDear Doctor Davis,\\nIn 1889 I had a little girl for a patient who was fourteen months old, and\\nwho had had a well-marked convergent strabismus for some weeks. She had\\nby ophthalmoscopic examination, upright image, Hm. 2. 0. U.\\nI ordered glasses, and asked the mother to see if she could make the child\\nwear them. I have not seen the child since, but the mother told me that the\\nglasses were worn most of the time for two weeks, when the squint disappeared,\\nand the baby was allowed to go without them.\\nThe mother was an intelligent woman, and I believed her.\\nYours, etc.", "height": "4242", "width": "2812", "jp2-path": "refractionofeye00davi_0286.jp2"}, "287": {"fulltext": "METHODS OF MEASURING STRABISMUS 269\\nhaving had any operation on the eyes.^ While writing this\\nchapter, two such cases have come under my care, both of\\nwhom had squinted in childhood, but both had recovered from\\nit without glasses and without operation. In each case there\\nwas a high degree of compound hypermetropic astigmatism,\\nwith marked amblyopia in the eye that had squinted. Both\\ncases are reported in this chapter farther on.\\nDr. Roosa tells me he has the history of at least one hun-\\ndred cases who had squinted in childhood, but subsequently\\nrecovering without operative procedure. In fact, testimony of\\nlike character is to be had on all sides so it behooves us, in\\nstrabismus cases, not to be in too great a hurry about operat-\\ning, especially in convergent strabismus. It is best first to\\nbegin by fitting the patient correctly to glasses under a mydri-\\natic, and letting these glasses be worn continuously for a num-\\nber of months, or years, if the patient is very young, before\\noperating.\\nFor measuring the amount of strabismus, there are two or\\nthree very simple methods (1) By means of a very simple in-\\nstrument, the strabometer of Laurence, represented in the cut\\nbelow, the deviation of the eye can easily be measured. This\\ninstrument is numbered in millimeters from the center, 0, lat-\\nerally in each direction. By placing this instrument directly\\nbeneath the deviating eye, while the good eye is fixed on some\\n1 1 have seen one case, in fact, within the year, where a convergent strabis-\\nmus developed, into a divergent strabismus, and without any operative procedure\\nwhatever. The patient, a gentleman of much intelligence, aged thirty-live years,\\ngave a history of marked inward squinting of his left eye when a child which got\\nwell of itself, without glasses and without operation, by the time he was twelve\\nyears of age. Although he always saw poorly with the left ej- e, he did not have\\nglasses fitted till twenty-one years of age, which glasses he has worn since.\\nAbout three years ago he noticed that his left eye turned outward at times,\\nand for the last few months continually. There is a divergence now of 10^.\\nR. V. f\u00c2\u00a7 1-0- W. 1 D. .75 cyl., 90\u00c2\u00b0 L. V. j^ir W. -H 3 D. 1 D.\\ncyl., 90\u00c2\u00b0. Binocular single vision is absent. There is no lesion in the fundus of\\neither eye. This is the only case of the kind that has come under my observa-\\ntion.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0287.jp2"}, "288": {"fulltext": "TO\\nTHE KEFRACTIOX OF THE EYE\\ndistant point, and noting the number of millimeters distance\\nthe center of the cornea is from the center of the instrument,\\nwe at once ascertain the amount of the deviation in millimeters.\\nAs each millimeter of deviation represents\\nrouglily an angle of 5^ we can reduce the\\nlinear deviation to an equivalent expressed\\nin degrees, by simply multiplying the num-\\nber of millimeters of deviation by live for\\nexample, say the linear deviation was three\\nmillimeters, this reduced to degrees would\\nbe 15^ and so on.^\\n(2) The extent of deviation or squint-\\ning of an eye may be measured with the\\nperimeter. Place the patient in front of\\nthe instrument, with the deviating eye in\\nFig. lOL\u00e2\u0080\u0094 Strabometer Hue with the Center of the arc, just as if\\nto take the lield of vision. Leave both\\neyes open, and have the good one directed to a distant object\\n(20 feet) directly in front then carry a candle along the arc\\nof the instrument until the image of the flame is at the center\\nof the cornea of the deviating eye. The position of the candle\\non the arc marks the number of degrees of deviation.\\n(3) A simple method, without the use of any instrument\\nwhatever, is as follows Have the patient look at a distant\\nobject directly in front of him, then make an ink-dot on the\\nlower lid of the deviating eye. directly below the outer margin\\nof the cornea: also a dot on the lid just below tlie outer mar-\\ngin of the cornea of the straight eye. Xow cover the straight\\neye with a card, and let the patient fix the object with the bad\\nor crooked eye. Of course, the eye will liave to move from its\\noriginal position to do this, and the good eye back of the card\\nwill squint as the bad eye had when uncovered. Again mark\\n1 Perhaps each milUmeter of deviation vrould be more nearly represented\\nbv an ansle of 5^-, rather than the even number 5", "height": "4236", "width": "2698", "jp2-path": "refractionofeye00davi_0288.jp2"}, "289": {"fulltext": "ILLUSTRATIVE CASES 271\\nthe position of the outer margin of the cornea on the lower lid\\nof the bad eye also the position (back of the card) of the outer\\nmargin of the cornea of the good eye on the lower lid. The\\ndeviation in each eye will be found to be exactly the same.\\nThat in the bad eye is called the primary deviation, that in the\\ngood eye the secondary deviation. The distance between the\\ntwo dots on the lids will be the amount of deviation. To get\\nit in degrees, multiply the number of millimeters by 5 for\\nexample, say the distance between the dots on each side is\\n4 millimeters. This multiplied by 5 gives 20, the number of\\ndegrees of deviation.\\nIf, as sometimes happens, the power of fixation is lost in\\nthe squinting eye, even when the good eye is covered, this last\\ntest cannot be made. The approximate amount of the devia-\\ntion can be determined in such cases by having the patient\\nlook at a distant object directly in front of him, then measure\\nthe distance between the external canthus aiid the outer edge\\nof the cornea in each eye. The difference between the two\\namounts is the extent of the deviation of the squinting eye\\n(Fuchs).\\nFor more complete tests for determining the amount of\\ndeviation or squint in an eye, and for the .indications for oper-\\nating on such eyes, I must refer the reader to the larger text-\\nbooks. An intimate knowledge of the anatomy and ph3^siology\\nof the muscles of the eye, as well as an acquaintance with the\\nrefractive conditions, is necessary for a full understanding of\\nthe subject.\\nCase XCV. Convergent strabismus left eye; Simple Iiyper-\\nmetropia both eyes; Cure by means of glasses and a mydriatic.\\nJuly 7, 1892, Hugh G., aged four years, in good health, was\\nbrought to me by his mother on account of the left eye turning\\ntoward the nose. The eye has squinted since he was a baby.\\nHe had diphtheria when one year of age, but the eye turned\\nbefore lie had diphtheria. The patient has a twin sister and", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0289.jp2"}, "290": {"fulltext": "272 THE REFRACTIOX OF THE EYE\\na younger brother, whose eyes are perfectly straight. Father\\nand mother s ejes are straight.\\nOphthalmometer. Astigmatism with the rule, .50 D., axis\\n90\u00c2\u00b0 180\u00c2\u00b0 each eye. As the patient was too young to test\\nwith the test cards, I made no attempt at subjective examina-\\ntion.\\nOphthalmoscope. H. 2 D. right eye; H. 4 D. left eye.\\nOrdered atropine solution, 2 gr. to ^i, to be used three times a\\nday for one week. Before instilling the atropine solution, I\\nmeasured the amount of deviation, and found it to be between\\n15\u00c2\u00b0 and 18\u00c2\u00b0. Under atropine, the ophthalmoscope showed H.\\n4 D. right, and H. 5 D. left. The retinoscope confirmed this.\\nA -f 3.50 D. spherical glass right, and 4.50 D. left, were\\nordered for constant wear and one drop of the atropine solu-\\ntion, in each eye, once a day, was continued for two weeks.\\nAt the end of that time the eyes were much improved atro-\\npine, one drop every other day, was used for two weeks longer,\\nthen it was discontinued altogether. At the end of six months\\nthe patient had perfectly straight eyes with the glasses on. If\\nthe glasses were removed, the patient would turn the left eye\\ninward, but not as far as when first seen.\\nI have seen this child from time to time for the last seven\\nyears, and the eyes remain perfectly straight with glasses, but\\nhave a tendency to turn for the near point unless the glasses\\nare on.\\nWhen the patient arrived at the school age and knew his\\nletters, I tested both eyes carefully for acuteness of vision, to\\nsee if any amblyopia was present in the eye that had squinted.\\nThe vision in each eye was (Snellen) with his glasses on.\\nIf he ever had amblyopia in the left eye, it had disappeared\\nwith use and the aid of the glasses. Single binocular vision\\nis present.\\nOperative proceedings in this case when first seen would\\nhave been unwise. The motility of the eye, the acuteness of", "height": "4260", "width": "2783", "jp2-path": "refractionofeye00davi_0290.jp2"}, "291": {"fulltext": "ILLUSTRATIVE CASES 273\\nvision in each eye (when it can be taken), the kind of squint,\\nalternating or fixed, are all factors which should be weighed\\nbefore any operation should ever be undertaken.\\nThe ophthalmometer was a valuable means for eliminating\\nthe factor of corneal astigmatism at the outset of the case.\\nRetinoscopy was of value, also, as atropine -had to be used.\\nIn fact, it is in just such cases that these objective tests are of\\nsuch great importance.\\nCase XCVI. Periodic convergent strabismus right eye\\nSimple hypermetropia each eye Cure effected in three months hy\\nmeans of glasses alone. November 27, 1898, Wm. M., aged\\nseven years, in \u00c2\u00a7ood health, came to the clinic of Drs. Lewis\\nand Van Fleet, because of squinting of the right eye in-\\nward at times for the last year. None of his family is cross-\\neyed. As is often the case, the mother attributes the cause to\\na fall on the head when the patient was a baby, although the\\neye did not begin to squint till he was about six years of age.\\nThe right eye deviates inward about 15\u00c2\u00b0.\\nOj)hthalmometer. Astigmatism with the rule, 1 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 in each eye.\\nTest cards and trial lenses.\\nR. V. 1^ f-l W. .50 D. cyl., 90\u00c2\u00b0.\\nL. V. 1^ ff W. .50 D. cyl., 90\u00c2\u00b0.\\nReads Jaeger No. 1 from 4 to 12 inches.\\nOphthalmoscope. H. 2 D. in each eye.\\nOrdered atropine solution, 2 gr. to 5i, to be instilled, three\\ntimes a day, for four days, and to return for a second test.\\nSecond test ophthalmometer shows astigmatism with the\\nrule, .50 D., axis 90\u00c2\u00b0 or 180\u00c2\u00b0 in each eye.\\nTest cards and trial lenses.\\nR.V. fJ:||-W. +3D.\\nL.V. =fMlW. -I- 3D.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0291.jp2"}, "292": {"fulltext": "274 THE REFHACTION OF THE EYE\\nOphthalmoscope. H. 3 D. in each eye,\\nA plus 3 D. sphere was ordered for each eye, to be worn\\nsteadily. In three months time this patient ceased to squint\\naltogether, although he went to school, and used the eyes for\\nclose work.\\nIt is hardly. necessary, I suppose, to say that a periodic\\nsquint, in young subjects es^Decially, should not be operated\\nupon. Certainly not until glasses have been given a thorough\\ntrial aided, if need be, by having a weak solution of atropine\\ninstilled into the eyes, once a day, for a few weeks at a time\\nthen intermit, and repeat once or twice. Covering up the\\ngood eye for half an hour, once or twice a day, is valuable in\\nthese cases. The stereoscope is valuable also. If, after a few\\nweeks, or months at furthest, the squint is not improved, but\\ngrows worse, becoming a permanent squint, an operation is to\\nbe considered, and no more time should be wasted.\\nIn the case just reported, the ophthalmometer showed astig-\\nmatism of 1 D., before the mydriatic was used, and the patient\\naccepted .50 D., the correct amount after deducting .50 D., as\\nis ordinarily done in astigmatism with the rule. After using\\nthe mydriatic, however, the instrument showed only .50 D.,\\nand the patient accepted only a spherical glass, as is customary\\nwhen there is only .50 D. of corneal astigmatism with the rule.\\nThis discrepancy is to be explained in one of two ways first,\\nin the first test there might have been an error in observation,\\nwhich seems unlikely, as the patient accepted .50 D. cyl.,\\n90\u00c2\u00b0 second, when the mydriatic was used it relaxed the accom-\\nmodation, the convergence was relaxed at the same time, and\\nthis relaxation of the convergence took some pressure off the\\nhorizontal meridian of the cornea, and, in that way, lessened\\nthe astigmatism, perhaps I rather incline to the latter opin-\\nion. That the straight muscles do exert some influence on the\\ncurvature of the cornea is proved by a case reported by me in\\nthe 3Ia?ihatta7i Eye and Ear Hosp)ital Reports^ 1895, p. 49.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0292.jp2"}, "293": {"fulltext": "ILLUSTRATIVE CASES 275\\nA favoring factor in this case, in aiding the eyes to become\\nstraight without operation, was the fact that there was no\\namblyopia present in either eye, for this reason the fusion of\\nthe images of the two eyes was- greatly facilitated, and the\\ndesire for single binocular vision increased. Single binocular\\nvision was restored in this case.\\n.Even where the squint is constant, but where the patient\\nsquints first one eye, then the other, at will, and without the\\nnecessity of covering either eye, the so-called alternating\\nsquint, the visual acuity is apt to be the same, or nearly the\\nsame, in each eye, and to be very good, or better. In such\\ncases, the chances for cure with glasses alone are much better\\nthan where amblyopia is present in one eye.\\nCase XC VII. Convergent strabismus right eye Compound\\nIfiypermetropic astigmatism both; Amblyopia hoth^ hut more\\nmarked m the right; Glasses and one operation necessary for\\na cure. September 11, 1891, Grace C, aged eight years, came\\nto the clinic of Drs. Lewis and Van Fleet because of squint-\\ning of the right eye, which has squinted constantly for four\\nyears. She has not had treatment of any kind thus far.\\nOphthalmometer. Astigmatism with the rule, 1 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 each eye.\\nTest cards and trial lenses. (Under atropine mydriasis).\\nR. V. f^\\\\ t;Vo W. 1 D. .50 D. cyl., 90\u00c2\u00b0.\\nL. V. f^ 1^ W. 3 D. .50 D. cyl., 90\u00c2\u00b0.\\nOphthalmoscopic. 5 D. right eye H. 1 D. left eye.\\nOrdered the glasses that were accepted under atropine,\\nwhich were worn continuously for six months, but the squint\\nremained. At the end of this time a tenotomy of the right\\ninternal rectus was done. The qjq was made perfectly\\nstraight with the operation, and by continued use of the\\nglasses was kept straight, although single binocular vision\\nwas not restored.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0293.jp2"}, "294": {"fulltext": "276 THE REFRACTIOX OF THE EYE\\nIt will be noticed that tlie amblyopia was marked in the\\nright or squinting eye, while it was present to a moderate\\ndegree in the non-squinting eye. The ophthalmometer in\\nsuch cases as this is very useful, for with so marked amblyopia,\\nas was present in the right eye, glasses do not improve the\\nvision much, no matter what glasses are given, yet it is\\nimportant to give the correct glass. If we can meas-\\nure the astigmatism in such cases, and have that impor-\\ntant factor satisfactorily disposed of, it greath facilitates\\nmatters.\\nCase XCYIII. Convergent strahismus riglit eye; Large\\namount of compound hypermetropic astigmatism in each eye^\\nmore marJ^ed in the right eye; Amblyopia in each; Cured by\\nglasses and one operation. October 9, 1894, J. R., aged nine\\nyears, came to the clinic of Drs. Lewis and Van Fleet to have\\nthe right eye straightened. The right e3^e has turned inward\\nsince he was a small child, and now has a squint of 20\u00c2\u00b0 or\\nmore. He can fix with the squinting eye when the good one\\nis covered. None of the family but himself ever had cross-\\neye.\\nOphthalmometer. Astigmatism with the rule, 2 D., axis\\n120\u00c2\u00b0 or 30\u00c2\u00b0 right ej^e 1.50 D., axis 60\u00c2\u00b0 -j- or 150\u00c2\u00b0 left\\neye.\\nTest cards and trial lenses.\\nM U -3 D. 1.50 D. cyl., 120\u00c2\u00b0.\\nL. V. ^Vo H D- 1 D. cyl., 60\u00c2\u00b0.\\nOphthalmoscop)e. R. 3 D. at 120\u00c2\u00b0 and H. 5 D. at 30\u00c2\u00b0\\nright e3-e H. 4 D. at 60\u00c2\u00b0 and H. 5 D. at 150\u00c2\u00b0 left eye.\\nOrdered atropine solution, 4 gr. to 3i, three times a day for\\nfour days.\\nTest under atropine ophthalmometer showed the same\\nreading as in the first test.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0294.jp2"}, "295": {"fulltext": "ILLUSTRATIVE CASES 277\\nTest cards and trial lenses.\\nR- 2-Vo f PV. 4 D. 2 D. cyl., 120\u00c2\u00b0.\\nL. V. 2^ f W. 5 D. 1.50 D. cyl., 60\u00c2\u00b0.\\nOpJithalmoscojJe.\u00e2\u0080\u0094B.. 4 D. at 120\u00c2\u00b0 and 6 D. at 30\u00c2\u00b0 right\\n\u00e2\u0080\u00a2eye H. 5 D. at 60\u00c2\u00b0 and H. 6 D. at 150\u00c2\u00b0 left eye.\\nTwo days later a third test was given, the atropine having\\nbeen stopped. The ophthalmometer showed the same reading\\nas on previous occasions. With the test cards and trial lenses\\nthe patient accepted the same spherical glass as when under\\natropine, but one-half diopter less of astigmatic correction.\\nOrdered\\n4 D. 1.50 D. cyl., 120\u00c2\u00b0 right;\\n5 D. 1 D. cyl., 60\u00c2\u00b0 left.\\nTwo days later a tenotomy of the right internal rectus\\nmuscle was done. With the glasses on, the eyes were per-\\nfectly straight. One month later there was a slight conver-\\ngent squint in the right eye, but not enough to notice, except\\non close inspection.\\nNo further operative procedure was deemed necessary.\\nGlasses were ordered to be worn continuously. The patient\\ndid not have single binocular vision.\\nCase XCIX. Marked convergent strabismus in each eye.,\\nmore pronounced in the right (50\u00c2\u00b0 right and 25\u00c2\u00b0 left) Poiver of\\nfixatiofi lost in the right, and m the left motion outward is limited\\nalso., the patient carrying her head to the left in order to see\\nstraight ahead: small amount of hyper metropia Cured by tenot-\\nomy of the internal recti muscles, and advancement of the right\\nexternal rectus. Violet J., aged four and one-half years, Avas\\nbrought to my clinic at the Post-Graduate School, in October,\\n1897, by her mother, to liave the child s eyes straightened,\\nbecause the children at the kindergarten made fun of her.\\nThe patient s eyes have both turned inward since she was a\\nbaby. At present the right eye turns far in (50\u00c2\u00b0) and cannot", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0295.jp2"}, "296": {"fulltext": "278\\nTHE REFRACTION OF THE EYE\\nbe turned out to the median line. The left eye turns inward\\n25\u00c2\u00b0, and motion outward is limited, so much that the patient\\ncarries her head to the left in order to see objects straight\\nahead. Fuchs, quoting Arlt, explains the oblique position of\\nthe head in such cases as follows As convergence is an\\nassociated movement of both interni, this impulse affects both\\nat once, so that, owing to their excessive contraction, the visual\\nlines would cross in front of the object but as the patient\\nthen w^ould fail to have direct vision of the object with either\\neye, he turns his head a little to one side. He thus gets the\\nobject into the line of vision, g^ of one, and that the better eye\\n(Z Fig. 102), Avhile the\\nline of vision, g\\\\ of the\\nother eye shoots off so\\nmuch the farther from\\nthe object. Thus the\\npatient secures fixation\\n5 with one eye at all\\nevents, although both\\ninterni are still strongly\\ncontracted. It is owning\\nto the last-named fact\\nthat the increase in the\\npower of adduction de-\\nvelops in the course of\\ntime in both eyes. By\\nthis fact, too, is explained the oblique position of the head in\\nthose affected with convergent strabismus such j)ersons car-\\nrying the head turned toward the side of the healthy eye.\\nThe right eye in the present case could not be made to fix\\nwhen the left was covered, the marked contraction of the\\ninternal recti preventing and, even with the left, the head\\nhad to be turned in order to fix the object.\\n1 Fuchs, Text-Book of Ophthalmology, p. 573.\\nFig. 102. (After Fuchs.) ShoTving oblique po-\\nsition of the eyes and head in convergent\\nstrabismus of both eyes.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0296.jp2"}, "297": {"fulltext": "ILLUSTRATIVE CASES 279\\nThe external movements of both eyes were not only limited\\nrelatively as compared to the internal movements, but actually,\\nas already remarked above.\\nOpMhalmometer Astigmatism with the rule, .50 D., 90\u00c2\u00b0\\nor 180\u00c2\u00b0 left eye. The right eye could not be measured\\nwith either the ophthalmometer or retinoscope, because the\\npatient could not turn the eye out far enough and to measure\\nthe left eye, the patient had to turn her head to the left in\\norder to give a front view of it.\\nOphthalmoscoi^e. H. 2D. in each eye.\\nAs the child did not know her letters, no subjective test\\nwas tried. Atropine was ordered, and after three days a\\nsecond test was made. The ophthalmometer gave the same\\nreading as before. The ophthalmoscope showed H. 2.50 D.\\neach. Ordered 2 D. sphere for each eye. I then did a te-\\nnotomy on each internal rectus. The eyes were not straightened\\nwith this, but I refrained from making an advancement of the\\nright external rectus at this time to see how much effect the\\ntenotomies would have. Atropine was used once a day for\\nthe next month, and the glasses were worn continuously. After\\nsix weeks the left eye was straight, but the right still turned\\nin considerably, 20\u00c2\u00b0, so a second tenotomy of the right internal\\nrectus, with advancement of the right external rectus, was\\ndone by my assistant. Dr. J. R. Nelson. The squint was over-\\ncorrected slightly, on purpose, and for the first few weeks after\\nthe operation it was noticeable, especially with the glasses on.\\nThe glasses were ordered discontinued. Six months after the\\nadvancement the eyes were perfectly straight, and the child\\nwas ordered to leave off the glasses.\\nThis patient was younger than I like to operate on for\\n1 The reason for taking the glasses off in this case is obvious. The squint\\nhaving been slightly over-corrected by the advancement, by taking oft the\\nglasses the patient had to use her accommodation, and this stimulated con-\\nvergence with the result that the eyes were held perfectly straight.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0297.jp2"}, "298": {"fulltext": "280 THE REFRACTION OF THE EYE\\nsquint, but as the strabismus was so pronounced and in each\\neye, and because she was an object of ridicule by her school\\ncompanions, I deemed it best to operate. At this writing,\\neighteen months after the advancement, the eyes are still\\nparallel, and the patient carries her head straight. She does\\nnot have single binocular vision, however, as the right eye is\\nvery amblyopic, as shown by tests with figures which the child\\nnow knows.\\nCase C. Divergent strabismus right eye; Antimetropia\\nCompound r}iyopie astigmatism right and compound hyperme-\\ntropic astigmatism left eye With glasses the squint ivas relieved\\nand single hinocidar vision obtained for distant vision^ hut not\\nfor near. June 7, 1897, Mrs. A. M., aged thirty-one years,\\nin good health, has always had trouble with her eyes, and when\\nshe reads or sews the eyes ache. The right eye has turned\\noutward at times for the last fifteen years.\\nOphthalmometer. Astigmatism with the rule, 2D., axis\\n80\u00c2\u00b0 4- or 170\u00c2\u00b0 right eye .50 D., axis 100\u00c2\u00b0 or 10\u00c2\u00b0 left eye.\\nTest cards and trial\\nK- I* W. 1 D. 1.50 D. cyl., 170\u00c2\u00b0.\\nL. V. 1^ :|-^W. .25D.+ .25 D. cyl., 100\u00c2\u00b0.\\nReads Jaeger No. 1 from 6 to 15 inches with the left eye.\\nThe patient does not use the eyes together for reading, either\\nwith or without the glasses. For distant vision with the glasses\\non the patient has single binocular vision, as shown by the test\\nwith prisms, to wit: ad. 10\u00c2\u00b0, ab. 7\u00c2\u00b0, sur. R. L. 2\u00c2\u00b0. Without\\nthe glasses she does not have single binocular vision.\\nOphthalmoscopic, \u00e2\u0080\u0094^l. 3 D. at 75\u00c2\u00b0 and M. 1 D. at 165\u00c2\u00b0 right\\neye H. 1 D. left eye.\\nBecause of a mild conjunctivitis alum was applied to the\\nlids and an astringent wash prescribed. One week later a\\nsecond test was made.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0298.jp2"}, "299": {"fulltext": "ILLUSTRATIVE CASES 281\\nSecond test Ophthalmometer. Astigmatism with the rule,\\n2.50 D., axis 75\u00c2\u00b0 or 165\u00c2\u00b0 right eye .75 D., axis 120\u00c2\u00b0 or\\n30\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nI^- 2^^ f* D. 2 D. cyl., 165\u00c2\u00b0.\\nL. V. f^ If W. .25 D. cyl., 120\u00c2\u00b0.\\nReads Jaeger No. 1 from 6 to 15 inches right, and Jaeger\\nNo. 1 from 4 to 10 inches left eye, but does not use the eyes\\ntogether. The angle alpha is small in the right eye, being 2\u00c2\u00b0\\npositive, while it is 4\u00c2\u00b0 positive in the left eye.\\nA third test agreed with the second, and .75 D. 2 D.\\ncyl., 165\u00c2\u00b0 right, and .25 D. cyl., 120\u00c2\u00b0 left, were ordered for\\nconstant wear. These glasses gave immediate relief from the\\nasthenopia from which the patient suffered. One year later I\\nsaw the patient again she was entirely comfortable, the eyes\\nwere straight, and she had single binocular vision for distance,\\nbut not for near ad. 15\u00c2\u00b0, ab. 6\u00c2\u00b0, sur. R. L. 2\u00c2\u00b0.\\nFor a very interesting case of convergent strabismus in the\\nmyopic eye of an antimetropic case, which was corrected by\\nglasses alone, see Case LXX in Chapter VI.\\nCase CI. Divergent strabismus right eye; Simple hyper-\\nmetropic astigmatism in both; Correction of refractive error;\\nTenotomy right external rectus; Relief. January 4, 1894,\\nHenrietta M., aged thirty-three years, in fairly good health,\\ngives the following history\\nFour years ago she had an abscess at the lower end of the\\nspine a year later had part of the coccyx removed, and six\\nmonths later some more of the coccyx removed. By these\\ntwo operations the spinal trouble was cured. In the mean-\\ntime, however, her eyes began to pain her when she did close\\nwork of any kind, and she had glasses fitted, which relieved\\nher for a time, but they do so no longer. She says if the", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0299.jp2"}, "300": {"fulltext": "282 THE REFRACTIOX OF THE EYE\\nright eye diverged at that time that the doctor did not tell\\nher of it. At the present time the right eye diverges between\\n6\u00c2\u00b0 and 10\u00c2\u00b0. She is wearing 75 D. cyl., 90\u00c2\u00b0 each.\\nOphthalmomete7\\\\ Astigmatism with the rule, 1.25 D.,\\naxis 90\u00c2\u00b0 or 180\u00c2\u00b0 each eye.\\nTest cards and trial\\nI\\nR. V. 1^ 10 _ w. .75 D. cyl., 90\u00c2\u00b0.\\nL. y. f^ ff W. .75 D. cyl., 90\u00c2\u00b0.\\nReads Jaeger No. 1 from 6 to 18 inches with the left eye,\\nand the same with the right if the left is covered. Angle\\nalpha equals 2\u00c2\u00b0 each eye, j)ositive.\\nOphthalmoscope. H. 1 D. at 90\u00c2\u00b0 and H. 2 D. at 180\u00c2\u00b0 each\\neye.\\nA second test resulted in the patient accepting the same\\nglasses as at first and since they corresponded exactly Avith\\nthe glasses she was already wearing, .75 D. cyl., 90\u00c2\u00b0 each, I\\ndid not change them neither did I put this patient under the\\ninfluence of a mydriatic, as is my custom in squint cases,\\nbecause the patient had a divergent squint with hypermetropia.\\nThe mydriatic would have increased the squint, as would also\\nthe plus spherical glass fitted under its influence. Since the\\ndivergent squint had apparently developed while she was\\nwearing the cjdindrical correction, and as she was a seamstress\\nand wanted relief from a diplopia which manifested itself fre-\\nquently in the last few weeks before coming to me, I advised\\nan operation, to which she consented. Accordingly, on Janu-\\nary 10, 1894, I did a complete tenotomy of the right external\\nrectus muscle, making a small opening in the conjunctiva and\\nTenon s capsule, but not dissecting back along the muscle and\\nup and down, as usual, as I did not want to have an over-\\neffect.\\nImmediately after the tenotomy, and for three or four days\\nfollowing, the right eye as measured by prisms converged 10\u00c2\u00b0.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0300.jp2"}, "301": {"fulltext": "ILLUSTRATIVE CASES 283\\nAt the end of two weeks, not only were the eyes perfectly\\nstraight and single binocular vision present, but the patient\\ncould use her eyes with perfect comfort.\\nJanuary 4, 1898, four years later, this patient came to me\\nagain complaining of headaches, pains in the eyes, and an\\noccasional diplopia, especially for near points. On examina-\\ntion, the right eye showed a divergence of perhaps as much as\\n5\u00c2\u00b0, but after covering and uncovering the eye several times\\nthe squint would disappear. I tested the eyes again and\\nfound an increase in the amount of the astigmatism. The\\nophthalmometer showed astigmatism with the rule, 2 D., 90\u00c2\u00b0\\nor 180\u00c2\u00b0 right, and 1.50 D., 90\u00c2\u00b0 or 180\u00c2\u00b0 left eye.\\nThe patient accepted 1.25 D. cyl., 90\u00c2\u00b0 right, and -f 1 D. cyl.,\\n90\u00c2\u00b0 left. It will thus be seen that the corneal astigmatism\\nliad increased .75 D. in the right eye, and .25 D. in the left.\\nThe patient by the subjective test accepted .50 D. more in the\\nright and .25 D. in the left, than four years previously, and\\nthe glasses were ordered. I gave her full doses of sulphate of\\nstrychnine also, and after about six weeks time the patient was\\nagain comfortable, and able to see and read. This was over a\\nyear ago, and at the present time the glasses enable her to do\\nher work with comfort. Single binocular vision is present.\\nCase CII. Divergent strabismus right eye; Myoina of high\\ndegree right and moderate degree left; Grlasses Tenotomy right\\nexternal rectus ivithout advancement of the internal rectus; Cure.\\nDecember 1, 1898, E. H., aged twenty, has been near-\\nsighted since a small child, was brought to me by her mother\\nto have her right eye straightened. She has pains in the eyes\\nat times. She is now wearing 5 D. spherical glass before\\neach eye. Not only does the right eye diverge about 20\u00c2\u00b0, but\\nthere is a slight horizontal nystagmus present. The patient is\\nextremel}^ nervous.\\nOphthalmometer. Astigmatism with the rule, .50 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0- right eye .75 D., axis 90\u00c2\u00b0 -f or 180^^- left eye.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0301.jp2"}, "302": {"fulltext": "284 THE REFRACTIOX OF THE EYE\\nTest cards and trial lenses.\\n200 30\\nReads Jaeger Xo. 1 at 10 inclies with tlie left eye.\\nOphthalmometer. Isl. 14 D. right eye, with a posterior\\nstaphyloma; M. 8 D. left eye.\\nSecond and third tests resulted in the patient accepting the\\nsame glasses as found at the first test. Ordered 9 D. right,\\nand 7 D. left. I did a complete tenotomy of the right\\nexternal rectus. AVith the aid of the glasses and the simple\\ntenotomy, the patient has perfectl} straight eyes, though not\\nsingle binocular vision. Usually these divergent squints, espe-\\ncially in m3 opic eyes, rec^uire advancement of the internal\\nrectus in addition to tenotomy of the external rectus. Four\\nmonths after operation, the patient still had straight eves.\\nCase CTII. Convergent strabismus right eye marked^ and to\\na moderate degree in the left Kyijermetropia right, compound\\nhypermetropic astigmatism left eye Glasses; Tenotomy of inter-\\nnal rectus of each eye Cure. December 1, 1898, M. H., aged\\nnineteen years, in good health, a sister of the patient just\\nreported above, with myopia and divergent squint in the right\\neye, was brought to me at the same time as her sister to have\\nher eye straightened. Her mother tells me that her eyes\\nhave turned since she was four years old, and attributes it to\\na scare.\\nIn connection with these two cases, it is an interesting\\netiological factor to know that the mother is antimetropic,\\nbeing higlily myopic in the right eye (13 D.), exactly the\\nsame as the myopia in right eye of the myopic daughter with\\ndivergent squint, and is slightly hypermetropic in the left eye,\\nabout .50 to 1 D. The father is hypermetropic, as is also a\\nyounger sister. Neither father or mother ever squinted, and", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0302.jp2"}, "303": {"fulltext": "ILLUSTEATIVE CASES 285\\nthe mother never wore glasses till forty-three years of age,\\nwhich I gave her for reading (see case, Chapter XI). The\\nquestion is: Did one daughter inherit one eye of the mother,\\nand the other daughter the other eye It is a striking coin-\\ncidence, to say the least. The report of the case of the sec-\\nond daughter is as follows\\nOphthalmometer. Astigmatism with the rule, .50 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 right eye astigmatism with the rule, .75 D.,^\\n90\u00c2\u00b0 or 180\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nR. V. =|-^:-|^W. 1.50D.\\nL. Y. 1^ 1^ W. 1 D. .25 D. cyl., 90\u00c2\u00b0.\\nReads Jaeger No. 1 from 6 to 20 inches with the left eye,\\nand at the same distance with the right, if the left is covered.\\nOphthalmoscojje. H. 2 D. right eye H. 1.50 D. left eye.\\nThere is a marked inward and upward squint of the right\\neye (about 20\u00c2\u00b0 in and 5\u00c2\u00b0 up), and a slight inward squint of the\\nleft eye, about 10\u00c2\u00b0. There has been a tenotomy of the left\\ninternal rectus some years ago, but the oculist refused to oper-\\nate on the right eye for fear of overeffect.\\nUnder atropine, this patient accepted .50 D. more sphere\\nthan when without it. I ordered -f 1.50 D. right and 1 D.\\n.25 D. cyl., 90\u00c2\u00b0, left eye, for constant wear. December T,\\nI made a complete and thorough tenotomy of the right internal\\nrectus. For the first few days there was a slight divergence.\\nGlasses were left off. After one week the eyes were straight\\nand the patient had single binocular vision. But after two\\nweeks time the left eye began to turn in. I ordered her to\\nwear the glasses again constantly, and, although the glasses\\nwere worn most of the time (the patient taking them off when\\nin the street, against my orders), and atropine (solution 4 gr. to\\n5 1) was instilled once a day iji each eye, it continued to squint.\\nAfter a month s use the mydriatic Avas discontinued. The left", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0303.jp2"}, "304": {"fulltext": "286 THE KEFRACTIOX OF THE EYE\\neve then turned inward 10\u00c2\u00b0, as it was before the operation on\\nthe right, the right now being the e}Te she fixed with and used.\\nFebruary 3, almost two months after the operation on the\\nright eye, I did a tenotomy of the left internal rectus. There\\nwas a decided diyergence immediately following, taking 15\u00c2\u00b0\\nprism, base in, to correct. This gradually diminished from\\nday to day, the glass being left off, till at the end of two\\nweeks it was entirely gone and the eye was perfectly straight.\\n_ The glasses were now ordered to be worn, but, after one\\nmonth, they were ordered discontinued permanently, as the\\nright eye had a tendency to diyerge if the patient got yery\\ntired or excited. I haye seen the patient within a few days\\n(nearly fiye months after the operation), and the eyes are per-\\nfectly straight, and binocular single A*ision is present, both for\\ndistance and near. With the stereoscope she can put the bird\\nin the cage, the rider on the horse, etc., with ease.\\nCase CIV. Divergent stralismus right eye; ^lyoina of\\nlarge araount each eye; Correction of myopia ivith glasses Tenot-\\nomy of right external rectus^ ivith advancement of right internal\\nrectus; Cif re. October 10, 1895, M. C, aged twenty-two\\nyears, has been near-sighted since a small child, but the right\\neye did not turn outward tmtil she was fourteen years old.\\nShe wore glasses for a while, but they did not help her much.\\nOphthalmometer. Astigmatism with the rule, .75 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 each eye, with slight irregular astigmatism\\neach.\\nTest cards and trial lenses.\\nR Y -1-4- -2iL \\\\v \u00e2\u0080\u0094ion\\n200 50\\nReads Jaeger No. 4 at 9 inches, with\u00e2\u0080\u0094 8 D. right and 6\\nD. left. Single binocular vision is absent.\\nOphthalmoscope. M. 13 D. right eye: 11 D. left eye.\\nThere is a posterior staph^doma in each eye. with choroidal", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0304.jp2"}, "305": {"fulltext": "ILLUSTKATIYE CASES 287\\nchanges in the right. Oblique illumination shows some very\\nfine opacities in the cornea in each eye. Test under atropine\\nresulted in the patient accepting the same glasses as when\\ntested without the mydriatic. Ordered, 12 D. right and\\n10 D. left for distant vision, and 8 D. right and 6 D.\\nleft for near vision.\\nOctober 17, I did a tenotomy of the right external rectus\\nand advancement of the right internal rectus. This operation\\nstraightened the eye, and for about four months while under\\nobservation it remained straight. Binocular single vision was\\nnot secured. This case is a representative one of a typical\\nclass of cases, that is, of myopia with divergent strabismus.\\nIn such cases, the squint usually develops between the ages of\\ntwelve and twenty-five years, and not in early childhood, as\\ndoes convergent strabismus. Glasses alone, as a rule, do not\\nrelieve it, and an operation must be resorted to in order to\\ncure it. Moreover, a simple tenotomy of the antagonist (ex-\\nternal rectus), of the weak muscle (internal rectus), or even\\ntenotomy of the associated antagonist (external rectus of the\\nopposite eye), in conjunction, does not, as a rule, relieve it. A\\ntenotomy of the external rectus and an advancement of the\\ninternal rectus of the squinting eye is the best procedure to\\nfollow, while the external rectus .of the non-squinting eye\\nshould not, as a rule, be operated upon.\\nCase CV. Periodic convergent strabismus at the age of\\nf orty -one following a fixed squint of childhood; Never had glasses\\nor operation; Simple hypermetropia Squint is non-comitant,\\nthough not paralytic Binocidar single vision for distance, hut not\\nfor near. March 1, 1898, Mary H., aged forty-one, came to\\nthe clinic of Drs. Lewis and Van Fleet for readino- o-lasses, and\\nwas assigned to me to test. She gives a history of squinting\\nat times with the left eye since a child. The left eye, when\\nshe was a young girl, turned in all the time, but she outgreAV\\nit, and it rarely turns in now only when excited or strain-", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0305.jp2"}, "306": {"fulltext": "288 THE REFEACTIOX OF THE EYE\\ning the eyes for close work. The eyes are perfectly straight\\nnow. In making the routine test for squint, the following\\npeculiarity in her case was brought out With the screen test,\\nfirst covering one eye and then the other, and having the,\\npatient look at a pencil held in front of her, it was discovered\\nthat when the amblyopic eye the left, the one that had\\nsquinted in childhood was covered, and the object fixed\\nwith the good eye (right), the left eye turned far in toward\\nthe nose. But, when the right or good eye was covered with\\na card, and the object fixed with the left eye, the right did not\\nsquint in or out, but remained directed toward the object, as\\nshown both by looking at it back of the card and by it remain-\\ning still and fixed on the object when uncovered. If the\\nobject was held at twenty feet, no turning of either eye took\\nplace when covered or uncovered. Furthermore, with both\\neyes uncovered, no turning of the left eye took place. It is\\nthe only case of the kind that has ever come under my obser-\\nvation, and I called the notice of Dr. Lewis and others to it.\\nOphthalmometer. Astigmatism with the rule, .50 D., axis\\n90\u00c2\u00b0+ or 180\u00c2\u00b0 -each eye.\\nTest cards and trial lenses.\\nM ff W. 1.50D.\\nL V -2-0- W 4- 3 D\\n200*100\\nReads Jaeger No. 1 from 8 to 16 inches, with plus .50 D.\\nadded to the distance glasses. Ordered 2 D. right and\\n3.50 D. left for reading. The patient has worn these glasses\\nfor more than eleven months with entire satisfaction. No\\ndistance glasses were given, as the patient did not feel the\\nneed of them and would not wear them. I had no desire to\\nhave her wear such glasses, since she had gone thus far in life\\nwithout them however, she should have had glasses fitted\\nwhen a child for constant wear. But no operation should have\\nbeen done, for very likely it would have resulted in a divergent", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0306.jp2"}, "307": {"fulltext": "ILLUSTRATIVE CASES 289\\nstrabismus, since she outgrew or got over the convergent\\nsquint without any aid whatever. The case emphasizes the\\npoint in a negative way that we should not be in too much of\\na hurry in operating on young children with convergent squint.\\nAnother case in point is the following.\\nCase CVI. Periodic convergent strabismus in cTiildJiood\\nrecovered from at the age of thirty-one without glasses or opera-\\ntion; Large amount of compound hypermetropic astigmatism in\\neach eye^ luith marked amblyopia in the left eye; Asihenoj)ia\\nRelief with glasses. February 3, 1899, Miss P. A. B., aged\\nthirty-one years, consulted me because of painful vision. After\\nshe reads for a while the eyes get tired, and she has to stop and\\ncover them for a few moments before she can go on again.\\nShe has never worn a glass, though when she was young the\\nleft eye turned in at times, but by voluntary effort on her part\\nshe could prevent the eye from turning. Her parents called\\nher attention to it at first, and she could feel it turn, but by\\nconstantly being reminded of it, and with persistent effort, she\\nprevented the eye from turning permanently. After reaching\\nthe age of twenty-five she had but little trouble to keep it\\nstraight, and now the eye does not turn at all unless under\\ngreat strain.\\nOphthalmometer. Astigmatism with the rule, 8 D., axis\\n45\u00c2\u00b0 H- or 135\u00c2\u00b0 right eye astigmatism against the rule, 3D.,\\naxis 135\u00c2\u00b0 or 45\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nR. V. -5;2_p_ 2^ w. 1.50 D. 3.25 D. cyh, 45\u00c2\u00b0.\\nL- V. ^2^ ^^%^Y. 3.50 D. 3.25 D. cyh, 135\u00c2\u00b0.\\nReads Jaeger No. 1 from 6 to 16 inches. She has single\\nbinocular vision. Ad. 12\u00c2\u00b0, ab. 3\u00c2\u00b0, sur. R. 5\u00c2\u00b0, L. 2\u00c2\u00b0.\\nOphthalmoscope.\u00e2\u0080\u0094 Yl.2.bOT at 45\u00c2\u00b0 and H. G D. at 135\u00c2\u00b0\\nright eye H. 4.50 D. at 135\u00c2\u00b0 and H. 8 D. at 45\u00c2\u00b0 left eye.\\nA second test agreed essentially Avith the lirst, and the", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0307.jp2"}, "308": {"fulltext": "290 THE REFRACTION^ OF THE EYE\\nglasses were ordered. The patient obtained immediate relief\\nfrom her asthenopia, the tendency of the left eye to turn\\ninward disappeared, and she could read without discomfort.\\nThe ophthalmometer in pointing out the slanting axes at\\nwhich the astigmatic glasses had to be worn in this case was of\\nthe greatest assistance, especially in the left or amblyopic eye.\\nIllustrative Cases of Muscular Insufficiency\\nIn this class of cases, extreme examples of which are for-\\ntunately rare, the object of prime importance in all of them is\\nan accurate fitting and adjustment of glasses. This procedure\\nalone, when accurately done, will relieve the great majority of\\ncases of muscular insufficiencies, especially if tonics are given,\\nand an outdoor exercise can be followed for a few hours each\\nday for a month or two.\\nIn the most severe cases, which finally develop into squint,\\nsometimes tenotomy of the muscles has to be done in order to\\nget relief from the deformity, just as in other cases of squint.\\nCase CVII. Insufficiency of the internal recti muscles;\\nsimple Jiypermetropia of small amount Asthenopia Correction\\nof refractive error Tonics Relief February 27, 1897, P. E. R.,\\naged thirty-four years, in good health, has complained for a\\nnumber of months of a dull and drowsy feeling, also that the\\neyes were weak and ran water when he used them much. He\\nhas a slight conjunctivitis, but not enough to cause his trouble.\\nOphthalmometer. Astigmatism with the rule, .50 D., axis\\n90\u00c2\u00b0 -t- or 180\u00c2\u00b0 each eye.\\nTest cards and trial lenses.\\nR. V. f^-:|^W. +.50D.\\nL. V. =|^-:|-^W. +.50D.\\nReads Jaeger No. 1 from 6 to 18 inches. Ad. 5\u00c2\u00b0, ab. 3\u00c2\u00b0,\\nsur. R. and L. 2\u00c2\u00b0.\\nOphthalmoscope. H. ID. in each eye.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0308.jp2"}, "309": {"fulltext": "ILLUSTRATIVE CASES 291\\nAn astringent wash was ordered for the conjunctivitis, and\\nstrychnine sulphate, gr. -g^Q-, as a tonic, three times a day.\\nTen days later a second test was made. The ophthalmom-\\neter and ophthalmoscope accorded with the first test, and the\\npatient accepted .50 D. sphere in each eye, as before. Ad. 7\u00c2\u00b0,\\nab. 3\u00c2\u00b0, sur. R. and L. 2\u00c2\u00b0. Ordered .50 D. sphere for reading\\nand the eye wash and strychnine were continued.\\nWithin six weeks time this patient was entirely free from\\nhis asthenopic symptoms, the muscle insufficiency had dis-\\nappeared, and the patient was comfortable. After two months\\ntreatment I ordered the strychnine stopped, but advised a little\\noutdoor exercise each day. It is now over two years since I\\nfirst saw him, and he remains free from eye trouble. If he\\nfeels run down at any time I have him take the tonic of\\nstrychnine for four to six weeks, but this has been necessary\\nbut twice during the period stated.\\nCase CVIII. Marked msufficieney of the internal recti;\\nSimple liypermetropia of moderate amount Asthenopia; Correc-\\ntion of the refractive error; Tonics; Relief. April 17, 1897,\\nMiss L. W. P., aged twenty-one years, in fairly good health,\\nbut is hard worked as a stenographer. She has at times had\\nattacks, in which she would lose consciousness, and during*\\nsome of these attacks would have involuntary movements of\\nthe bowels and bladder, but never bit her tongue. She is\\nrather nervous. She has worn glasses for two and one-half\\nyears, but they have not been satisfactory. There is great\\nblurring of images at times, and much pain in the eyes and\\nhead after using the eyes for a long while.\\nOphthalmometer. Astigmatism with the rule, .50 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 each eye.\\nTest cards and t7 ial lenses.\\nR.V. |^:fJW. -f-l.oOD.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0309.jp2"}, "310": {"fulltext": "292 THE REFPxACTIOX OF THE EYE\\nReads Jaeger Xo. 1 from 6 to 18 inches.\\nOiyJitlial mo scope. H. 2 D. each. Ad. 6\u00c2\u00b0, ab. 7\u00c2\u00b0, sur. R.\\nand L. 2\u00c2\u00b0. Ordered strychnine sulphate, gr. -g^j. three times\\na day. Three days later the patient accepted exactly the same\\nglasses as at the first test, and they were ordered. The ad. was\\n7\u00c2\u00b0, ab. 7\u00c2\u00b0, sur. R. and L. 2\u00c2\u00b0. At the end of one week the patient\\nwas perfectly comfortable, and in two weeks the muscle test\\nwas as follows ad. 9^ ab. 7\u00c2\u00b0, sur. R. and L. 2\u00c2\u00b0. In four\\nweeks: ad. 12\u00c2\u00b0, ab. 7\u00c2\u00b0, sur. R. and L. 2 After two months the\\nstrychnine was stopped. These glasses were worn with com-\\nfort until December, 1898, almost two years, when she returned,\\ncomplaining of pain in the left eye. On testing the patient s\\neyes the following conditions were found\\nOphthalmometer. Astigmatism with the rule, .50 D., axis\\n45\u00c2\u00b0 or 135\u00c2\u00b0 right eye; astigmatism against the rule, .50\\nD., 135\u00c2\u00b0 or 45\u00c2\u00b0 left eye.\\nTe8t cards and tried lenses.\\nR. V. |A _ 14 +2 D. 4- .25 D. cyl., 45\u00c2\u00b0.\\nL. V. y ff W. 1.75 D. 4- .25 D. cyL, 135\u00c2\u00b0.\\nReads Jaeger Xo. 1 from 6 to 18 inches.\\nOphthalmoscope. H. 2D. each. Ad. 7\u00c2\u00b0, ab. 7\u00c2\u00b0, siu\\\\ R.\\nand L. 1\u00c2\u00b0.\\nThree days later a second test was made, the patient\\naccepted the same glasses, and they were ordered. Str^xhnine\\nsulphate, gr. gL, was ordered to be taken three times a day for\\na few weeks. It has been four months since these last glasses\\nwere ordered the patient, whom I see from time to time,\\ntells me she is without any pain at all, and can work for long\\nhours.\\nThe patient has had none of her attacks since being\\nTinder my care.\\nThe other interesting feature in this case to me. besides the", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0310.jp2"}, "311": {"fulltext": "ILLUSTRATIVE CASES 293\\ninsufficiency of the muscles, was the change in the shape of the\\ncornea. When I first saw her, the ophthalmometer showed\\nastigmatism with the rule, .50 D., axis 90\u00c2\u00b0 or 180\u00c2\u00b0 The\\npatient accepted no cylindrical glass. About two years later\\nthe instrument showed astigmatism of .50 D., but the axis was\\nat 45\u00c2\u00b0 in the right eye and at 135\u00c2\u00b0 in the left. This was a\\nchange in the axis of 45\u00c2\u00b0 in each eye. Furthermore, the\\npatient accepted .25 D. cyl., 45\u00c2\u00b0 right, and .25 D. cyl.,\\n135\u00c2\u00b0 left, in addition to the spherical glass.\\nIn this case, when I first saw her, the abduction actually\\nexceeded the adduction yet, with a proper correction of the\\nrefractive error, and by the aid of tonics, the patient was not\\nonly able to pursue her work with comfort, but was cured of\\nwhat appeared to be petit mal.\\nCase CIX. Insufficiency of the internal recti muscles\\nSimple hypermetropic astigmatism; Asthenopia; Correction of\\nthe refractive error Relief. October 7, 1893, K. E. H., aged-\\ntwenty-one years, student, never very strong, has been troubled\\nwith his eyes since about twelve years of age. Was fitted to\\nglasses in the Manhattan Eye and Ear Hospital, when seven\\nyears of age, and was given 1 D. sphere combined with 1\u00c2\u00b0\\nprism, base in, for each eye for reading. These glasses helped\\nhim very much the first year, but have not been comfortable\\nsince then, though they were much better than no glasses. He\\ncomes to the clinic again on account of pains in the eyes and\\nheadaches.\\nOphthalmometer. Astigmatism with the rule, 1 D., axis\\n90\u00c2\u00b0 H- or 180\u00c2\u00b0 right eye 1.25 D., axis 90\u00c2\u00b0 -j- or 180\u00c2\u00b0 left\\neye.\\nTest cards and trial lenses.\\nR. V. f f w. .50 D. cyl., 90\u00c2\u00b0.\\nL- V. ff |g W. .75 D. cyl., 90\u00c2\u00b0.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0311.jp2"}, "312": {"fulltext": "294 THE REFRACTION OF THE EYE\\nReads Jaeger No. 1 from 4 to 20 inches. Ad. 10\u00c2\u00b0, ab. 8\u00c2\u00b0,\\nsur. R. and L. 2\u00c2\u00b0.\\nOphthalmoscope. B.. .50 D. at 90\u00c2\u00b0 and H. 1 D. at 180\u00c2\u00b0\\neach.\\nA second test, made very carefully as to the astigmatism,\\nresulted in the patient accepting the same glasses exactly as at\\nthe first test. They were ordered. The patient reported at\\nthe clinic weekly, for several weeks, as I wished to see if the\\nsimple cylinders would relieve him entirely. He said that\\nthey gave him relief from the pain in th6 eyes and his head-\\naches, and were much more comfortable than the spherical\\nglasses and prisms. The internal recti gained in strength also,\\nwhile the external remained as they were at first.\\nCase CX. Insufficiency of all the recti muscles Relatively^\\nthe external recti were weaker than the others^ as an homonymous\\ndiplopia was present at times Compound hypermetropic astigma-\\ntism Correction of refractive error Tonics Relief. Novem-\\nber 20, 1894, Sadie G., aged fourteen years, in good health,\\ncame to the clinic of Drs. Lewis and Van Fleet, and was\\nassigned to me for examination. She complains of seeing\\ndouble at times, but otherwise has had very little trouble with\\nher eyes. For the last few weeks the lids have been somewhat\\ninflamed, and stick together in the morning.\\nOphthalmometer. Astigmatism with the rule, 1 D., axis\\n90\u00c2\u00b0 -f or 180\u00c2\u00b0 each eye.\\nTest cards and trial lenses.\\nR. V. f\u00c2\u00a7 fl- W. .50 D. cyl., 90\u00c2\u00b0.\\nL. V. 1^ ff W. -h .50 D. cyl., 90\u00c2\u00b0.\\nReads Jaeger No. 1 from 5 to 15 inches. A 1\u00c2\u00b0 prism gives\\ndiplopia in every direction, and over whatever muscle the apex\\nis placed. The fact, however, that the patient has occasional", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0312.jp2"}, "313": {"fulltext": "ILLUSTRATIVE CASES 295\\nhomonymous diplopia, especially when looking at near objects,\\nwould indicate a relative weakness of the external recti\\nmuscles.\\nOphthalmoscope, H. .50 D. at 90\u00c2\u00b0 and H. 1 D. at 180\u00c2\u00b0 in\\neach eye.\\nA mild astringent wash was ordered for the lids and strych-\\nnine sulphate, gr. g^^ three times a day, as a tonic.\\nOne week later, a second test was made. The ophthal-\\nmometer and ophthalmoscope gave the same results as at the\\nfirst test, and the patient again accepted simple cylindrical\\nglasses, which were ordered.\\nThe muscles were in exactly the same condition as the\\nweek previous. The patient was instructed to wear the\\nglasses constantly, to continue the tonic of strychnine, to take\\nsome outdoor exercise, and to report in one month. At the\\nend of a month the patient had no dij)lopia, eyes comfortable,\\nand she was feeling much better in every way. Ad. 4\u00c2\u00b0, ab. 1\u00c2\u00b0,\\nsur. R. and L. 1\u00c2\u00b0. The patient was ordered to report if the\\neyes troubled her again, but has not been seen since then.\\nCase CXI. Insufficiency of all of the recti muscles Trouble-\\nsome homonymous diplopia; Compound hypermetropic astigma-\\ntism; Asthenopia; Dizziness; Correction of refractive error Tonic\\ngiven, and less work ordered Relief. December 26, 1893, Miss\\nB. C, aged thirteen years, came to the clinic of Drs. Lewis\\nand Van Fleet, complaining of dizziness and of seeing double\\nat times. The patient has always enjoyed good health, and her\\nfather and mother are living and in good health. She has one\\nbrother and three sisters, all younger than herself, and with no\\neye troubles of any kind. The patient is very studious, goes\\nto school during the day and studies till eleven o clock at\\nnight, besides doing outside reading.\\nOphthalmometer. Astigmatism with the rule, 2 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 right eye 2.75 D., axis 90\u00c2\u00b0 or 180\u00c2\u00b0 left\\neye.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0313.jp2"}, "314": {"fulltext": "296 THE REFRACTION OF THE EYE\\nTest cards and trial lenses.\\nR. V. f^ 1^ W. 1.25 D. cyl., 90\u00c2\u00b0.\\nL-^-=A o=MW. 2 D. cyl., 90\u00c2\u00b0.\\nHeads Jaeger No. 1 from 6 to 14 inches. A 1\u00c2\u00b0 prism gives\\ndiplopia in all directions, that is, when the apex is placed over\\nany one of the recti mnscles it causes diplopia.\\nThe diplopia that the patient complains of, and which can\\nbe produced at will by putting a red glass in front of one eye,\\nis homonymous most of the time, but occasionally is crossed,\\nespecially when the patient first looks at near objects.\\nOphthalmoscope.\u00e2\u0080\u0094 li, 1 D. at 90\u00c2\u00b0 and H. 3 D. at 180\u00c2\u00b0\\nright eye H. 2 D. at 90\u00c2\u00b0 and H. 4 D. at 180\u00c2\u00b0 left eye.\\nOrdered strychnine sulphate, gr. gL.^ taken three times a\\nday, and to do less work with the eyes also an hour s walk\\neach day. Four days later a second test was made.\\nOphthalmometer. Astigmatism with the rule, 1.75 D.,\\naxis 90\u00c2\u00b0 or 180 right eye 2.50 D., axis 90\u00c2\u00b0 or 180\u00c2\u00b0\\nleft eye.\\nTest cards and trial lenses.\\nR. V. 1^ W. 15 D. 4- 1.25 D. cyl., 90\u00c2\u00b0.\\nL. V. 1^ 1^ W. 75 D. 2 D. cyl., 90\u00c2\u00b0.\\nReads Jaeger No. 1 from 6 to 15 inches. The ophthal-\\nmoscope showed the same condition as at the first test. A\\nthird test, two days later, resulted in the patient accepting\\nthe same glass as that accepted on the second, and the glasses\\nwere ordered for constant wear the tonic was continued,\\nand the patient admonished not to use the eyes to the point\\nof abuse as she had been doing.\\nAn immediate effect of the glasses was the relief of the\\ndiplopia and dizziness. If she took the glasses off, diplopia\\nwould manifest itself, but while she kept them on she had\\nrelief.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0314.jp2"}, "315": {"fulltext": "ILLUSTRATIVE CASES 297\\nThese two cases just reported show that muscular insuffi-\\nciency of marked degree, and even when attended with occa-\\nsional diplopia, may be relieved by glasses and tonics, without\\noperative interference. Sometimes, however, it will not yield\\nto this simple procedure, and an operation has to be resorted\\nto, as shown by the following case.\\nCase CXII. Insufficiency of the internal recti; Simple\\nhypermetropic astigmatism Occasional crossed diplopia Dizzi-\\nness Marked asthenopia; Correction of refractive error and\\ntonics without relief Prisms added to glasses without reliefs hut\\nwith the development of divergent squint; Operation; Relief.\\nMiss Celia L., aged twenty years, in good health, consulted me\\nfirst on September 12, 1893, on account of pains in the eyes,\\nheadaches, dizziness, and because she saw double occasionally.\\nShe was fitted with glasses two years ago, which were com-\\nfortable until she began to sew on fine work about two months\\nago.\\nOphthalmometer. Astigmatism with the rule, 2.75 D.,\\naxis 120\u00c2\u00b0 or 30\u00c2\u00b0 right eye 2.75 D., axis 90\u00c2\u00b0 or 180\u00c2\u00b0\\nleft eye.\\nTest cards and trial lenses.\\nR. y. 2^ 20 ^y. _|. 2.25 D. cyl., 120\u00c2\u00b0.\\nL. V. 1^ 1^ W. 2.25 D. cyl., 90\u00c2\u00b0.\\nReads Jaeger No. 1 from 6 to 18 inches. Ad. 5\u00c2\u00b0, ab. 7\u00c2\u00b0,\\nsur. R. and L. 1\u00c2\u00b0.\\nOphthalmoscope. \u00e2\u0080\u0094^m. at 120\u00c2\u00b0 and H. 2 D. at 30\u00c2\u00b0 right\\neye Em. at 90\u00c2\u00b0 and H. 2 D. at 180\u00c2\u00b0 left eye.\\nThe patient has been wearing for a year 2 D. cyl., 120\u00c2\u00b0,\\nright, and 2 D. cyl., 80\u00c2\u00b0, left; and these glasses give her\\nabout as good vision as the glasses she now accepts. Ordered\\ntonic of strychnine, and a mild astringent wash, for a slight\\nconjunctivitis that is present.\\nThree weeks later the patient returned, not improved, but", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0315.jp2"}, "316": {"fulltext": "298 THE EEFRACTION OF THE EYE\\nworse as regards tlie insufficiency. The glasses could not be\\nimproved upon: ad. 1\u00c2\u00b0, ab. 9\u00c2\u00b0, sur. R. and L. 2\u00c2\u00b0. She has\\ngreat pain in using the eyes, and the diplopia is more trouble-\\nsome than ever. With a red glass in front of one e^ e, the\\ndiplopia is constant, vertical, and crossed. Prism 1\u00c2\u00b0, base\\ndown, and prism 5\u00c2\u00b0, base inward, in front of left eye, corrects\\nsame. These prisms, divided between the two eyes, were\\nadded to her glasses, and for four months she was very com-\\nfortable but, on February 14, 1894, she returned, complain-\\ning of her old symptoms, especially of the diplopia, which was\\nconstant. A divergent strabismus of between 5\u00c2\u00b0 and 10\u00c2\u00b0 was\\npresent in the right eye.\\nAn operation was advised and performed a complete tenot-\\nomy of the right external rectus nluscle. A very small opening\\nwas made in the conjunctiva, and then in the capsule of Tenon,\\nbeing careful not to dissect up the capsule to any great extent,\\nbut just enough to pick up the tendon of the muscle, which\\nwas divided completely.\\nAt first there was over-correction, the eye turning inward\\ntoo far by 15\u00c2\u00b0, as shown by the prism which it took to correct\\na homonymous diplopia. Ordered to wear her glasses without\\nprisms. In one month s time the eyes were perfectly straight,\\nad. 15\u00c2\u00b0, ab. 6\u00c2\u00b0, sur. R. and L. 2\u00c2\u00b0, single binocular vision.\\nThe patient was entirely comfortable, and able to pursue her\\nvocation as a seamstress.\\nThe angle alpha in this case was positive, but very narrow,\\n2\u00c2\u00b0 and this may, in a measure, account for the insufficiency\\nof the internal recti muscles, developing into a divergent stra-\\nbismus.\\nThis patient is still under observation, and she is comfort-\\nable. The following case is similar to the present one, but no\\nprism was tried before the operation was done.\\nCase CXIII. Insufficiency of the internal recti muscles\\nOccasional diplopia for the near point Hypermetropia of small", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0316.jp2"}, "317": {"fulltext": "ILLUSTRATIVE CASES 299\\namount^ with slight astigmatism in the left eye Marked astheno-\\npia Glasses^ tonics^ prism exercises^ open-air exercises^ and rest^\\nall fail to relieve Tenotomy of the right external rectus^ followed\\nin two and one-half years with tenotomy of the left external rectus^\\neffect a cure. June 1, 1896, C. H. M., aged seventeen years,\\nin only fairly good health his vitality is much reduced on\\naccount of long hours of study and sexual excesses. He has\\npassed through many hands, sixteen in all, has v7orn\\nglasses and taken tonics, but without relief from headaches and\\npains in the eyes, of which he complains. The headaches are\\npresent even in the morning, and are intensified by using the\\neyes. Print doubles after using the eyes for a little while. If\\nhe cannot get relief, he says he must give up his studies. He\\ncomes from a healthy family, and none of them, except himself,\\nare troubled with their eyes.\\nOphthalmometer. Astigmatism with the rule, .50 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 each eye.\\nTest cards and trial lenses.\\nL- V. 1-2- |o _ w. .25 D. cyl., 90\u00c2\u00b0.\\nReads Jaeger No. 1 from 6 to 15 inches. Ad. 10\u00c2\u00b0, ab. 9\u00c2\u00b0,\\nsur. R. and L. 3\u00c2\u00b0.\\nOphthalmoscope. H. 1.50 D. each eye.\\nOrdered strychnine sulphate, gr. -gL, three times a day, the\\npatient to study less, to desist from his excesses, and to take\\nmore outdoor exercise. He has been riding the bic3Tle con-\\nsiderably already.\\nThree days later, a second test was made, and but little\\nchange in the condition of the eyes was found. Ordered\\n.50 D. right, and .25 D. cyl., 90\u00c2\u00b0, left, to be worn con-\\nstantly, and the other treatment continued. Ten days later,\\nthe eyes not improving, the strychnine was increased to gT. ^V,\\nthree times a day, the patient being cautioned as to the physio-", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0317.jp2"}, "318": {"fulltext": "300 THE REFRACTION OF THE EYE\\nlogical effect of tlie strychnine. Prism exercises were ordered\\nin addition to other treatment, although I have little faith in\\nsuch exercises, and would not now advise them.\\nSix weeks later, the patient getting no better, but worse,\\nad. 9\u00c2\u00b0, ab. 10\u00c2\u00b0, sur. R. and L. 3\u00c2\u00b0, I advised tenotomy of the\\nright external rectus, and this was performed August 14. Ho-\\nmonymous diplopia immediately following, from over-correc-\\ntion, required prism 10\u00c2\u00b0, base out, to correct. Eleven days\\nlater, the diplopia disappeared, ad. 16\u00c2\u00b0, ab. 4\u00c2\u00b0, sur. R. and L. 2\u00c2\u00b0.\\nSeptember 21, ad. 14\u00c2\u00b0, ab. 6\u00c2\u00b0, sur. R. and L. 2\u00c2\u00b0, eyes perfectly\\ncomfortable, and he resumed his studies.\\nFebruary 16, 1897. He has trouble again with his eyes,\\nfrom too close application to studies and from sexual excesses.\\nTonics and rest relieved him.\\nJanuary 4, 1898. Patient returns, complaining that he\\ndoes not feel well, has had some trouble with his heart, head-\\naches, general lassitude, and eyes suffer, with general depressed\\ncondition. He continues to dissipate from time to time. His\\nold glasses cannot be improved upon. The vision in each eye\\n|-a ad. 10\u00c2\u00b0, ab. 8\u00c2\u00b0, sur. R. and L. 2\u00c2\u00b0. I told the patient I\\ncould do no more for him unless he obeyed instructions and\\nstopped dissipating. He went to another oculist, who put him\\nunder a mydriatic, and gave him 1.50 D. each eye, full cor-\\nrection. These glasses did not give him relief. The adduc-\\ntion was already too weak, and to put full correction of his\\nhypermetropia on him simply made it weaker and when he\\ncame to me again, on December 20, 1898, he was complaining\\nof diplopia, much headache, and pains in the eyes. Ad. 8\u00c2\u00b0,\\nab. 9\u00c2\u00b0, sur. R. and L. 2\u00c2\u00b0. Advised and performed a tenotomy\\nof the left external rectus. A decided convergence followed,\\nrequiring prism 20\u00c2\u00b0, base out, to correct it. Glasses were left\\noff. The convergence gradually diminished, as it had after\\nthe operation on the right eye and, by January 25, 1899,\\nabout five weeks, parallelism existed; ad. 20, ab. 2\u00c2\u00b0, sur. R.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0318.jp2"}, "319": {"fulltext": "ILLUSTRATIVE CASES 301\\nand L. 2\u00c2\u00b0. February 10, ad. 16\u00c2\u00b0, ab. 5\u00c2\u00b0, sur. R. and L. 2\u00c2\u00b0.\\nThe patient is perfectly comfortable, and able to use the first\\nglasses given him.\\nIt has been five months since the last operation the patient\\nhas no asthenopia, is comfortable, and in school.\\nCase CXIV. Insufficiency of the internal recti; Asthenopia;\\n^Photophobia Neuralgia Emmetropia Reading glasses ordered;\\nTonics Improvement in the eyes^ hut not entire relief from asthe-\\nnopic symptoms. March 25, 1898, Miss F. M., aged forty-three\\nyears, in delicate health, complains that her eyes have troubled\\nher for a year. She thinks it has something to do with an\\novarian neuralgia (right side) from which she has suffered for\\nthe last year. The pain begins in the eyes first, as a rule, but\\noften it is just the reverse. She has severe headaches, especially\\nin the back part of her head.\\nFor the last three weeks she has suffered greatly from severe\\npain in the eyes and from photophobia, and has been compelled\\nto wear blue glasses to keep the light out of her eyes.\\nOphthalmometer. Astigmatism with the rule, .50 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 each eye.\\nTest cards and trial\\nR. V. 1^ -f not improved.\\nL. y. 1^ not improved.\\nReads Jaeger No. 1 from 8 to 20 inches, with .50 D.\\nAd. 10\u00c2\u00b0, ab. 8\u00c2\u00b0, sur. R. and L. 2\u00c2\u00b0.\\nOphthalmoscope. Emmetropia each. Some congestion of\\nthe fundus in each eye, but no lesion.\\nOrdered .50 D. for each eye for reading. Under a tonic\\nof strychnine and arsenic, general hygiene and rest, she was\\nmuch improved in general health and her ovarian neuralgia\\nand also the asthenopia and photophobia were helped, but not\\nentirely relieved. However, she would have periods when all", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0319.jp2"}, "320": {"fulltext": "302 THE REFRACTION OF THE EYE\\nof her old symptoms would reappear. Her adduction was in-\\ncreased to 14\u00c2\u00b0, while ab. and sur. remained as before.\\nIn such a case as this it would have been futile to cut\\nthe ocular muscles, for the asthenopia and ovarian trouble\\nwere likely both due to a common cause. At any rate, when\\nshe was feeling well, generally, the eyes gave her little or no\\ntrouble, indicating clearly that the eye trouble was not local,\\nbut due to a general debility.\\nCase CXV. Insufficie7icy of the internal recti; Small amount\\nof hyper metropia Presbyopia; Asthenopia; Correction for near\\nwork; Tonics; Exercise; Relief. December 29, 1896, C. H.,\\nEsq., aged fifty years, in good health, but uses his eyes ex-\\ncessively. He complains of pain in the eyes and of redness of\\nthe lids after using the eyes in the evening. He has had\\nrheumatism in mild attacks for the last few years.\\nOphthalmometer. Astigmatism with the rule, .50 D., axis\\n90\u00c2\u00b0 -f or 180\u00c2\u00b0 both.\\nTest cards and trial lenses.\\nR. V. W. .50D.\\nI-V. =fM^+W. .50D.\\nReads Jaeger No. 1 from 8 to 24 inches, with 3 D. sphere.\\nAd. 10\u00c2\u00b0, ab. 8\u00c2\u00b0, sur. R. and L. 2\u00c2\u00b0.\\nOphthalmoscope. H. .50 D. each eye.\\nOne day later, a second test was made, and the patient\\naccepted the same glasses as at the first test. Ordered 3 D.\\neach eye for reading. Also ordered a tonic of strychnine and\\nopen-air exercise. After three months treatment, adduction 15\u00c2\u00b0,\\nab. 7\u00c2\u00b0, sur. R. and L. 3\u00c2\u00b0. The patient is entirely comfortable\\nand able to use his eyes for long hours. The strychnine was\\nstopped. I saw this patient a year later, and again two years\\nlater. He accepted no increase in presbyoj^ic glass ad. 14\u00c2\u00b0,^\\nab. 6\u00c2\u00b0, sur. R. and L. 2\u00c2\u00b0; was still entirely comfortable, but\\nas he was passing through the city, stopped to let me see him.\\ni", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0320.jp2"}, "321": {"fulltext": "ILLUSTRATIVE CASES 303\\nCase CXVI. Insufficiency of the internal recti; Mixed\\nastigmatism in one eye^ and compound hypermetropic astigma-\\ntism in the other; Occasional diplopia at the near point; Severe\\nheadaches Has had a number of graduated tenotomies Correc-\\ntion of refractive error; Tonics; Relief. January 9, 1894,\\nW. J. C, aged twenty years, in fairly good health, a close\\nstudent, consulted me on account of severe headaches, and\\nbecause he saw double for near work after using the eyes for\\nany considerable time. He is one of the unfortunates who has\\nbeen subjected to several, he does not know just how many,\\ngraduated tenotomies. From moderate headaches and no\\ndiplopia before the operations, he now has very severe head-\\naches and frequently diplopia for the near point.\\nOphthalmometer. Astigmatism with the rule, .50 D., axis\\n105\u00c2\u00b0 or 15\u00c2\u00b0 right eye with the rule, 2.25 D., axis 105\u00c2\u00b0\\nor 15\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nI* ff W. -f- .25 D. cyl., 105\u00c2\u00b0.\\nL. V. J^ 1^ W. 1.25 D. cyl., 105\u00c2\u00b0 .75 D. cyl., 15\u00c2\u00b0.\\nReads Jaeger No. 1 from 4 to 15 inches. Ad. 2\u00c2\u00b0, ab. 6\u00c2\u00b0,\\nsur. R. and L. 1\u00c2\u00b0.\\nOphthalmoscope. H. .50 D. right eye; H. 1 D. at 15\u00c2\u00b0\\nand M. 1 D. at 105\u00c2\u00b0 left eye.\\nOrdered strychnine sulphate in increasing doses, and rest\\nand exercise for a few days.\\nSecond test the ophthalmometer gave the same readings\\nas at the first test.\\nTest cards and trial lenses,\\nR. V. =||:ffW. .25 D. cyl., 105\u00c2\u00b0.,\\nL. V. 1^ |g W. 1 D. cyl., 105\u00c2\u00b0 .50 D. cyl., 15\u00c2\u00b0.\\nReads Jaeger No. 1 from 4 to 17 inches. Ad. 4\u00c2\u00b0, ab. G\u00c2\u00b0,\\nsur. R. and L. 2\u00c2\u00b0.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0321.jp2"}, "322": {"fulltext": "304 THE REFRACTION OF THE EYE\\nOn a tliird test, the patient accepted exactly the same\\nglasses as at the second, and they were ordered. The strych-\\nnine, gr. g^Q, was given three times a day, and the patient\\ndirected to take some outdoor exercise each day. Within\\nthree weeks time this patient s adduction exceeded his abduc-\\ntion (ad. 7\u00c2\u00b0, ah. 6\u00c2\u00b0), his headaches and diplopia were gone, and\\nhe was able to use his eyes with comfort. The strychnine was\\ncontinued for two months, when adduction was 10\u00c2\u00b0, ab. 6\u00c2\u00b0, and\\nsur. R. and L. 2\u00c2\u00b0.\\nMay 2, 1896, over two years after I first saw him, the\\npatient returned with headaches and pains in the eyes. On\\ninquiring, I found that he had broken the right glass, and had\\na new one put in without an order. On examination, I found\\nthe optician had put a cylinder in the right eye, axis at 75\u00c2\u00b0,\\ninstead of 105\u00c2\u00b0, as it should have been. The refraction had\\nchanged slightly in the left eye, the patient now accepting\\n-f- .75 D. cyl., 105\u00c2\u00b0- 1 D. cyL, 15\u00c2\u00b0. Ad. 7\u00c2\u00b0, ab. 7\u00c2\u00b0, sur. R.\\nand L. 2\u00c2\u00b0.\\nI again placed the patient on a tonic of strychnine, gr.\\nthree times a day, for two months. I have heard from this\\ngentleman, from time to time, for two years after this last\\nexamination, and though at times, when very hard worked or\\nnot feeling well, he has some pain in the eyes, he has no diplo-\\npia, and, as a rule, is comfortable, and can pursue his calling as\\na minister.\\nCase CXVII. Insufficiency of the interyial recti; Occasional\\ndiplopia; Asthenopia Hypermetropia and Presbyopia; Reading\\nglasses; Tonics; Relief. November 26, 1896, Dr. D. L. H.,\\naged forty-three years, in good health, has worn glasses for the\\nlast eighteen years. He complains of late that when he uses\\nthe eyes for any considerable time he gets pains in the back of\\nthe head and in the eyes.\\nOphthalmometer. Astigmatism with the rule, .50 D., 90\u00c2\u00b0\\n-f- 180\u00c2\u00b0- right eye with the rule, .25 D., 90\u00c2\u00b0 180\u00c2\u00b0- left eye.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0322.jp2"}, "323": {"fulltext": "ILLUSTRATIVE CASES 305\\nTest cards and trial lenses.\\nU f f W. 75 D.\\nL. y. 1^ f f W. 75 D.\\nReads Jaeger No. 1 from 8 to 16 inches, with 1.50 D.\\nsphere in each. Ad. 10\u00c2\u00b0, ab. 9\u00c2\u00b0, sur. R. and L. 3\u00c2\u00b0. If the\\npatient does not fix his attention closely on objects, one eye\\nwill at times diverge but by effort he can overcome this.\\nOrdered 1.50 D. sphere, each eye, for reading, but discon-\\ntinued his distance glasses. Strychnine was given in increas-\\ning doses till physiological effect was obtained. The patient\\ngot almost immediate relief. I wrote to the doctor two years\\nlater for a report of his case, and his reply is here given.\\nDear Doctor Davis,\\nYours, relative to the condition of my eyes, is received. My eyes re-\\nmained about the same for another year, when, on account of increased irrita-\\nbility, I increased strength of glass from 1.50 D. to 1.75 D., which gives me\\nabsolute relief to the present time. rr,,\\nThankmg you, etc.,\\nD. L. H.\\nThe muscular insufficiency in this case was so marked that\\na periodical squint was present yet, with the correct glass for\\nreading and tonics, he was cured.\\nCase CXYIII. Insufficiency of the internal recti made\\nworse hy wearing strong prisms^ bases in; Incapacitated for work\\non account of the great pain m the eyes and head; Compound\\nmyopic astigmatism; Mild trachoma; By taking off the prisms\\nand giving the proper glasses^ the patient got entire relief., and was\\nable to resume his professional callirig, that of a lawyer. Octo-\\nber 1, 1898, H. A. T., Esq., aged thirty-six, in good health,\\nexcept for his eyes, which have given him trouble for the last\\neighteen years. Has had a more or less severe inflammation of\\nthe lids for that time. His chief trouble, however, has been", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0323.jp2"}, "324": {"fulltext": "306 THE REFKACTIOIs^ OF THE EYE\\nfrom a weakness of the eyes and inability to use them for any\\nconsiderable length of time without great pain in them and\\nsevere headaches. Has consulted a number of oculists, and has\\ntried many kinds of glasses, without much relief. In fact, he\\nhad to give up his profession on account of his eyes, because,\\nafter reading for a short time, the pain in his eyes would\\nbecome unbearable.\\nHe has worn for the last two 5 ears 1.50 D. \u00e2\u0080\u00941.50 D.\\ncyl., 170\u00c2\u00b0 right, and -2 D. -ID. cyl., 180\u00c2\u00b0 left, combined with\\n5\u00c2\u00b0 prisms, bases in. These glasses gave him partial relief at\\nfirst, but for the last year he thinks the eyes have been made\\nworse. But as no other glasses of which he had many\\npairs, plus, minus, with prisms and without had given him\\nany relief, he held to these until forced to try something else.\\nI treated the eyelids for three months before testing for\\nglasses, as I wished to eliminate that factor of the trouble.\\nJanuary 3, 1899, I made the first test.\\nOphthalmomete7\\\\ Astigmatism with the rule, 2.50 D.,\\naxis 80\u00c2\u00b0 170\u00c2\u00b0 right eye with the rule, 2 D., axis 100\u00c2\u00b0\\nor 10\u00c2\u00b0 left eye.\\n-iwo T%~^ 1-25 D. 2 D. cyl., 170\u00c2\u00b0.\\nL. V. 2V0 ff W. 1.25 D. 2 D. cyl., 10\u00c2\u00b0.\\nReads Jaeger No. 1 from 7 to 24 inches. Ad. 11\u00c2\u00b0, ab. 13\u00c2\u00b0,\\nsur. R. 5\u00c2\u00b0, L. 4\u00c2\u00b0. Single binocular vision with effort.\\nOphthalmoscope.\u00e2\u0080\u0094 M. 3 D. at 75\u00c2\u00b0 and M. 1 D. at 165\u00c2\u00b0\\nright eye M. 3 D. at 105\u00c2\u00b0 and 1.50 D. at 15\u00c2\u00b0 left eye.\\nOrdered prism exercises.\\nJanuary 9. Ophthalmometer and ophthalmoscope gave the\\nsame readings as at the first test.\\nV. ^\u00c2\u00a50 ft- W. 1 D. 2.25 D. cyl., 170\u00c2\u00b0.\\nL. V. 2^0 ft W. 1.25 D. 1.50 D. cyl., 10\u00c2\u00b0.\\nAd. 17\u00c2\u00b0, ab. 10\u00c2\u00b0, sur. R. 4\u00c2\u00b0, and L 3\u00c2\u00b0.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0324.jp2"}, "325": {"fulltext": "ILLUSTRATIVE CASES 807\\nJanuary 18. A third test corresponded with the second.\\nSince this patient had had so many glasses, and all unsatis-\\nfactory, I put him under the influence of a mydriatic (scopola-\\nmine), and on January 27, tested him under it, as follows\\nOphthalmometer. Astigmatism with the rule, 2.50 D.,\\naxis 80\u00c2\u00b0 or 170\u00c2\u00b0 right 1.50 D., axis 100\u00c2\u00b0 or 10\u00c2\u00b0\\nleft eye.\\nTest cards and trial lenses.\\nR. V. 2Vo-MH- W-- .75 D. -2 D. cyl., 170\u00c2\u00b0.\\nL. V. -2V_ 1^ w. 1.25 D. 1.25 D. cyl., 10\u00c2\u00b0.\\nAd. 10\u00c2\u00b0, ab. 10\u00c2\u00b0, sur. R. 6\u00c2\u00b0, L. 4\u00c2\u00b0.\\nOphthalmoscope. \u00e2\u0080\u0094M. 3 D. at 75\u00c2\u00b0 and M. 1 D. at 165\u00c2\u00b0\\nright eye; M. 3 D. at 105\u00c2\u00b0 and M. 1.50 D. 15\u00c2\u00b0 left eye.\\nThe retinoscope confirmed the ophthalmoscopic and sub-\\njective tests. The angle alpha was 3\u00c2\u00b0 in each eye. Ordered\\nthe glasses that were accepted under the mydriatic.\\nFebruary 3. Patient reports entire relief from, all asthe-\\nnopic symptoms, is able to read for long hours without discom-\\nfort, and is altogether happy. There is none of the drawing\\nsensation in the eye as with the old glasses, and the weight of\\nthe glass itself is much less than the old heavy prismatic glasses.\\nThe old mistakes of over-correcting the spherical part of\\nthe error of refraction, and under-correcting the cylindrical\\npart, had been committed in this case, and besides these errors,\\nthe burdensome prisms of 5\u00c2\u00b0, bases in, were added to the\\nglasses. These prisms were gradually forcing the eye into a\\ndivergent squint. When I first saw the patient he had an\\nadduction of only 11\u00c2\u00b0 and an abduction of 13\u00c2\u00b0, and the patient\\n^as under a constant strain in order to have single binocular\\nvision.\\nAfter two weeks wearing of the glasses without prisms,\\nthe patient had ad. 18\u00c2\u00b0, ab. 9\u00c2\u00b0, sur. R. 1\u00c2\u00b0, L 3\u00c2\u00b0. He has been\\nunder observation for three months since the glasses were pre-", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0325.jp2"}, "326": {"fulltext": "308 THE REFRACTION OF THE EYE\\nscribed, expresses himself as being entirely comfortable, and\\nable to work with satisfaction for the first time in many years.\\nWhile on this question of prisms, I may say that within a\\nmonth I have removed a pair of prisms from a patient with\\na well-marked convergent strabismus, in which none of the\\nrefractive error had been corrected, the patient wearing a sim-\\nple prism 3\u00c2\u00b0, base out, in front of each eye. No binocular\\nsingle vision was present, and, of course, the prisms were\\nworse than useless. Except in cases of paralytic squint,\\nwhere they are to be recommended for temporary use until\\nthe patient has recovered under treatment, or by operation,\\nprisms should not be given in strabismus cases.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0326.jp2"}, "327": {"fulltext": "CHAPTER X\\nASTIGMATISM AFTER CATARACT EXTRACTION TORIC LENSES\\nPERISCOPIC LENSES DECENTERING OF LENSES ILLUS-\\nTRATIVE CASES\\nAs would be supposed, the aphakial or lensless eye, where\\nthe corneal astigmatism only has to be considered, is the ideal\\neye for the use of the ophthalmometer. Nevertheless, the nodal\\npoint is moved forward by the removal of the crystalline lens,\\nand hence the cylinder being combined, almost without excep-\\ntion, with a strong spherical glass, which must be worn one-\\nhalf inch in front of the eye, the strength of the glass necessary\\nfor the correction of the astigmatism is rarely ever as great as\\nthat indicated by the ophthalmometer, even though the astig-\\nmatism is against the rule. The same law for reduction in\\nstrength holds in regard to prescribing spherical glasses after\\ncataract extraction. For example, say the amount of hyper-\\nmetropia in an eye after cataract extraction is 11 D. Now,\\nsince there is no crystalline lens in such an eye, it Avould\\nnaturally seem that it would require a 4- 11 D. (3 J inch) lens\\nto correct this error, and, as a matter of fact, it would, could\\nthe glass be worn in contact with the cornea. But since the\\nordinary wearing distance of a glass from the eye is 12 to 14\\nmm., or about one-half inch, this moving forAvard of one-half\\ninch perceptibly increases the strength of strong convex glasses,\\nand, therefore, a reduction in strength must be made. In the\\npresent supposed example of 11 D. hypermetropia, instead of\\nthere being required a -t- 11 D. to correct it, a much weaker\\nglass, when placed at the usual one-half inch wearing distance\\nin front of the eye, will accomplish what is required. To be\\nexact, it would require a glass of only ojin. in. (^the Mn.\\n309", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0327.jp2"}, "328": {"fulltext": "310 THE REFRACTIOX OF THE EYE\\nbeing the distance in front of the eye that the glass is worn),\\nwhich equals a four-inch focus glass and a four-inch focus\\nglass equals 10 D. By which it is seen that one whole diopter\\nis- deducted from the glass.\\nThis increase of the power of convex glasses, on account of\\nthis one-half inch (projection from the cornea) in front of the\\neyes, obtains in all other eyes, as well as in aphakia, but the\\nglasses, as a rule, in other than aphakial eyes, are so weak that\\nthe slight displacement of one-half inch does not make a great\\ndifference in their strength. There are excejptional cases\\nwhere it does, but they are rare. In cataract cases, how-\\never, the glasses must be very strong, except when the eye\\nhas been strongly myopic before operation, and a slight change\\nin the position of the glass in front of the cornea makes a great\\ndifference in the power of the glass, as shown above. To give\\nanother example, say the patient was hypermetropic 5 D. before\\nthe operation, and after the operation that he has a hyper-\\nmetropia of 16 D. It is evident that if a plus glass of 16 D.\\n(2|- in. focus) could be worn in contact with the cornea it would\\ncorrect the 16 D. of hypermetropia but, as it must be worn\\none-half inch in front of the eye, it must be reduced in strength.\\nThat is, it would require a glass of 2^ -f- J S in. focus, which\\nequals only 13 D., a decrease in strength of three diopters.\\nThe discrepancy in the reading of the ophthalmometer\\nand the cylindrical glass accepted by the patient after cata-\\nract extraction is not because of an error in the reading of the\\ninstrument, but is to be ascribed chiefly to the great reduction in\\nstrength that has to be made in strong cylinders on account of\\nthe one-half inch distance at which they must be worn in front\\nof the eye, especiall} so when combined with strong spherical\\nglasses. For example, if we have an astigmatism of 3 D.\\nagainst the rule, 180\u00c2\u00b0 -h, and hypermetropia 10 D. the power\\nof the glass to correct in the vertical meridian would be 13 D.,\\nand the horizontal meridian 10 D., if they could be worn in con-", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0328.jp2"}, "329": {"fulltext": "ASTIGMATISM AFTER CATARACT EXTRACTION 311\\ntact with the eye. But they are one-half inch in front of the\\neye. 13 D. 3 in. focus, j in. (in front of the eye) 3J in.\\nfocus 11 D. for the vertical meridian. For the horizontal\\nmeridian, 10 D. 4 in., -f- in. 41 in. =9 0. The difference\\nbetween 11 D. and 9 D., the glasses which respectively it re-\\nquires to correct the vertical and horizontal meridians, on\\naccount of their position in front of the eye, is only 2D.; and,\\ntherefore, it would take but 2 D. cyl. to correct the 3 D. of\\ncorneal astigmatism. Again, take 6 D. of astigmatism, 180\u00c2\u00b0\\nwith 10 D. of H. The vertical meridian would require 16 D.\\n(21 in.) to correct it, if worn in contact with the eye-; 2^ in,\\nH- 1^ in. 3 in. 13 D., which glass it really takes. The\\nhorizontal meridian would take 10 D. (4 in.); 4 1 41 in.\\n9 D. Now, 13 D. 9 D. 4 D., the amount of cylinder,\\naxis 180\u00c2\u00b0, it takes to correct the 6 D. of corneal astigmatism.\\nCarl Weiland, in writing on the subject, has this to say\\nCases of aphakia are, therefore, the ideal field for kera-\\ntometry, but owing to the high spheres usually necessary, there\\nis a great difference between the correcting cylinder at 14 mm.\\nfrom the eye and that in contact with the cornea, which latter,\\nas we know, is given by Javal s instrument. The following\\ntable will show this at a glance, which is given for 10 D. for\\nfar, and 14 D. for reading.\\nTable\\nA\\nA\\nFull Cokrection\\nA\\nA\\nFull Corbection\\n1\\n10\\n10 .75 cyl.\\n1\\n14\\n14 .60 cyl.\\n1\\n10\\n10 .73 cyl.\\n1\\n14\\n14 .05 cyl.\\n-2\\n10\\n10 1.45 cyl.\\n2\\n14\\n14 1.25 cyl.\\n2\\n10\\n10 1.50 cyl.\\n2\\n14\\n14 1.3 cyl.\\n-3\\n10\\n10 2.1 cyl.\\n-3\\n14\\n14 1.8 cyl.\\n-4\\n10\\n10 2.8 cyl.\\n4\\n14\\n14 2.5 cyl.\\n-5\\n10\\n10 3.50 cyl.\\n-5\\n14\\n14 3. 18 cyl.\\n-6\\n10\\n10 4.1 cyl.\\n-0\\n14\\n14 3.06 cyl.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0329.jp2"}, "330": {"fulltext": "312 THE REFEACTIOX OF THE EYE\\nThis shows conchisively the necessity of correcting in\\naphakia the keratomically determined cylinder for its position\\nand for the coexisting axial condition, for even with a 1 D.\\nit amounts to .25 D. and more, while for an astigmatism of\\n6 D. against the rule, it amounts to almost 2.50 D. At the\\nsame time, we observe that in the same individual the cyl-\\ninder may have to be reduced perceptibly for reading. We\\nalso find that the numbers obtained by the keratometer are\\nalways too high, no matter whether the astigmatism is with or\\nagainst the rule.\\nTheoretically, Weiland s position is correct, but in prac-\\ntice, I have, more than once, seen the patient accept exactly\\nwhat the instrument indicated, and even more. As a general\\nthing, though, after cataract extraction, the patient will not\\naccept as much cylindrical correction as indicated by the\\ninstrument.\\nThere is another feature of error in the ophthalmometer\\nitself, in high degrees of astigmatism, 6 D. and over, spheri-\\ncal aberration.\\nThomas Reid, of Glasgow, in an article on the Scope and\\nLimits of Ophthalmometry, calls attention to this point. He\\nsays With Javal s instrument with an image of 3 mm., and\\nwith the portable ophthalmometer (Reid s) with an image of\\n2 mm., it is clear that from the spherical aberration the abso-\\nlute size of the radius cannot be determined without reduction,\\nas Leroy has done. Hence the necessity in these instruments\\nof being adjusted to a spherical surface of known curvature,\\nwhich at most expresses approximately the average curvature\\nof the cornea. The results obtained by these instruments\\nthus adjusted, although not theoretically perfect, will give\\nthe relative difference in degrees of corneal astigmatism\\n1 History and Principles of Keratometry, Knapp s Archives of Oj)hthal-\\nmology, January, 1893.\\n2 Annals of Ophthalmology, July, 1897, p. 456.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0330.jp2"}, "331": {"fulltext": "ASTIGMATISM AFTER CATARACT EXTRACTION 313\\nnot greater than 5 D. with sufficient accuracy for practical\\npurposes.\\nIn regard to the limit of the measuring power of the Javal-\\nSchiotz ophthalmometer, especially its capacity to determine\\nthe relative difference of the refractive power of the two\\nprincipal meridians, even in very high degrees of astigmatism,\\nI may say the same restriction does not hold in the Javal-\\nSchiotz instrument as in Reid s, and for the following reason\\nIn both instruments the size of the image remains constant\\n(3 mm. in Javal s, and 2 mm. in Reid s), but the size of the\\nobject varies.\\nIn Reid s instrument,^ the object measured is an iris dia-\\nphragm, which can be made to vary in size. Now, in this\\ninstrument, if we take the extremes of the index, 12 mm.\\nand 16 mm., we find the corresponding diopters are 38.9 D.\\nand 51.84 D. The difference between these two amounts,\\n51.84 38.9 12.94, or about 13 D., the amount of the astig-\\nmatism (with the prism giving an image of 2 mm.) the instru-\\nment is capable of measuring.\\nIn Javal s instrument, the object is the distance between\\nthe inner edges of the mires. When both of these mires\\nmove at once, as in the instrument with the double movable\\nmires, the size of the object can be made to change from\\n10 cm. (100 mm.) to 40 cm. (400 mm.), the corresponding\\ndiopters to these numbers equal 20 D. and 80 D., respectively\\nand the difference between 80 D. and 20 D. equals 60 D., the\\namount of astigmatism the instrument is capable of measur-\\ning. Of course it could show such a great difference in only\\na relative way, because the spherical aberration would be so\\ngreat in such a case that the measurement would not be\\naccurate, but only approximate.\\nBut it is the difference in the limit of the measuring power\\nof the two instruments I wish to show. One has the capacity\\n1 See description of Reid s Ophthalmometer in Appendix.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0331.jp2"}, "332": {"fulltext": "314 THE REFRACTION OF THE EYE\\nto measure 13 D. of astigmatism, while the other has the\\ncapacity to measure 60 D. While no such amount as 60 D.\\nof astigmatism has ever been met with in practice, yet so\\nlarge amount as 28 D. of astigmatism (and not after cataract\\nextraction) has been seen and measured with the Javal oph-\\nthalmometer, the patient accepting exactly the cylindrical\\nglass indicated by the instrument.\\nBoth the Javal and the Reid instruments may have the\\nlimit of their measuring power increased by taking out the\\nusual birefractive prisms that come with them, and substituting\\nprisms that give an image of only 1 to 1^ mm. in diameter.\\nBut ordinarily this is not required, and, moreover, it is not\\nconvenient. Except for scientific investigations, these extra\\nprisms are not necessary, because both instruments are capable\\nof measuring any case of astigmatism ordinarily met with\\nfor, except in cases of conical cornea and cases after cataract\\nextraction, we rarely encounter an astigmatism of more than\\n5 or 6 D. As far as the cases of conical cornea are concerned,\\nfortunately they are rare, even they can be measured fairly\\naccurately with the ophthalmometer.\\nAs for the astigmatism we meet with after cataract extrac-\\ntion, while it is very great in some cases shortly after the ex-\\ntraction (two to three weeks), amounting in rare instances to\\nas much as 22 D., this, as a rule, rapidly diminishes, till within\\nsix weeks to two months it rarely amounts to more than 5 or\\n6 D., although in one case I have seen 12 D. of astigmatism\\nremain permanently after extraction. So here again the oph-\\nthalmometer is within its range of practical and accurate work.\\nThe latest investigations as to the amount of the astigma-\\ntism after cataract extraction, both immediately (two weeks)\\nafter and several months later, are those of E. O. Pfingst, of\\nLouisville, in Knapp s Archives of Ophthalmology. In a series\\n1 Dodd s case, cited in full farther on in this chapter.\\n2 Bd. Vol. XXV, 1896, pp. 333-340.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0332.jp2"}, "333": {"fulltext": "ASTIGMATISM AFTER CATARACT EXTRACTION 315\\nof .fifty cases, lie found that the astigmatism, two weeks after\\noperation, ranged from 1.75 D. with the rule to 22 D. against\\nthe rule that this rapidly diminished in amount for the next\\ntwo to four weeks, then gradually diminished in amount for\\nsix months, after which, in the few cases which he had the\\nopportunity of examining, he found no further change in the\\nastigmatism.\\nMy own experience is similar to that of Pfingst and others\\nwho have made investigations in this class of cases. In pri-\\nvate practice, and especially at the Manhattan Eye and Ear\\nHospital, where I was Interne for two years, I have made\\nmany observations with the ophthalmometer after cataract\\nextractions. In some cases I have made the examination as\\nearly as the tenth day after the extraction. The first examina-\\ntion usually showed a considerable amount of astigmatism\\nagainst the rule (4 to 8 D.), while one showed as much as\\n22 D. In a few cases, the astigmatism was with the rule, and\\namounted to as much as 4.50 D. in one case.\\nIn all of the cases that I have observed, the astigmatism\\nhas rapidly diminished in amount, till in no case, with two\\nexceptions, six months after operation, did it amount to as\\nmuch as 8 D., even where the astigmatism had been as much\\nas 22 D. the first two weeks after operation. Eurthermore,\\nin some cases of astigmatism against the rule of as much\\nas 4 D. to 6 D. in amount, it vanished entirely; and, in some\\ncases, an astigmatism of as much as 2 D. to 4 D. ao-ainst\\nthe rule changed to astigmatism with the rule. One case\\nof 4.50 D. astigmatism with the rule diminished gradually\\nto nothing, then an astigmatism of 1.50 D. against the rule\\ndeveloped.\\nComplicated cases of cataract extraction are the ones that\\ngive rise to the largest amounts of astigmatism, incarceration\\nof the iris in the whole length of the wound exerting the q-reat-\\nest influence on the shape of the cornea, perhaps. Pringst s", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0333.jp2"}, "334": {"fulltext": "316 THE REFRACTION OF THE EYE\\ncase of 22 D. had this complication. The case of 22 D.\\nobserved by me occurred in a woman whom I operated on\\nat the hospital, who fell over backward from a stool at\\nthe end of the first week after the operation, and pulled\\nopen the wound. This wound, in healing the second time,\\nwas grooved, and caused the very large amount of astigma-\\ntism described.\\nIn his series of fifty cases, Pfingst stated that no case\\naccepted more than 6 D. cylinder, although one case had as\\nmuch as 22 D. astigmatism shortly after the operation. In\\nthe case of 22 D. of astigmatism against the rule observed by\\nme, the patient would not accejDt more than 8 D. cylinder at\\nthe first test, and, afterward, when the astigmatism had been\\nreduced to 5 D., the patient accepted 4 D. cylinder, in con-\\njunction with the sphere for distance, and 3.50 D. cylinder\\nwith the sphere for reading.\\nI have, however, seen one case where the patient accepted\\n16 D. cylinder twenty-seven days after the operation. It was\\na case where incarceration of the iris in the whole length of\\nthe wound had taken place and still another case, in which\\n11.50 D. cylinder, combined with a 4 D. sphere, was accepted\\nfor constant wear and with comfort. In the latter case, the\\nwound pulled open twice during the healing process, and left\\na deep groove. Both of these cases are reported in full far-\\nther on in this chapter.\\nOne feature, of which Pfingst did not speak in his article,\\nwas the change in the axis of the astigmatism. I have found\\nit to vary from five to thirty degrees in the first six weeks.\\nThis is to be accounted for by the healing process in the\\nwound, the contraction of the scar, and, perhaps, to some\\nextent, from the pressure of the lids during the healing. The\\naxis of the astigmatism finally settled down to a definite place,\\njust as the amount of the astigmatism did, after about six\\nweeks time.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0334.jp2"}, "335": {"fulltext": "DECENTERING LENSES 317\\nOwing to the change, both in the amount and the axis of\\nthe astigmatism, after cataract extraction, only temporary\\nglasses should be given till the end of the second month after\\nthe operation, and it is safer to wait for five or six months\\nbefore giving permanent glasses.\\nThe correct adjustment of glasses after cataract extraction,\\nespecially where both eyes have been operated upon, is an\\nimportant matter. The adjustment for the distance or street\\nglasses is quite different from that for the near or reading\\nglasses. While the distance glasses should rest almost in the\\nvertical plane, being very slightly tilted forward at the top to\\novercome spherical aberration, or a small amount of astigma-\\ntism, if present, and should be centered with the pupils, the\\nglasses for the reading distance are to be decentered toward\\nthe nose, and should be worn at a lower plane or level than the\\ndistance glasses, in order to allow the patient to look through\\nthe center of them. If this adjustment is not given to the\\nnear glasses, they act as prisms, bases out, and cause diplopia\\nfor the near point in the horizontal plane and, if not worn at\\na lower level than the distance glasses, they act as prisms,\\nbases up, causing diplopia in the vertical plane the combined\\naction giving a crossed vertical diplopia.\\nHolden has given a working formula for the decentering of\\nlenses, as follows\\nPx9\\nM=\\nD\\nin which M is the number of millimeters of decentering that\\nis required to give a lens, i of a certain power, to get the\\neffect of a prism, P, of a certain number of degrees. As he\\nsays For the effect of any prism, multiply 8.7 mm. [practi-\\ncally 9] by the number of that prism, and for any lens divide\\nthis product by the number of diopters of the lens.*\\n1 Knapp s Archives of Ophthalmology, January, 1891, Vol. XX, pp. 1-25.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0335.jp2"}, "336": {"fulltext": "318 THE REFRACTION OF THE EYE\\nFor example, say we have a lens of 6 D. in each eye, which\\nwe wish to decenter inwards, so as to act as prisms of 2\u00c2\u00b0,\\nbases in,\\n6\\nthe number of millimeters of decentering required to give such\\na lens (6 D.) so as to act as a 2\u00c2\u00b0 prism.\\nNo displacement should be more than 7 mm. in each eye.\\nThe practice that is, I regret to say, sometimes followed, of\\nputting a distance glass in one side of a reversible spectacle\\nframe, and the reading glass in the other side, where but one\\neye has been operated upon, and causing the patient to reverse\\nthe frames when he wishes to change from distant to near\\nvision, is an exceedingly bad one with such frames, it is\\nimpossible to give the correct adjustment, even with those that\\nare reversed by turning on a vertical axis. I make it a rule,\\ntherefore, to give my cataract patients two pairs of glasses, one\\nfor the distance and one for the near point.\\nSpherical and chromatic aberration are other troublesome fea-\\ntures, that are coincidental to the strong glasses necessary\\nafter cataract extraction, and must not be lost sight of. I\\nwish to speak especially of spherical or monochromatic aberra-\\ntion, as it is sometimes called.\\nWilliam Harkness has shown that with a pupil four mm.\\nin diameter the normal cornea produces monochromatic aberra-\\ntion to the extent of 3^3 (1.2 D.); and as there is no confusion\\nof images in the normal eye, it seems probable tliat the crystal-\\nline lens exerts some compensating action. This suspicion is\\nstrengthened by the well-known fact that in aphakia the acute-\\nness of vision is nearly always improved by giving a certain\\ninclination to the powerful convex glasses which are necessary.\\nBut the tilting of the strong convex glasses, necessary in\\ncataract cases, serves not only to overcome this spherical\\n1 Knapp s Archives of Ophthalmology, Bd. Vol. XII, p. 18.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0336.jp2"}, "337": {"fulltext": "TILTING OF LENSES 319\\naberration spoken of by Harkness, but also for correcting in\\npart or whole the astigmatism usually present after cataract\\nextraction. Since this astigmatism is generally against the\\nrule, that is, the vertical meridian, or one near it, is made\\nflatter by the contraction of the scar, it can be easily corrected\\nby rotating the strong spherical glass on the horizontal axis, or\\none near to it, the rotation being greater or less according to\\nthe astigmatism to be corrected.\\nDr. Green, of St. Louis, in a valuable and instructive paper,\\nAn Elementary Discussion of some Cases of Centrical Refrac-\\ntion through Tipped Spectacle Lenses, Transactions American\\nOphthalmological Society, Bd. Vol. V., 1888-90, pp. 690-717,\\ndiscusses the subject of tilting of lenses, both spherical and\\ncylindrical, at length, and at the close of the paper gives a\\ntable showing the effect of tilting lenses a certain number\\nof degrees. I give his conclusions and the table.\\nHe says The change effected in the power of any lens by\\ntipping may be summed up as follows\\nEvery spherical lens is increased in power in all its merid-\\nians; the rate of increase and the actual increase being greatest\\nin the vertical and the least in the horizontal meridian. A\\nspherical lens is, therefore, also rendered astigmatic, and the\\nexcess of increase in power in the vertical meridian over that\\nin the horizontal, for any given inclination, is the measure of\\nthe astigmatism.\\nEvery convex or concave toric or sphero-cjdindrical lens is\\nincreased in power in all its meridians. When the two princi-\\npal meridians of the lens lie in the vertical and in the hori-\\nzontal plane, respectively, the rate of increase in power is\\ngreatest in the vertical and least in the horizontal meridian\\nand when the power of the untipped lens is greatest in the\\nvertical meridian the actual increase is also greatest in the\\nvertical meridian, and the astigmatism of the lens is increased.\\nWhen, on the other hand, the power of the untipped lens is", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0337.jp2"}, "338": {"fulltext": "320\\nTHE REFRACTIO:Nr OF THE EYE\\ngreatest in the horizontal meridian, the astigmatism of the\\nlens is at first diminished, and since the possible increase in\\npower in the horizontal meridian is limited, there is always\\nsome value of cj) (the angle of tipping or inclination) at which\\nthe astigmatism of the lens is reduced to zero, and beyond\\nwhich the direction of the meridians of greatest and least\\nrefraction is reversed.\\nIn the case of a tipped piano-cylindrical (or other equiv-\\nalent) lens, the greatest increase in power is in the meridian at\\nright angles to the axis of the lens, the power of the lens in the\\nmeridian of the axis remaining at zero, the rate of increase, and\\nalso the actual increase in power is greatest when the axis of\\nthe untipped lens is horizontal, and is least when the axis of\\nthe untipped lens is vertical.\\nThe table that he gives shows the relative increase in\\npower of a lens of given strength when tipped a certain num-\\nber of degrees, beginning at the vertical where it is tipped no\\nor zero degrees, and gradually increased to 90\u00c2\u00b0. However,\\nI may say, that it is not practicable to tip any lens more\\nthan 20\u00c2\u00b0.\\nTable\\nAngle of\\nTipping\\nSphere\\nCylinder or Equiv-\\nalent, Axis 180\u00c2\u00b0\\nCylinder or Equiv-\\nalent, Axis 90\u00c2\u00b0\\nzero\\n1.\\n1.\\n0.\\n5\u00c2\u00b0\\n1.010\\n1.002\\n0.008\\n10\u00c2\u00b0\\n1.012\\n1.010\\n0.032\\n15^\\n1.097\\n1.023\\n0.074\\n20\u00c2\u00b0\\n1.179\\n1.041\\n0.138\\n25\u00c2\u00b0\\n1.297\\n1.066\\n0.231\\n30\u00c2\u00b0\\n1.462\\n1.096\\n0.366\\n35\u00c2\u00b0\\n1.689\\n1.134\\n0.555\\n40\u00c2\u00b0\\n2.008\\n1.178\\n0.830\\n45\u00c2\u00b0\\n2.464\\n1.232\\n1.232\\n90\u00c2\u00b0\\ninfinity\\n2.236\\ninfinity", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0338.jp2"}, "339": {"fulltext": "TILTING OF LENSES\\n321\\nWard A. Holden, in a most excellent and practical article\\non this subject,^ gives a working table for the tilting of lenses,\\nwherein he not only shows the relative increase in power of\\na spherical lens by being tilted a certain number of degrees,\\nbut the actual increase in power of the lenses most commonly\\nused after cataract extraction. I append the table, as it is\\nof practical value.\\nTable\\nSpherical, Focus\\nIN Inches\\nTilting 10\u00c2\u00b0\\nTilting 15\u00c2\u00b0\\nTilting 20\u00c2\u00b0\\n4i\\n\u00e2\u0096\u00a0Tio\\n\u00e2\u0096\u00a05\\\\-\\n4\\nTio\\n^V\\n^v-\\nH\\nio\\nz\\\\\\n2V\\nH\\n\u00e2\u0096\u00a0h\\nio-\\n^v-\\n3\\nio\\n^v\\n2|\\ni^\\ni-.-\\ntV\\nn\\ni,\\n\u00e2\u0096\u00a0h\\nTo give an example, say a spherical glass of 21 inch focus\\n(16 D.), often given as a reading glass after cataract extrac-\\ntion, is tipped forward 10\u00c2\u00b0, it would increase its strength in\\nthe vertical meridian .50 D. if tipped 15\u00c2\u00b0, it would increase\\nits power in the vertical meridiaji 1.25 D. and, if tipped 20\u00c2\u00b0,\\nit would increase its power in the vertical meridian 2.25 D.\\nIn each instance, however, it would also slightly increase the\\nstrength of the glass in the horizontal meridian. Now, if there\\nwas only a small amount of astigmatism against the rule, axis\\n180\u00c2\u00b0, this could be easily corrected by tilting the strong plus\\nspherical glass.\\nThere is one disadvantage, incidental to the tipping of\\n1 On the Cylindrical Equivalent of Tilted Lenses, the Prismatic Equivalent\\nof Decentered Lenses, and the Employment of such Lenses in Practice.\\nKnapp s Archives of Ophthalmology Vol. XX, pp. 1-25.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0339.jp2"}, "340": {"fulltext": "322 THE REFRACTION OF THE EYE\\nstrong spherical glasses, which Holden points out. He says\\nThe spherical lens tilted on a horizontal axis has the disad-\\nvantage that the refractive error is corrected only while the\\neye remains in a given horizontal plane. Suppose the upper\\nedge of the glass tilted from the patient. Then, if he look\\nthrough the lower part of the glass, the visual axis of the eye\\ncomes to form a smaller angle with the axis of the lens, and\\nthe effect of the tilting is correspondingly lost. If he look\\nthrough the upper part of the glass, the visual axis is at a\\ngreater angle with the axis of the lens, and the refractive\\npower is increased. For this reason, tilted spherical lenses are\\nless adapted for distance than for reading.\\nIncidentally, it may be referred to again that myopic astig-\\nmatism with the rule^ when associated with myopia of high\\ndegree, can be corrected by tilting the strong spherical glass\\non its horizontal axis. This follows from the fact that in com-\\npound myopic astigmatism with the rule, just as hypermetropic\\nastigmatism against the rule, the meridian of greatest error\\nlies in the vertical plane, or one near it and, by tilting the\\nstrong sphere on its horizontal axis, it acts more strongly in\\nthe vertical plane than in the horizontal and, in this way,\\nsmall amounts of astigmatism can be corrected when associated\\nwith high degrees of spherical error. Except in very high\\ndegrees of myopia, 10 to 18 D., with astigmatism of small\\namount, 1 to 3 D., with the rule, this method should not be\\nadopted for, as pointed out by Donders This means of\\ncorrecting astigmatism is, however, capable of application only\\nwhen relatively strong spherical glasses are required to neu-\\ntralize the ametropia and then, too, a more perfect correction\\nwill be attainable by cylindrical curvature of one of the sur-\\nfaces. Only in aphakia can we advantageously, in my opinion,\\nin order to correct a certain degree of astigmatism, make use\\nof an oblique position of the glasses. Almost always it\\n1 Loc. cit. 2 Accommodation and Befraction of the Eye^ p. 511.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0340.jp2"}, "341": {"fulltext": "TORIC AND PERISCOPIC LENSES 323\\nappears that when we give a certain inclination to the strongly\\n\u00e2\u0080\u00a2convex glass the acuteness of vision is improved, and the neces-\\nsity of attending strictly to this in every case of aphakia is\\ngenerally recognized.\\nBefore proceeding to give illustrative cases, I wish to speak\\nvery briefly of toric and periscopic lenses.\\nToric Lenses. Dr. John Green gives the following defini-\\ntion of a toric lens When a circle is revolved about a line\\nin its own plane as an axis, a toric surface is generated. When\\nthe axis of revolution is a chord, other than a diameter of\\nthe generating circle, two toric surfaces are generated, by the\\ngreater and lesser arcs, respectively (Fig. 103, A). When the\\nA B\\nFig. 103 (after John Green)\\naxis is taken outside the generating circle, the toric surface\\nhas the form of a ring (Fig. 103, B^. The plane of the cir-\\ncumference described by the center of the generating circle\\ncuts the toric surface equatorially. When the axis of revolu-\\ntion is taken outside the generating circle, this plane cuts the\\ntoric surface in two equatorial circles, a lesser and a greater,\\nwhich have a common center at the point in which the equa-\\ntorial plane cuts the axis of revolution, which point is the\\ncenter of the torus. Every plane passing through the axis of\\nrevolution cuts the toric surface meridionally.\\nA toric lens, then, is one whose two cylindrical surfaces,\\nwith different length radii, are ground on one side of a lens\\nwith their axes at rigrJit anoies to each other. The other side\\noi the lens may be plane, or have a plus or minus sphere\\n1 Transactions American Oph. Soc, Bd. Vol. V, 1888-90. pp. ()90-T17.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0341.jp2"}, "342": {"fulltext": "324 THE REFRACTION OF THE EYE\\nground on it. Such glasses are especially applicable after\\ncataract extraction, or in other cases when strong spheres\\nhave to be combined with cylinders. To give an example,\\nsay after cataract extraction a patient accepts 10 D. -f 4\\nD. cyl., 180\u00c2\u00b0. Instead of giving this glass in the ordinary\\nform, 10 D. spherical ground on one side and 4 D. cyl.,\\n180\u00c2\u00b0, on the other, it can be ground in the toric form, as fol-\\nlows Grind 5 D. sphere on one side, instead of the +10 D.,\\nand on the other side 9 D. cyl., 180\u00c2\u00b0, 5 D. cyl., 90\u00c2\u00b0. To\\ngive another example, say a patient accepts 14 D. 5 D.\\ncyl., 180\u00c2\u00b0. It may be written in a toric lens thus 8 D.\\n11 D. cyl., 180\u00c2\u00b0, 6 D. cyl., 90\u00c2\u00b0. Such a combination\\nmakes a thinner glass, gives a wider field, causes less spherical\\naberration, and secures better vision, than the ordinary sphero-\\ncylindrical glass. They are considerably more expensive than\\nthe ordinary glasses, but are much more preferable, and when\\nthe patient is able to pay for them should be prescribed. As a\\nmatter of fact, the profession has been tardy in recognizing\\nthe value of these glasses, for they are of signal advantage in\\nmany cases of refraction, even where no extraction has been\\nperformed, especially where the glasses are of a moderate or\\nhigh power. Some examples will serve to illustrate their\\nadvantage.\\n(1) Compound hypermetropic astigmatism, where the\\npatient accepts 2 D. 2 D. cyl., 90\u00c2\u00b0. A favorable toric form\\ninto which it can be transposed is, 2 D. 4 D. cyl., 180\u00c2\u00b0 -f-\\n6 D. cyl., 90\u00c2\u00b0 in which case the \u00e2\u0080\u00942D. spherical glass is\\nground on one side and the plus cylinders at right angles on\\nthe other. Or, secondly, one side of the glass could be left\\nplane and plus cylinders ground at right angles on the other,\\nthus 2 D. cyl., 180\u00c2\u00b0 4 D. cyl., 90\u00c2\u00b0. Thirdly, part of the\\nsphere only could be ground on one side and cross cylinders\\non the other, thus 1 D. 1 D. cyl., 180\u00c2\u00b0 3 D. cyl., 90\u00c2\u00b0.\\nThe first of the three toric forms into which the ordinary glass", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0342.jp2"}, "343": {"fulltext": "TORIC AND PERISCOPIC LENSES 325\\nis converted is the best, as it gives a periscopic effect, of which\\nwe will speak presently under periscopic lenses.\\n(2) Simple hypermetropia astigmatism patient accepts\\n4 D. cyl., 90\u00c2\u00b0. A good toric form of this is 2 D. 2 D.\\ncyl., 180\u00c2\u00b0 6 D. cyl., 90\u00c2\u00b0.\\n(3) Compound myopic astigmatism patient accepts 2D.\\n-2D. cyl., 180\u00c2\u00b0. A good toric form is 5 D. 1 D. cyl.,\\n180\u00c2\u00b0 3 D. cyl., 90\u00c2\u00b0. Again, take a higher myopia; say the\\npatient accepts 8 D. 2 D. cyl., 180\u00c2\u00b0. Part of the minus\\nsphere can be ground on one side, and part on the other side in\\nconjunction with the minus cylinder as a torus thus 5 D.\\n5 D. cyl., 180\u00c2\u00b0 -3D. cyl., 90\u00c2\u00b0.\\n(4) Simple myopic astigmatism; patient accepts 4 D. cyl.,\\n180\u00c2\u00b0. Toric as follows -5 D. +5 D. cyl., 90\u00c2\u00b0 l D. cyl., 180\u00c2\u00b0.\\n(5) Mixed astigmatism patient accepts 2D. cyl., 180\u00c2\u00b0\\n2 D. cyl., 90\u00c2\u00b0. Toric as follows 4 D. 6 D. cyl.,\\n90\u00c2\u00b0 2D. cyl., 180\u00c2\u00b0.\\nWhere the glasses are not too strong, in transposing them\\ninto the toric form, we usually make them periscopic in shape\\nalso that is, we grind them in the form of a meniscus (see\\nperiscopic lenses immediately following). In this way the\\nadvantages of both forms (toric and periscopic) are gained.\\nAfter cataract extraction and where astigmatism is present,\\nthe glasses are very heavy here part of the plus sphere must\\nbe ground on one side, while the remainder of the sphere,\\ntogether with the cylinder, may be ground on the other side\\nin the form of a torus.\\nDr. John Green, of St. Louis, and Dr. George C. Harlan,\\nof Philadelphia, introduced toric lenses to the notice of the\\nAmerican profession, and made known by their writings the\\nadvantages of such lenses over ordinary lenses. However,\\ntoric lenses have not met with the favor they so mucli deserve.\\n1 Green, Transactions American Oph. Soc, Bd, Vol. Y., p. 709. Ilarlau,\\nLog. cit., 1885, 1889.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0343.jp2"}, "344": {"fulltext": "326 THE REFRACTION OF THE EYE\\nDr. George J. Bull,i of Paris, gives a full account of toric\\nlenses in a late publication of his, and I refer my readers ta\\nthe writings of Harlan, Green, and Bull for a full exposition of\\nthe subject.\\nPeriscopic Lenses. The term periscojnc comes from two\\nGreek words, Tre/^t, around, about, and aKoirelv, to see that\\nis, they are ground in such shape that the patient can see a\\nwell through the margin of the glass as through the center.\\nThe form of such glasses, therefore, is that of a meniscus that\\nis, concave on one side and convex on the other. If the con-\\ncave side is more curved than the convex, it acts as a negative\\nglass and if the convex side is more curved than the concave,\\nit acts as a convex glass.\\nSuch glasses are not suitable after cataract extraction, or in\\nhigh-power glasses of any kind, on account of their weight\\nbut weak and moderately strong glasses should always be\\nground in this form (meniscus) in preference to the ordinary\\nform. In private practice I usually order this form of glass.\\nThe following are a few examples by way of illustration\\n(1) Compound hypermetropic astigmatism patient accepts\\n-f 2 D. -h 2 D. cyl., 90\u00c2\u00b0. Periscopic form 4 D. -1- 6 D.\\n2 D. cyl., 90\u00c2\u00b0.\\n(2) Simple hypermetropic astigmatism patient accepts\\n-F 4 D. cyl., 90\u00c2\u00b0. Periscopic form 4 D. 4 D. -f- 4 D.\\ncyL, 90\u00c2\u00b0.\\n(3) Compound myopic astigmatism patient accepts 2 D.\\n-2D. cyl., 180\u00c2\u00b0. Periscopic form -5 D. 1 D. 2 D.\\ncyl., 90\u00c2\u00b0.\\n(4) Simple myopic astigmatism patient accepts 4 D.\\ncyl., 180\u00c2\u00b0. Periscopic form 5 D. 1 D. 4 D. cyl., 90\u00c2\u00b0.\\n(5) Mixed astigmatism; patient accepts 2D. cyl., 180\u00c2\u00b0\\n-h 2 D. cyl., 90\u00c2\u00b0. Periscopic form 4 D. 2 D. 4 D..\\ncyl., 90\u00c2\u00b0.\\n1 Bull, Lunettes et Pince-Nez, Paris, G. Masson.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0344.jp2"}, "345": {"fulltext": "ILLUSTRATIVE CASES 327\\nt\\nEven simple spherical glasses can be groiand in the peri-\\nBoopic or meniscus form. For example, 2 D. Periscopic\\nform 2 D. 4 D. Again, take a minus spherical glass,\\n-2D. Periscopic form 4 D. 2 D.\\nIllustrative Cases\\nIn giving the following illustrative cases of astigmatism\\nafter cataract extraction, I have selected them from my private\\nand hospital practice. I have also selected cases from the\\nclinics of Professors Koosa, Webster, Emerson, Pomeroy, and\\nLewis, at the Manhattan Eye and Ear Hospital, who kindly\\nallowed me to make use of any cases that I wished to. I may\\nsay here that these cases came under my personal observation\\nwhile I was Interne at the Hospital.\\nIn selecting illustrative cases, I have had two points in\\nview first, to show typical forms of astigmatism after cataract\\nextraction and, second, atypical and exceptional cases. In\\nall of these cases, the ophthalmometer proved of the greatest\\npossible value in recording the changes in the form of the\\ncornea.\\nCase CXIX. Astigmatism against the rule^ 3.50 D., axis^\\n180\u00c2\u00b0, two weeks after operation; 1.50 i axis 180\u00c2\u00b0, six weeks\\nafter extraction; Patient accepts 10 i .75 I), cyl.^ 180\u00c2\u00b0,.\\nand gets vision^ six weeks after operation. October 6, 1890;\\nSarah S., aged sixt3^-one years, in good health, had a simple\\nextraction of cataract from the left eye by Dr. Webster.\\nSmooth operation, the eye did well, and the patient was dis-\\ncharged after three weeks stay in the hospital.\\nOphthalmometer. Two weeks after operation, astigmatism\\nagainst the rule, 3.50 D., axis 180\u00c2\u00b0; three weeks, 3 D., 180\u00c2\u00b0\\nsix weeks, 1.50 D., 180\u00c2\u00b0.\\nTest cards and trial le7ises. Two weeks,\\nL. V. |-J W. 8 D. 4- 2.75 D. cyl., 180\u00c2\u00b0.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0345.jp2"}, "346": {"fulltext": "328 THE REFRACTIOX OF THE EYE\\nThe ophthalmoscope and oblique illumination showed a\\nlight membrane in the pupil. This was needled. Four weeks\\nlater, and six weeks after the extraction, the ophthalmometer\\nshowed but 1.50 D. of astigmatism against the rule, axis 180\u00c2\u00b0.\\nPatient accepted 10 D. .75 D. cyl., 180\u00c2\u00b0, and got V. ff\\nRead Jaeger No. 1 at 12 inches with 13 D. .75 D. cjd.,\\n180\u00c2\u00b0. Both the distance and reading glasses were ordered.\\nIn testing for cataract glasses, part or the whole of the\\nspherical error should be corrected before attempting to cor-\\nrect the astigmatism, especially if the astigmatism be of small\\nor only moderate degree. This conforms to the exception\\ngiven in the first part of this book in fitting cases of astig-\\nmatism associated with high degrees of hypermetropia and\\nmyopia, except in cases where there has been a large amount\\nof myopia before the operation. After cataract extraction the\\neye is rendered excessively hypermetropic, and, as a conse-\\nquence, part of this spherical error has to be corrected before\\nthe effect of the cylindrical correction is appreciated.\\nFor reasons already given in the first part of the chapter,\\nthe patient will not usually accept as strong cylindrical glasses\\nas indicated by the ophthalmometer, even though the astigma-\\ntism be against the rule. The amount of the astigmatism\\nafter cataract extraction is not of as great importance as the\\naxis for, as we can have no spasm of accommodation to deal\\nwith, by simply increasing the strength of the spherical glasses,\\nwe soon arrive at the glasses that give the best vision, pro-\\nAdded we have the correct axis at which to place the cylindrical\\nglass. At least, this has been my experience. I have found\\nthe ophthalmometric the very best method of all the objective\\nones for keeping the record of the changes in the curvature of\\nthe cornea after cataract extraction.\\nCase CXX. Astigmatism of large amount^ 8.50 Z)., against\\nthe rule, axis 15\u00c2\u00b0, ttvo weeks after operation; 7 i axis 180\u00c2\u00b0,\\nseven iveeks after operation; V. ivith 10 D. 5 i cyl.,", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0346.jp2"}, "347": {"fulltext": "ILLUSTRATIVE CASES 329\\n180\u00c2\u00b0, seven weeks after the operation. April 28, 1891, Israel K.,\\naged forty-five years, in good health, had a simple extraction\\nof cataract from the left eye by Dr. Roosa. The operation\\nwas without complication, the patient did well, and was dis-\\ncharged from the hospital at end of two weeks.\\nOphthalmoyneter. Two weeks after operation, astigmatism\\nagainst the rule, 8.50 D., axis 15\u00c2\u00b0 seven weeks, 7 D., axis\\n180\u00c2\u00b0.\\nTest cards and trial lenses. Two weeks,\\nL- V. W. 10 D. 6 D. cyl., 15\u00c2\u00b0.\\nThe ophthalmoscope and oblique illumination showed a\\nlight membrane in the pupil.\\nSeven weeks after the operation, the patient accepted\\n10 D. 5 D. cyl., 180\u00c2\u00b0, and got f^ V. and read Jaeger No.\\n2 at 10 inches with 4 D. sphere added. Both the distance\\nand reading glasses were ordered. The astigmatism in this case\\ndid not decrease as much as is usual after extraction, being-\\nreduced at the end of seven and one-half weeks only 1.50 D.,\\nthat is, from 8.50 D. to 7 D. At the same time the axis\\nchanged from 15\u00c2\u00b0 to 180\u00c2\u00b0, or the distance of 15\u00c2\u00b0.\\nCase CXXI. Astigmatism of large amount, 6 i)., against\\nthe rule^ two iveeks after operation; Reduced to 1.50 D., two\\nmonths after operation Patient at that time accepted all of the\\nastigmatism indicated hy the ophthalmometer and got vision.\\nNovember 4, 1896, Mrs. S. J. C, aged fifty-five years, in good\\nhealth, had a simple extraction of cataract from the left\\neye by me at her home. The operation was Avithout com-\\nplication, and the patient was discharged on the sixteenth day.\\nOphthalmometer. Sixteenth day, astigmatism against the\\nrule, 6 D., axis 150\u00c2\u00b0 one month, 4 D., axis 150\u00c2\u00b0 two and\\none-half months, 1.50 D., axis 15\u00c2\u00b0.\\nTest cards and trial lenses. Sixteenth day,\\nL. V. |-J W. 10 D. -f- 4 D. cyl., 150^", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0347.jp2"}, "348": {"fulltext": "330 THE REFRACTION OF THE EYE\\nOphthalmoscope and oblique illumination show a clear\\npupil.\\nTwo and one-half months after the operation, the ophthal-\\nmometer showed astigmatism of only 1.50 D., which the\\npatient accepted in full.\\nL. V. ffW. -f-13D. 1.50D. cyl., 150\u00c2\u00b0.\\nReads Jaeger No. 1 at 12 inches with 17 D. 1 D. cyl.,\\n150\u00c2\u00b0. Both the distance- and reading glasses were ordered,\\nwhich she has worn with comfort ever since, two and one-half\\nyears, and maintains the same good vision.\\nIt will be noticed in this case that the cylinder had to be\\nreduced in strength in the reading glass. The reason for this\\nhas already been discussed in this chapter.\\nCase CXXII. Astigmatism with the rule^ 1.50 i)., twelve\\ndays after operatio7i; Astigmatism did not change in amount or\\naxis Patient accepted the full amount of astigmatism indicated\\nhy the instrument^ and obtained |-g V, when combined with the\\nproper spherical glass. October 22, 1890, Julia A. W., aged\\nsixty-five years, in fairly good health, had a simple extraction\\nof cataract from the left eye by Dr. Pomeroy. The operation\\nwas without complication, and the patient was discharged on\\nthe twelfth day.\\nOphthalmometer. Twelve days, astigmatism with the rule,\\n1.50 D., axis 90\u00c2\u00b0; one month, the instrument gave exactly the\\nsame reading again.\\nTest cards and trial lenses. Twelve days,\\nL. V. 1^ W. 4- 11 D. 1.50 D. cyl., 90\u00c2\u00b0.\\nOne month, the ophthalmometer gives the same reading as\\nat first.\\nL. V. 1^ W. 4- 11 D. 1.50 D. cyl., 90\u00c2\u00b0.\\nReads Jaeger No. 1 at 10 inches with 5 D. added.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0348.jp2"}, "349": {"fulltext": "ILLUSTRATIVE CASES 331\\nThe ophthalmoscope and oblique illumination show a clear\\npupil. Both the distance and reading glasses were ordered.\\nTilting the glasses in this case improved the vision very\\nlittle, if any, since the astigmatism was in the horizontal merid-\\nian and the cylinder was worn with its axis at 90\u00c2\u00b0. I have\\nfound the same thing true many times when the axis of the\\ncylinder was several degrees distant from the horizontal merid-\\nian, for example, the case immediately preceding this one.\\nCase CXXIII. Astigmatism against the rule, 3 i three\\nweeks after operation 1 _Z)., six weeks after operation No cylin-\\nder accepted on the final test. September 21, 1891, George H.,\\naged fifty years, in good health, had a simple extraction of\\ncataract from the right eye by Dr. Emerson. The operation\\nwas without complication, and the patient was discharged at\\nthe end of three weeks.\\nOphthalmometer. Three weeks, astigmatism against the\\nrule, 3 D., axis 180\u00c2\u00b0 four weeks, 2.50 D., axis 180\u00c2\u00b0 six\\nweeks, 1 D., axis 180\u00c2\u00b0.\\nTest cards a7id trial lenses. Three weeks,\\nR. V. f W. 10 D. 2.50 D. cyl., 180\u00c2\u00b0.\\nOphthalmoscope and oblique illumination show a clear\\npupil.\\nSix weeks, astigmatism equals ID., axis 180\u00c2\u00b0.\\nR. V. =f^W. +11D.\\nReads Jaeger No. 1 at 12 inches with 15 D. No cylin-\\ndrical glass was accepted on this final test. Ordered botli the\\ndistance and reading glasses.\\nA slight tilting forward of the upper edge of the spherical\\nglass in this case made the vision better than with the com-\\nbination of any cylinder. Moreover, as the astigmatism was\\nexactly in the vertical meridian, and against the rule, a simple\\ntilting of the sphere on the horizontal axis was easil}^ made.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0349.jp2"}, "350": {"fulltext": "332 THE REFRACTIOX OF THE EYE\\nCase CXXIV. Astigmatism of very large amount^ 16 i\\nagainst the rwie, tivo and one-half tueeks after operation; 4 D.,\\nthree months after operation; Patient accepts 3.50 D. cylinder\\nivith proper sphere and gets F after three months. May 28,\\n1891, Bridget M., aged fifty-five years, in good health, had a\\nsimple extraction of cataract from the right eye by Dr. Emer-\\nson. The operation was without complication, and the patient\\nwas discharged two and one-half weeks after the operation.\\nOphthalmometer. Two and one-half weeks, astigmatism\\nagainst the rule, 16 D., axis 180\u00c2\u00b0; three months, 4 D., axis 180\u00c2\u00b0.\\nTest cards and trial lenses. Two and one-half weeks,\\nR. V. 2V0 6 D. 12 D. cyl., 180\u00c2\u00b0.\\nThe ophthalmoscope and oblique illumination showed a\\nclear pupil.\\nThree months,\\nR. Y. 11 \\\\y. 12 D. -I- 3.50 D. cyl., 180\u00c2\u00b0.\\nReads Jaeger No. 1 at 12 inches with 4 D. added.\\nBoth the distance and reading glasses were ordered.\\nThe very large amount of astigmatism, 16 D., in this case,\\nwas reduced to 4 D. in the course of three months time. It\\nwas on account of this very large amount of astigmatism that\\nwe waited longer than usual before giving the final test, in\\norder that it might be reduced to its lowest amount.\\nOn the first test the patient accepted -f 12 D. cylindrical\\nglass and only H- 6 D. spherical glass while at the final test\\nthe patient accepted -f 12 D. spherical glass, and only 3.50\\nD. cylindrical glass.\\nThis illustrates a common occurrence after cataract extrac-\\ntion to wit, that as the cylinder diminishes in strength, the\\nsr)here, as a rule, increases in strength, and vice versa.\\nIt may be asked how it was possible to measure so much\\nastigmatism (16 D.) with the Javal ophthalmometer, when the", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0350.jp2"}, "351": {"fulltext": "ILLUSTRATIVE CASES 33B\\ngraduated mire has only eight steps on it, representing but\\n8 D. In such a case as this, it is necessary to note the posi-\\ntion of the mires on the arc, which has diopter marks on its\\nposterior edge, in the primary position and then again in the\\nsecondary position after the images have been made to touch\\nagain. The difference between the two numbers will give the\\nnumber of diopters of astigmatism.\\nSay the movable mire (in the instrument with the single\\nmovable mire, the old one) stands at 26 in the horizontal merid-\\nian when the images of the mires touch 26 added to 20 (20\\nbeing the distance in diopters the fixed mire stands on the oppo-\\nsite side of the arc) equals 46 D., the refractive power of the\\ncornea in the horizontal meridian. Then when the arc is turned\\nto 90\u00c2\u00b0, say the images separate, showing astigmatism against the\\nrule, and that the movable mire has to be moved along the arc\\ntill it stands at 10 before the images touch again. This added\\nto 20, the distance of the fixed mire, would give 30 D., the\\nrefractive power of the cornea in the vertical meridian. Now\\nthe difference between 46 and 30 D. 16 D., the difference in\\nrefractive power of the two principal meridians, or the amount\\nof the astigmatism.\\nCase CXXV. Astigmatism of large amount^ 15 i against\\nthe rule, three weeks after the operation; Reduced to 13 D. after\\ntwo months, and only to 12 I), after one year and a half leaving\\n12 D. astigmatism permanently Patient accepted 11.50 B.\\ncylinder combined with 4 D. sphere Axis of the astigmatism did\\nnot change in the first two months, hut had made a change of 15\u00c2\u00b0\\nwhen seen in eighteen months. March 16, 1891, Julia G., aged\\nseventy-seven, in good health, had a simple extraction of\\ncataract from the left eye by Dr. G. M. Black.^ The opera-\\ntion was without mishap, but during the course of healing the\\nwound pulled open twice, and when finally healed there Avas a\\n1 Ex-House Surgeon, Manhattan Eye and Ear Hospital.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0351.jp2"}, "352": {"fulltext": "334 THE REFRACTIOX OF THE EYE\\ndeeply grooved scar at the site of incision. Pupil circular and\\ncentral, but at time the patient was discharged, twenty-first\\nday, there was a membrane in it. One month after the opera-\\ntion a needling was performed by Dr. Black, which was not\\nsuccessful, and three days later a second needling was done,\\nthis time leaving a clear pupil.\\nOphthalviometer. Three weeks, astigmatism against the\\nrule, 15 D., axis 165\u00c2\u00b0; two months, 13 D., axis 165\u00c2\u00b0; eighteen\\nmonths, 12 D., axis 180\u00c2\u00b0.\\nThe ophthalmoscope showed an opening in the membrane in\\nthe pupil 3 mm. long by 2 mm. broad pupil central and\\n\u00e2\u0096\u00a0circular.\\nTest cards and trial lenses.\\nOne month, L. V. ^Vo W. 3 D. 12 D. cyl., 165\u00c2\u00b0.\\nTwo months, L. V. W. 4 D. -f- 11.50 D. cyl., 165\u00c2\u00b0.\\nOn account of the very large amount of astigmatism pres-\\nent, due to the grooved wound, distance glasses only were\\nordered, -f 4 D. +11.50 D. cyl., 165\u00c2\u00b0, and she was told to\\ncome for another test in four months. She returned after\\nsixteen months, saying the glasses had been satisfactory until\\nthe last three months.\\nThe ophthalmometer showed the astigmatism at this time,\\neighteen months after the extraction, to be 12 D., axis 180\u00c2\u00b0, in-\\nstead of 165\u00c2\u00b0, as at first. There is still a decided groove at the\\nupper margin of the cornea.\\nTest cards and trial lenses.\\nL. y. 1^ W. 6.50 D. 10.50 D. cyl., 180\u00c2\u00b0.\\nReads Jaeger No. 1 at 9 inches, with 11 D. +10. D.\\ncyl., 180\u00c2\u00b0. Both the distance and reading glasses were ordered.\\nIt will be seen that the vision with this last glass was in-\\ncreased to while 1^ was the best vision to be obtained\\ntwo months after the operation. Furthermore, the axis of the\\nglass had to be changed 15\u00c2\u00b0.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0352.jp2"}, "353": {"fulltext": "ILLUSTRATIVE CASES 335\\nThis change in the axis of the astigmatism did not take\\nplace until after two months following the operation. This I\\nhave seen in but one other case so long after the extraction.\\nIt will be noticed, too, that the strength of the spherical glass\\nhad to be increased as the strength of the cylinder was dimin-\\nished, a point already noted above in other cases.\\nAn 11.50 D. cylinder is the strongest cylindrical glass that I\\nhave ever seen worn but in this case it gave the best vision,\\nand I did not hesitate to order it. Even eighteen months after\\nthe operation, 10.50 D. cylinder for distance, and 10 D.\\ncylinder for reading, in combination with spheres, had to be\\nordered.\\nDr. Pfingst, already quoted, said that in his series of fifty\\ncases none accepted more than a 6 D. cylinder, although in\\nsome of his cases the instrument showed as much as 22 D. of\\nastigmatism shortly after extraction. This case, it will be seen,\\naccepted a much stronger cylinder, and, moreover, Avore it with\\ncomfort. It is an exceedingly rare case, however. But the\\nnext following case to be reported is even more remarkable as\\nto the strength of cylinder accepted, 16 D. cyl., 15\u00c2\u00b0, twenty-six\\ndays after the extraction. This glass was not given perma-\\nnently. The large amount of astigmatism was due to folding\\nof the iris along the whole length of the wound.\\nCase CXXVI. Astigmatism of excessive amount^ 20 D.,\\nagainst the rule, from incarceration of the iris in the around\\nduring healing; Patient accepted 16 D. cgL, without a)iy\\nsphere, tweyity-six days after extraction. January 17, 1891,\\nR. S. D., aged seventy-tliree years, general health good, had\\na simple extraction of cataract from the right eye b} Dr. Roosa.\\nTwo or three drops of vitreous w^ere lost at time of the opera-\\ntion. During the healing process the upper half of the iris\\nfolded backward, the pupillary edge coming in contact with the\\nciliary body, Avhile the upper or fokled portion of the iris\\nbecame incarcerated in the whole length of the wound, prevent-", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0353.jp2"}, "354": {"fulltext": "336 THE EEFRACTION OF THE EYE\\ning the wound from healing smoothly. The patient was dis-\\ncharged after twenty-six days.\\nOphthalmometer. Twenty-sixth day, astigmatism against\\nthe rule, 20 D., axis 15\u00c2\u00b0.\\nTest cards and trial lenses.\\nR. V. 2V0 cyi- 15\u00c2\u00b0.\\nOphthalmoscope and oblique illumination show a membrane\\nin the pupil. The pupil is drawn upward so far that it looks\\nas if an iridectomy had been done above.\\nThis patient was instructed to return in a month to have a\\nneedling performed, but he did not come again, and he has\\nbeen lost sight of. In regard to the excessive amount of\\nastigmatism in this case, and the very strong cylinder accepted,\\nit is fair to presume that the astigmatism did not diminish a\\ngreat deal after the patient went from under observation;\\nbecause the measurements were made on the twenty-sixth day\\nafter extraction, about one month, after which length of time\\nthe astigmatism, as a rule, changes but little, and after six\\nweeks time practically none.\\nA 16 D. cylinder is by far the strongest cylinder I have\\never seen accepted. But this glass in the present case gave\\nthe best vision to be obtained. I would call to mind again,\\nhowever, the case of Dodd (eye not aphakial), v/here he gave\\n28 D. as a cross-cylinder, as follows\\n12 D. cyl., 95\u00c2\u00b0 -f 16 D. cyl., 5\u00c2\u00b0.i\\n1 The patient who accepted this phenomenal glass had had trachoma, and V..\\nwithout correction was only The ophthalmometer showed astigmatism\\nagainst the rule, 28 D., axis 5\u00c2\u00b0 or 95\u00c2\u00b0 The refractive power of the cornea\\nin the meridian at 5\u00c2\u00b0 was 60 D., and in the meridian at 95\u00c2\u00b0, 32 D. an excess in\\npower of 17 D. in the meridian at 5\u00c2\u00b0, and a deficiency of 11 D. in the meridian\\nat 95\u00c2\u00b0, from the average refractive power of the cornea, which is about 43 D.\\nThe patient had in addition to the mixed astigmatism (which was corneal) 5 D.\\nof hypermetropia. This corneal correction 17 D. cyl., 95\u00c2\u00b0 11 D. cyl.,\\n5\u00c2\u00b0), added to an hypermetropia of 5 D. 12 D. cyl., 95\u00c2\u00b0 16 D. cyl., 5\u00c2\u00b0),.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0354.jp2"}, "355": {"fulltext": "ILLUSTRATIVE CASES 337\\nCase CXXVII. Astigmatism of very large amount^ 22 D.\\nagainst the rule^ two weeks after operation; 5 D. against the rule\\nfive months after ojjeration^ at ivhich point it remained stationary\\nChange in axis of 10\u00c2\u00b0 during healing. February 19, 1898,\\nAnn F., aged fifty-five, in good health, had a simple extraction\\nof cataract from the left eye by me at the Manhattan Eye and\\nEar Hospital. The eye healed quickly, but on the seventh day\\nthe patient fell over backwards from a stool on which she was\\nsitting and pulled the wound open. This healed again, but left\\na deeply grooved wound. The patient was discharged on the\\nseventeenth day pupil central and circular.\\nOphthalmometer. Seventeenth day, astigmatism against\\nthe rule, 22 D., axis 180\u00c2\u00b0; one month, 12 D., axis 170\u00c2\u00b0; five\\nmonths, 5 D., axis 170\u00c2\u00b0 one year, 5 D., axis 170\u00c2\u00b0.\\nTest cards and trial lenses.\\nSeventeen days, L. y. -52_o_. ^y. 4_ 8 D. 8 D. cyl., 180\u00c2\u00b0.\\nOne month, L. V. |f W. 10 D. 8 D. cyL, 170\u00c2\u00b0.\\nFive months, L. V. W. 12 D. 3.50 D. cyL, 170\u00c2\u00b0.\\nJaeger No. 1 at 12 in., with 16 D. 3 D. cyl., 170\u00c2\u00b0.\\nOrdered both the distance and reading glasses. This patient\\nwas seen one year after the extraction, and the astigmatism\\nhad not changed after the first five months. Twenty-two\\ndiopters is the highest amount of astigmatism after a cataract\\nextraction I have ever seen. Although the ophthalmometer\\nregistered this very great amount of astigmatism, at no time\\nwould the patient accept more than an 8 D. cyl.\\ngave the immense improvement in vision or 15-fold Letter tlian the vision\\nwithout the glass.\\nWith his glasses the patient could read newspaper print and follow his trade,\\nthat of a shoemaker. The doctor remarked on the case that without the ophthal-\\nmometer he could not have fitted it correctly, because subjective tests alone,\\nor even with the aid of the ophthalmoscope and retinoscopo, would have been\\nalmost useless, in which I agree with him.\\nFor a full report of the case, see Ophthalmic Bccord, Vol. V, p. 220.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0355.jp2"}, "356": {"fulltext": "338 THE REFRACTION OF THE EYE\\nCase CXXVIII. Astigmatism against the rule, 3D., twa\\nand one-half weeks after operation; Astigmatism with the rule,\\n2 D., three months after operation, which remained as such for\\nabout four years, ivhen the patient ivas last seen; Ophthalmometer\\nshowed no cor7ieal astigmatism whatever before the extraction.\\nJanuary 29, 1891, H. R. N., aged seventy-one years, in good\\nhealth, had extraction of cataract, with iridectomy, from the\\nleft eye by Dr. Lewis. A mild iritis followed the extraction,\\nbut the patient made a good recovery, and was discharged on\\nthe eighteenth day.\\nOphthalmometer. Two and one-half weeks, astigmatism\\nagainst the rule, 3 D., axis 180\u00c2\u00b0 three months, astigmatism with\\nthe rule, 2D., axis 90\u00c2\u00b0; and three and one-half years later the\\nastigmatism was the same exactly as to amount and axis.\\nTest cards and trial lenses. Two and one-half weeks,\\nL. V. f^ W. 10 D. 1 D. cyl., 180\u00c2\u00b0.\\nOphthalmoscope and oblique illumination showed a light\\nmembrane in the pupil. This was needled three months later.\\nAt time of needling the ophthalmometer showed that the astig-\\nmatism had changed from 3 D. against the rule to 2 D. with\\nthe rule, axis 90\u00c2\u00b0. August 7, 1894, over three and one-half\\nyears later, the corneal astigmatism still remained 2D., with the\\nrule, and\\nL. V. II W. -f 9 D. -f- 1 D. cyl., 90\u00c2\u00b0.\\nJaeger No. 1 at 12 inches, with -f 16 D. spherical glass.\\nCase CXXIX. Astigmatism against the rule, 10 D., four\\nweeks after operation; Six months after operation, astigmatism\\nu ith the rule, 4.50 D., which four Quonths later (^and ten months\\nafter operation) had diminished to about 1 D. with the rule.\\nApril 6, 1891, Phoebe W., aged fifty-five years, in good health,\\nafter a preliminary iridectomy, had extraction of cataract\\nfrom the right eye by Dr. Roosa. Iritis followed, moderately", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0356.jp2"}, "357": {"fulltext": "ILLUSTRATIVE CASES 339\\nsevere. The patient was discharged on the twenty-eighth\\nday.\\nOphthalmometer. Four weeks, astigmatism against the\\nrule^ 10 D., axis 180\u00c2\u00b0; six months, astigmatism with the ruley\\n4.50 D., axis 75\u00c2\u00b0.\\nTest cards and trial lenses. Four weeks,\\nR. V. W. 13 D. 8 D. cyl., 180\u00c2\u00b0.\\nOphthalmoscope and oblique illumination show a membrane\\nin the pupil. Patient advised to have a needling performed,\\nbut she wished to wait some months. Six months later\\nneedling was performed, and one week after the needling,\\nR. V. 1^ W. 12 D. 2.50 D. cyh, 75\u00c2\u00b0.\\nReads Jaeger No. 1 at 10 inches, with 3.50 D. sphere\\nadded. Four months later this patient was examined by\\nDr. Lewis, and he found the astigmatism to be about 1 D.\\nwith the rule, axis 60\u00c2\u00b0; the vision had increased to W.\\n10 D. sphere, the patient not accepting any cylinder.\\nThis patient had had a cataract removed from the left e3 e,\\npreviously to the operation on the right eye, with a good result.\\nThe case is reported to show the remarkable change in the\\nastigmatism that occurred in less than a year s time.\\nCase CXXX. Astigmatism with the rule^ 4.50 D., three\\nand one-half weeks after operatio7i Changed to 1.50 D. against\\nthe rule^ after three years^ and remained thus at the end of five\\nyears from operation; Case remarkable also for aciiteness of\\nvision obtained, and for accommodative po2cer after the e.r-\\ntraction of the lens. January 27, 1894, Emil C, aged forty-\\ntwo years, in good health, had extraction of a black cataract,\\nwith iridectomy, from the right eye by me at his home. The\\nwound did not heal completely for a week, and only a very\\nshallow anterior chamber formed, but at the end of the week\\nthe wound closed completely, and the eye recovered with the", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0357.jp2"}, "358": {"fulltext": "340 THE REFRACTIOX OF THE EYE\\nremarkable vision of (Snellen). At the end of three months\\nit was discovered that he had the power of accommodation in\\nthe e3 e and for that reason the case was reported at length in\\nthe 3Ianliattan Eye and Ear Hospital Reports^ January, 1895.\\nHis vision at time of the operation was\\nT? Y _ 20 T Y _ 2_0\\nJaeger No. 12 at 10 inches right eye, and No. 9 at 10\\ninches left eye. Though his vision was so good by the Snellen\\ntest, he could not recognize friends or members of his own\\nfamily on the street, had not worked for five years, and insisted\\non the operation being done.\\nOphthalmometer. Before the operation, astigmatism with\\nthe rule, .50 D., axis 90\u00c2\u00b0 or 180\u00c2\u00b0 in each eye three and\\none-half weeks after the operation, astigmatism with the rule,\\n4.50 D., axis 90\u00c2\u00b0 three months after the operation no astig-\\nmatism whatever three years, astigmatism against the rule,\\n1.50 D., axis 5\u00c2\u00b0, and five years after, exactly the same as at\\nthree years, both as to the amount and axis of the astigmatism.\\nTest cards and trial lenses. Three and one-half weeks,\\nR. V. 1^ W. 4- 9 D. 4- 3.50 D. cyl., 90\u00c2\u00b0.\\nThree months, R. V. f^ W. -f 11.50 D.\\nJaeger No. 1 at 12 to 15 inches, with -f- 15.50 D.\\nThe patient discarded the reading glasses after wearing\\nthem a few weeks, and wore the distance glasses for all pur-\\nposes. With this distance glass (11.50 D.) he read |-J\\n(Snellen), and Jaeger No. 1 from 8 to 221 inches, without\\nchanging the position of the glass at all on his nose.\\nMay 6, 1897, three years and four months after the opera-\\ntion, I made the following note in my case book\\nOphthalmometer, astigmatism against the rule, 1.50 D.,\\naxis 5\u00c2\u00b0.\\nR. Y. W. 10.50. D. +1.50 D. cyl., 5\u00c2\u00b0.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0358.jp2"}, "359": {"fulltext": "ILLUSTRATIVE CASES 341\\nJaeger No. 1, with the same glass, from 8|- to 22^ inches.\\nWhen last examined, five years after the operation, the\\nastigmatism was the same as at the end of three years, and the\\npatient had vision and still the power of accommodation.\\nThe ophthalmoscope and oblique illumination showed the\\nfundus of the eye normal and the media perfectly clear. The\\npupil was oval (from iridectomy above) and free from mem-\\nbrane, except a very narrow strip at the margin.\\nCase CXXXI. Astig7natism with the rule, 3D., three weeks\\n-after operation; 1.50 D., against the rule, three months after\\nAccepts 1 D., cylindrical glass, with sphere for distance, hut no\\ncylinder for reading. November 26, 1890, M. R., aged forty-\\nfive years, in good health, had a simple extraction of cataract\\nfrom the left eye by Dr. Webster. A mild iritis occurred\\nduring healing, but the patient made a good recovery and was\\ndischarged on the twenty-third day.\\nOphthalmometer. Three weeks, astigmatism with the rule,\\n3D., axis 90\u00c2\u00b0; three months, astigmatism against the rule,\\n1.50 D., 180\u00c2\u00b0.\\nTest cards and trial lewises.\\nThree weeks, L. V. f\u00c2\u00a7 W. 8.50 D. -i- 2.75 D. cyl., 90\u00c2\u00b0.\\nThree months, L. V. f\u00c2\u00a7 W. 10.50 D. 1 D. cyl., 180\u00c2\u00b0.\\nPatient was given 14 D. for near work, and 10.50 D.\\n1 D. cyl., 180\u00c2\u00b0 for the distance.\\nThe ophthalmoscope and oblique illumination showed a clear\\npupil and media.\\nCase CXXXII. Astigmatism against the m(h\\\\ iritJi a eJunige\\nin the axis of 30\u00c2\u00b0 within one week s time, due pei-Jiaps to a stretch-\\ning of the wound from needling, which iras pe)for))ied o)ie ))io)ith\\nxfter the extraction. March 18, 1891, J. S., aged iifiy-six\\nyears, good health, had a simple extraction of cataract from the\\nleft eye by Dr. Pomeroy. The iris was wounded at time of", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0359.jp2"}, "360": {"fulltext": "342 THE REFRACTIOX OF THE EYE\\nthe operation and iritis followed. The patient was discharged\\nin one month.\\nOphtJialmometer. One month, astigmatism against the\\nrule, 4 D., axis 180\u00c2\u00b0. Five weeks, and after needling one\\nweek previously, astigmatism against the rule, 3 D., axis 30\u00c2\u00b0.\\nTest cards and trial lenses.\\nL. V. f W. 10 D. 3 D. cyl., 180\u00c2\u00b0.\\nOphthalmoscope and oblique illumination show a membrane\\nin the pupil needling performed. One week later,\\nL. V. f^ W. 9.50 D. 2.25 D. cyh, 30\u00c2\u00b0.\\nThis patient unfortunately was not seen again at the clinic.\\nThe interesting point in the case is the marked change in the\\naxis of the astigmatism after the needling, as much as 30\u00c2\u00b0.\\nThis was due, I think, to stretching of one end of the wound,\\nthough it may have been from the uneven healing of the\\nwound.\\nCase CXXXIII. Astigmatism 6 D., axis 45\u00c2\u00b0; Section was\\nmade directly above for the extraction^ hut the nasal side of the\\nivound {left eye broke open during a needling on the twelfth day\\nUltimate vision JJ. October 8, 1890, E. B., aged fifty-three\\nyears, good health, had a simple extraction of cataract from the\\nleft eye by Dr. Webster. Xo accident during the operation,\\nand the eye did well. Twelve days later, when Dr. Webster\\nattempted to perform a needling, the patient squeezed the\\neye violently and opened the wound at the nasal extremity.\\nWithin four days the wound had healed again, but no further\\nattempt to needle was tried until five months later, when a\\nsuccessful needling was performed.\\nOj^htlialmometer. Seventeenth day, astigmatism with the\\nrule, 6 D., axis 45\u00c2\u00b0 five months, 1.50 D., axis 45\u00c2\u00b0.\\nTest cards and trial lenses. Seventeenth day,\\nL. V. -jVo W. 9 D. 6 D. cyl., 45\u00c2\u00b0.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0360.jp2"}, "361": {"fulltext": "ILLUSTRATIVE CASES 343\\nThe ophtlialmoscope and oblique illumination show a mem-\\nbrane in the pupil.\\nFive months, and after needling,\\nL. y. 11^ W. 13 D. .50 D. cyl., 45\u00c2\u00b0.\\nReads Jaeger No. 1 at 10 inches, with 18 D. sphere, with-\\nout any cylinder. Both the reading and distance glasses Avere\\nordered.\\nAs a rule, after cataract extraction, the axis of the correct-\\ning cylinder is worn horizontally with the direction of the\\nwound; but exceptionally it has to be worn with its axis at\\nright angles to the direction of the wound, as in the few cases\\nwhere the astigmatism is with the rule after the operation for\\ncataract. The usual position for the corneal section being\\ndirectly above in cases of cataract extraction, the astigmatism\\nthat follows, in the great majority of cases, is against the rule,\\nand requires the cylinder to be worn with its axis at or near\\n180\u00c2\u00b0, or horizontally with the direction of the corneal section.\\nThe exceptions to this general rule are: First, where there has\\nbeen a high degree of myopia, and the astigmatism is against\\nthe rule, a minus cylinder must be worn to correct the astigma-\\ntism, when the axis of the cylinder must be worn at or near\\n90\u00c2\u00b0, or at right angles to the corneal section second, where the\\nastigmatism is with the rule after extraction, when the cyl-\\ninders must be worn at or near 90\u00c2\u00b0, or at right angles to the\\ncorneal section.\\nIn the case last reported the section was directty above, but\\nduring an attempted needling the patient squeezed the eye\\nviolently and pulled the Avound open at its nasal end (at a\\nmeridian near 135\u00c2\u00b0), and the grooved wound that followed at\\nthis position caused the axis, or the meridians of greatest and\\nweakest curvature, to be at 45\u00c2\u00b0 and 135\u00c2\u00b0 respectively. The\\nophthalmometer showed this to be so.\\nIn makinq; the section for cataract extraction, tlierefore^", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0361.jp2"}, "362": {"fulltext": "844 THE REFRACTION OF THE EYE\\nunless some special reason comes to bear on tlie case, it should\\nalways be made directly above. The astigmatism that follows\\nis usually in or near the vertical and horizontal meridians, and\\nin nearly every case against the rule. We have already pointed\\nout the advantage of tilting the strong plus spheres if the\\nastigmatism is against the rule and affects the vertical merid-\\nian. If the astigmatism does not lie in the vertical meridian,\\nor one near it, this tilting of the strong spheres is not of much\\nadvantage hence, since we can in a measure determine the axis\\nof the astigmatism after extraction by the location of our\\nsection, we should place it, as is usually done, directly above\\nthe most favorable position.\\nOf course, the section for cataract extraction could be\\nplaced below, but the surgical and optical reasons against this\\nare quite apparent. Even in making section for iridectomy\\nin glaucoma we should, where it is possible, always make the\\nsection above. First, for the reasons given above as to the\\nfavorable form of astigmatism it causes second, and most im-\\nportant, by the iridectomy being made above the coloboma in\\nthe iris is hidden almost completely by the upper lid,- thereby\\ncausing less deformity and giving better vision by cutting off\\nthe excess of light and preventing diffusion circles, which\\nwould follow if the artificial pupil was made below where it\\ncould not be covered.\\nSome regard must be had, therefore, to the position of the\\nsection in cataract extraction, if we wish to do the best by\\nour patients. Astigmatism with oblique axes, that is, with the\\nchief meridians off from 90\u00c2\u00b0 and 180\u00c2\u00b0, other things being equal,\\nis always worse than the astigmatism where the vertical and\\nhorizontal meridians are at fault. Consequently, where we\\nhave a controlling influence on the axis of the astigmatism, we\\nshould exert it to the best advantage, and place it as near as\\npossible in the vertical and horizontal meridians of the cornea.\\nThere is one other class of cases of which I wish to speak", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0362.jp2"}, "363": {"fulltext": "ILLUSTRATIVE CASES\\n345\\nbriefly before closing this chapter I mean cases of myopia\\nwith cataract.\\nDr. PercivaP says some operators have expressed great\\nsurprise at the marked change in the refraction in such cases\\nafter cataract extraction, when, as a matter of fact, they should\\nexpect it. For instance, after the statistics given by Helm-\\nholtz, Bonders, and others, he shows by calculation that an\\naxial myopia of between 25 D. and 26 D. is entirely corrected\\nby simply extracting the lens from such an eye.\\nSince it requires about 11 D. to correct the emmetropic\\neye after cataract extraction, it would naturally be supposed\\nthat a myopia of 26 D., after cataract extraction, would require\\na lens representing the difference between 26 D. and 11 D.\\n15 D.) to correct it for the distance. But such is not the\\ncase, and Dr. Percival, after giving a table of such cases,\\nremarks\\nIt will be noticed that the change in refraction due to the\\noperation increases with the previous degree of axial myopia.^^\\nIn other words, the higher the degree of myopia before the\\noperation, the greater the influence proportionally will the ex-\\ntraction of the cataract have on the correction of same. I repro-\\nduce, in part, his table. The length of the emmetropic eye in\\nthis table is 22.8 mm.\\nTable\\nAnteeo-Postkeior\\nDimension,\\nOE Optic Axis\\nPowEE OF Glass\\nTO COEEECT\\nBEFOEE OpEEATION\\nPowee OF Glass\\nTO COEKECT\\nAFTER Extraction\\nChange in\\nEefkaction\\n23 mm.\\n.50 D.\\n11.2 D.\\n11.7 D.\\n26 mm.\\n9.9 D.\\n7. D.\\n10.9 D.\\n29 mm.\\n19.2 D.\\n2.9 D.\\n22.1 V\\n32 mm.\\n28.50 D.\\n1.25 P.\\n27.3 V).\\nKnapp s Archives of Ophthalmology, Bd. Vol. XXVI, pp. 1-4.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0363.jp2"}, "364": {"fulltext": "346 THE REFPtACTIOX OF THE EYE\\nI give this table in order that those who are not acquainted\\nwith the facts in such cases, as regards the change of refraction\\nby extraction of the lens from myopic eyes, may not make\\nerrors in correcting them and so that they will not be at a\\nloss to account for so marked a change in the refraction.\\nMoreover, it may prove of value, and serve as a warning also,\\nperhaps, to those who intend to, or do now, remove the trans-\\nparent crystalline lens in high degrees of myopia.\\nI have never removed the transparent lens in the living sub-\\nject, but those who advocate it claim that it can be safely done\\non suitable eyes and that the eye, by the operative procedure,\\nremains only slightly myopic, or may be rendered hyperme-\\ntropic. They also claim that visual acuity is increased by the\\nretinal images becoming larger, that the strain of convergence\\nis lessened, and that congestion of the fundus is relieved.\\nCertainly, some very favorable reports of cases of high degree\\nof myopia treated by removal of the crystalline lens have been\\nmade in the last few years. However, while keeping in mind\\nthe advantages of this method of treatment of high myopia,\\nwe should not forget the contraindications and dangers of the\\noperation.\\nContraindications. (1) Any degenerative changes in the\\nchoroid or retina, especially if these changes are near the\\nmacula (2) Vitreous opacities, which usually indicate de-\\ngenerative changes in the blood vessels (3) Marked corneal\\nopacities (4) Myopia of less than 12 D. (5) Any condition\\nthat contraindicates extraction of senile cataract, as trachoma,\\ndetachment of the retina, advanced age, etc.\\nThe chief dangers of the operation itself are (1) Intra-\\nocular hemorrhage (2) Detachment of the retina.\\nWhen we consider that one of the contraindications to the\\noperation is a myopia of less than 12 D., and another, and the\\nmost serious one, degenerative changes in the choroid and\\nretina, and remember how few eyes there arp with myopia of", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0364.jp2"}, "365": {"fulltext": "HIGH MYOPIA WITH CATARACT 347\\nmore than 12 D., with sound fundi, it will be apparent how few\\nreally suitable eyes there are for the operation. Furthermore,\\nto obtain that ideal condition, about 2 D. of myopia remaining\\nafter the operation, so that the patient would not need a glass\\nfor the near point, the eye must have had at least 30 D. of\\nmyopia before the operation. Now 30 D. of myopia is so rare\\nas hardly ever to be met with, and Avhen it is encountered,\\ndegenerative changes in the fundus are almost certain to be\\npresent in such a highly myopic eye, which contraindicate\\noperative procedure. Hence the ideal sought for in these cases\\nis clearly out of the question, theoretically at least, as shown\\nby the table of Percival. Even to obtain emmetropia after the\\noperation, theoretically, a myopia of 25 or 26 D. is necessary\\nbefore the operation. Practically, as shown by Von Hippel\\nand others, emmetropia may be obtained by extracting the lens\\n(discission of course) in myopia of only 15 D. and in myopia\\nof 18 to 20 D., it is obtained in about 25 per cent of the cases.\\nThe operative treatment of high degrees of myopia by the\\nremoval of the crystalline lens is still on trial, and time and\\nexperience must decide for or against it.\\nf", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0365.jp2"}, "366": {"fulltext": "CHAPTER XI\\nEXCEPTIONAL CASES\\nBy exceptional cases, I mean cases in which the result of\\nsubjective examinations of the visual power differs widely\\nfrom the reading of the ophthalmometer, either as to the axis\\nor amount of the astigmatism, or as to both, as found by sub-\\njective examination with the test cards and trial lenses. All\\ncases wherein the reading of the instrument differs as much as\\n15\u00c2\u00b0, as regards the axis, and as much as ID. as regards the\\namount (except after cataract extraction) of the astigmatism,\\nas found by subjective and by other objective tests, I regard\\nas exceptional. Such cases, in my experience, are relatively\\nrare, and hence I regard them as exceptional.\\nJaval, as far back as 1882, in the examination of over one\\nhundred eyes, found the total and the corneal astigmatism was\\nthe same except in four cases. But further and more extensive\\nexaminations since then have established the fact that the\\ncorneal astigmatism as measured by the ophthalmometer, and\\nthe total astigmatism, differ in amount to the extent of about\\n.50 to .75 D. in the great majority of cases. When the corneal\\nastigmatism is with the rule, the total astigmatism is found\\nto be less than the corneal by .50 to .75 D., and when the corneal\\nastigmatism is against the rule, the total astigmatism ia\\nfound to be more than the corneal by .50 to .75 D. The axis of\\nthe total astigmatism usually coincides with that of the corneal,\\nor to within 10\u00c2\u00b0. Keeping these points in mind, and taking into\\naccount the amount of difference to be expected between the\\ncorneal and the total astigmatism, the subjective examination is-\\nmade easy and satisfactory. In fact, as a general practice, in\\n348", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0366.jp2"}, "367": {"fulltext": "EXCEPTIONAL CASES 349\\npatients forty years of age and over, a single test with the\\nophthalmometer and a subsequent test with test cards and trial\\nlenses is quite sufficient examination in order to arrive at the\\nright glasses to be given, and, of course, without a mydriatic.\\nIn patients under forty years of age, two tests, as a rule, are\\nenough, and seldom is it necessary to give three, even in cases\\nof children, and then without a mydriatic, except in rare in-\\nstances where spasm of accommodation is present (strabismus\\ncases are, of course, here excluded). It has been my experience,\\ntaking cases as they come, that I get better results without\\na mydriatic than with it (with the exception above noted).\\nThe mydriatic, besides upsetting the natural relation between\\nthe accommodation and the convergence, often causes us to\\ngive the patient. too strong a glass, and one which he will often\\nnot wear after coming from under the influence of the mydriatic.\\nTherefore, except in cases of excessive and irregular action\\nof the ciliary muscle (spasm of accommodation), I believe the\\npractice of using mydriatics a bad one, and one to be avoided.\\nMy experience in thousands of cases has taught me this.\\nBut even with careful testing by an experienced hand, both\\nwithout and with a mydriatic, there are a few cases where the\\nastigmatism indicated by the ophthalmometer differs widely\\nfrom that found by further objective and subjective examina-\\ntion. Where such discrepancies occur, they are to be ac-\\ncounted for by one or more of the following causes\\n1. Error in observation.\\n2. Abnormal lenticular astigmatism, from whatever cause.\\n3. Position of the glasses in front of the eyes.\\n4. Angle alpha^ and lack of centering of the cornea and\\nthe lens.\\n5. Astigmatism of the posterior surface of the cornea.\\n6. Contraction of the recti muscles.\\n7. Spherical aberration.\\n8. Imperfect instruments.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0367.jp2"}, "368": {"fulltext": "\u00e2\u0096\u00a0i\\n350 THE REFRACTIOX OF THE EYE\\n1. Faulty observation. The discrepancy between the read-\\ning of the instrument and the astigmatism as found on subjec-\\ntive examination, which is due to faulty observation, of course\\nis onl}^ an apparent one and a second and more careful ex-\\namination usually clears it up. A poor light or uneven posi-\\ntion of the head in the head-rest accounts for many of these\\nmistakes in observation. Again, and especially in the aged, or\\nin case of cliildren who have been crj^ing, tears standing in the\\neyes often cause an incorrect estimate to be made. In fact,\\nsometimes when the astigmatism is with the rule, if of small\\namount, it may appear to be against the rule. This seems to be\\nbrought about by the tears standing in the groove between the\\nlower eyelid and the eyeball and encroaching on the lower half\\nof the cornea. The anterior surface of the tears between the\\nedge of the eyelid and cornea assume a concave shape, lessen\\nthe refraction of the cornea in the vertical meridian, and cause\\nthe instrument to read astigmatism against the rule, when\\nthere is actually a small amount of astigmatism with the rule.\\nWhere the astigmatism is of considerable amount and with the\\nrule, it would be lessened to some extent by this cause and if\\nagainst the rule, increased to some extent.\\nThat the tears can modify the refractive power of the eye\\nthere is no question, because, strictly speaking, the tears form\\nthe first refractive surface of the eye, since there is always a\\nthin layer of tears on the front of the cornea to keep it moist.\\nBut this layer is so thin and in such close contact with the\\ncornea, and moreover, having about the same index of refrac-\\ntion of the cornea, its influence is so weak that it may, as a rule,\\nbe neglected entirely (Hirschberg, Ceiitralhl. fur med. Wi%-\\nsensch.., 18T4). However, when the tears collect in excess in\\nthe eye, so as to encroach upon the lower half of the cornea,\\nthey may materially affect the reading of the ophthalmometer.\\n2. Lenticular astigmatism. Javal, Nordenson, Schiotz, and\\nmany observers since them, have established the fact that", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0368.jp2"}, "369": {"fulltext": "LENTICULAR ASTIGMATISM 351\\nlenticular astigmatism amounts as a rule to .50 to .75 D. This\\nmay be called tlie normal astigmatism of the lens, just as we\\nhave about the same amount of astigmatism normally present\\nin the cornea. In fact, the two, as a rule, neutralize each\\nother. The lenticular astigmatism may amount to 1 or 1.50 D.,\\nor even to 2D., and, in rare exceptions, to even more. In a\\ncase of lenticonus anterior in my practice, reported in this chap-\\nter, it amounted to as much as 7.50 D! But this is a very rare\\ncase, only five or six cases of lenticonus anterior having been\\nreported in all literature thus far.\\nJaval 1 has reported a case of lenticular astigmatism of 2D.;\\nCarl Weiland,^ a case with similar amount; and George M.\\nBlack, a lenticular astigmatism of 3.50 D. But all of these\\nare exceptional cases. The lenticular astigmatism, as a rule,\\namounts to but .50 to .75 D., as proved by abundant statistics,\\nwhereby it is shown that, in actual practice, the corneal astig-\\nmatism is diminished or increased that amount, accordingly as\\nthe astigmatism is with or against the rule. The most reason-\\nable explanation to be given for the necessity of deducting .50\\nto .75 D. from the reading of the instrument when the astigma-\\ntism is with the rule, and adding a like amount when the astig-\\nmatism is against the rule, is in the following assumption, to\\nwit That, in corneal astigmatism with the rule, there is usually\\nassociated a lenticular astigmatism of .50 to .75 D.,in the same\\nmeridian, but of an opposite kind, thereby neutralizing that\\namount of the corneal astigmatism and, in astigmatism against\\nthe rule, there is usually present a lenticular astigmatism of .50\\nto .75 D. in the same meridian and of the same kind, thereby\\nadding that amount to the corneal astigmatism.*\\n1 3Iemoires d Ophtalmometre, p. 121.\\n2 Knapp s Archives of Ophthalmology, Vol. XXII, 1893.\\n3 Loc. cit., Vol. XXI, 1892.\\nI am aware of the fact that this can be explained in another way, to wit\\nIn corneal astigmatism, with the rule, the lenticular astigmatism might be of\\nthe same kind, but in the meridian at right angles to the corneal astigmatism", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0369.jp2"}, "370": {"fulltext": "352 THE REFRACTION OF THE EYE\\nIn this place it is interesting to note how regular lenticular\\nastigmatism is caused. It may be produced by an oblique\\nposition of the lens, by a slight displacement of the lens, as\\nby sub-luxation, or by unequal curvature of its surfaces, ir-\\nregular lenticular astigmatism, together with a large amount\\nof regular lenticular astigmatism, may be caused by a marked\\ndisplacement of the lens, so that the edge of the lens lies in\\nthe pupillary space by lenticular opacities, as in beginning\\ncataract and by lenticonus. We may have also a dynamic\\nregular astigmatism produced by an unequal contraction of\\nthe ciliary muscle (Dobrowlsky, Javal).\\nBonders, in his classical book on refraction, has reported\\ntwo cases of lenticular astigmatism one (p. 532) -from con-\\ngenital eccentricity of the crystalline lens and the other case\\n(p. 536) due to an oblique position of the lens, with no, or\\nonly slight, lateral displacement of the lens.\\nI have had the pleasure of observing one such case under\\nespecially advantageous circumstances, that is, in a case of\\naniridia. Here, because of the complete absence of the iris,\\nthe lens could be seen plainly. When the patient first came\\nunder observation the lens was vertical and not displaced at all,\\nbut in the course of eighteen months it became luxated upward\\nto a slight extent (about 1^ mm.), and the upper edge of the\\nlens was tilted backward. By reason of this, while the corneal\\nastigmatism remained unchanged, the total astigmatism in the\\neighteen months increased 1.50 D. This case is reported in\\nfull farther on in this chapter.\\nin which case, if the meridian at error in both the cornea and lens were myopic\\nin nature, a simple myopia of .60 to .75 D. would be produced. In corneal\\nastigmatism against the rule (by this explanation) the lenticular astigmatism\\nmust be of an opposite kind and in the meridian at right angles to the corneal, if\\nthe total is to amount to more than the corneal. But I believe the first explana-\\ntion more likely to be the true one, and, in fact, actual measurements (Bonders)\\nand cases reported show it to be true. See Case CXXXVI in support of it.\\n1 In the full report of the case, Bonders stated also that the lens had an\\noblique position.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0370.jp2"}, "371": {"fulltext": "LENTICULAR ASTIGMATISM 353\\nAgain, lenticular astigmatism may be caused by the surface\\nof the lens being unequally curved, just as in the cornea.\\nMoreover, the principal meridians of the lens may not coincide\\nwith the principal meridians of the cornea, but respecting\\nthis, however, nothing is with certainty known. And this\\nsame observer, long ago, made measurements showing that the\\naxes of the lenticular astigmatism often did not coincide with\\nthe axes of the corneal astigmatism. Nevertheless, he came to\\nthe conclusion, -that with a Mgh degree of asymmetry of the\\ncornea asymmetry of the crystalline lens exists^ acting in such a\\ndirection^ that the astigmatism for the whole eye is nearly always\\nless than that proceeding from the cornea.^\\nIt is certain that, in almost all cases of astigmatism with\\nthe rule (and they go to make up the great majority of cases),\\nthe corneal astigmatism on the subjective examination is les-\\nsened from some cause, presumably by a lenticular astigmatism,\\nwhatever be the relative positions of the principal meridians of\\nthe cornea and the lens.\\nIn young subjects, moreover, we may have a regular astig-\\nmatism (dynamic) of the lens, produced by an unequal contrac-\\ntion of the ciliary muscle. Dobrowlsky was the first to point\\nthis out, and Javal made the same observation later.\\nSuch astigmatism is shown to exist by paralyzing the\\naccommodation with atropine, when a corneal astigmatism,\\nor part of it at least, which required no correction before\\nparalysis, will accept a cylindrical glass thus proving conclu-\\nsively that the corneal astigmatism must have been corrected,\\nin whole or part, by a lenticular astigmatism, which latter, as\\nboth Dobrowlsky and Javal state, is most probably due to an\\nuneven or irregular contraction of the ciliary muscle.\\nIrregidar lenticular astigmatism, together with a large\\namount of regular astigmatism, may be produced by a decided\\nluxation of the lens, so that its edge or rim lies across the\\n1 Donders, Accommodation and Iiefraction of the Eye. Loc. cit.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0371.jp2"}, "372": {"fulltext": "354 THE EEFRACTIOX OF THE EYE\\ncenter of the pupil. Luxation of the lens to such an extent\\nnot only produces irregular astigmatism, but causes diplopia\\nby the half of the lens in the pupil acting as a prism. More-\\nover, the refraction of the rays of light is so different in the\\ntwo halves of the pupil that everything is confused to the\\npatient. In such cases, it is best, as a rule, to fit the aphakial\\npart of the pupil, ignoring the half with the lens altogether, as-\\nthe best vision is to be obtained by so doing. Such strong\\nglasses blui the images completely for the part of the pupil\\nwith the lens in it, and this does away with diplopia, at least\\nfor the eyes singly, although it may be present when both eyes\\nare used together.\\nLenticular opacities, as in beginning cataract, produce\\nirregular astigmatism, and often cause diplopia. This is due\\nto the different sectors of the lens becoming unequally swollen\\nor distorted, and thereby their foci made different, with the\\nresult that diplopia, or polyopia even for one eye, is often\\ncaused. Glasses do not improve vision much or any in such\\ncases, and it is best to wait till the cataract forms, which as a\\nrule quickly follows. There are a certain number of cases of\\ndiplopia and polyopia even which are not due to lenticular\\nopacities, and which are entirely relieved by glasses. Dr. St.\\nJohn Roosa, in his recent book. Defective Eyedglit^ emphasizes\\nthis point, and reproduces some excellent figures of Dr. G. J.\\nBull s of Paris, by way of illustration. He says The double\\nvision quite often seen in hj^permetropia, or hypermetropic\\nastigmatism, a diplo|)ia which is not constant, may always be\\nrelieved by a correction of the error of refraction.\\nDr. G. J. Bull has shown that this so-called double vision\\nis often to be described as the imperfect superposition of a\\nseries of faint multiples of the original letter. I believe that\\nthis is the correct view of quite a number of cases of polyopia\\n1 The Macmillan Co. N. Y.\\n2 Trans. Oph. Soc. Unit. King., Vol. XVI, p. 204.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0372.jp2"}, "373": {"fulltext": "ANGLE ALPHA 355\\nmonocularis. It explains the ease witli which such cases are\\ntreated by correction of the error of refraction. The observer\\nwho will make himself astigmatic to a considerable degree will,\\nin an instant, recognize this doubling of vision, which is the\\nresult of an uncorrected error of refraction in the eye, and has\\nnothing to do with insufficiency of the muscles.\\nLenticonus may be the cause of irregular astigmatism, to-\\ngether with a large amount of regular astigmatism, though\\nsuch cases are exceedingly rare.\\n3. The position of the glass in front of the eye. Strictly\\nspeaking, the cylinder that corrects the astigmatism, as indi-\\ncated by the ophthalmometer, should be worn in contact with\\nthe cornea. For obvious reasons this cannot be done. Glasses\\nmust be worn about one-half inch in front of the eyes. In low\\nor moderate amounts of astigmatism, when not associated with\\na large amount of spherical error, this moving forward of the\\nglasses one-half an inch does not alter the power of the glass\\nmuch but in very high degrees of astigmatism, especially\\nwhen in addition there is a big amount of spherical error,\\npushing the glasses forward one-half inch has a great influence\\non its refractive power. This point has to be taken into con-\\nsideration, and a proper reduction in the strength of the\\ncylinder to be made on this account (see Chapter X for expla-\\nnation)\\nFor those who wish to pursue the matter further, I may\\nsay Weiland has discussed this point at length in Knapp s\\nArchives of Ophthalmology^ 1893.\\n4. Angle alpha. This angle, as it is well known, is formed\\nby the visual line and optic axis., the visual line usually cutting\\nthe cornea four or five degrees to the nasal side of the center\\nof the cornea, while the optic axis cuts the cornea at its\\ncenter.\\nNow, ordinarily, when measuring the eye for astigmatism,\\nwe do not measure the center or summit of the cornea, but a", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0373.jp2"}, "374": {"fulltext": "356 THE REFRACTION OF THE EYE\\npoint on the cornea about 5\u00c2\u00b0 to the nasal side of its center, or\\nin the point cut by the visual line. This must necessarily be\\nso, for we have the patient look directly into the center of the\\ntube, and, of course, he directs the visual line to that point.\\nTo be exact, in measuring the astigmatism of the cornea, we\\nshould find the angle alpha first in degrees, then have the\\npatient look a corresponding number of degrees to the nasal\\nside when looking toward the tube of the ophthalmometer,\\nwhen the ce^iter of the cornea would be brought into position\\nto be measured. And that the astigmatism for the two points\\nmay be different at the two points has been shown by Helm-\\nholtz, Bonders, Knapp, and others. Knapp, in his earliest\\ninvestigations to determine the shape of the cornea, in one case\\nshowed that the refractive power of the cornea in one and the\\nsame meridian at a distance of 1.25 mm. from the center of\\nthe cornea (about 7\u00c2\u00b0) varied as much as one-third diopter\\nand since the angle alpha may amount in exceptional instances\\nto as much as 12\u00c2\u00b0, it is easy to see how the astigmatism at that\\ndistance from the center of the cornea might vary from that at\\nthe center. In fact, where the astigmatism is of high amount\\nand the angle alpha large, it can be shown clinically with the\\nophthalmometer that the astigmatism varies for the two points.\\nBonders has shown that the surface of the cornea 15\u00c2\u00b0 from the\\ncenter becomes rapidly flatter from that distance on to its\\nperiphery. When using the ophthalmometer of Javal and\\n\u00e2\u0080\u00a2Schiotz, we do not measure the whole of the cornea, but only a\\nsmall spot, about 12 to 15\u00c2\u00b0 (2.50 to 3 mm.) in diameter, with\\nits center at the point on the cornea cut by the visual line. It\\ncan be readily understood that, if this point is 12\u00c2\u00b0 to the nasal\\nside of the center of the cornea, the point from which the\\nimage of one of the mires is reflected, when measuring the\\nhorizontal meridian, must be still further from the center\\nof the cornea. At such a great distance from the center\\nof the cornea, the surface is considerably flatter than at", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0374.jp2"}, "375": {"fulltext": "ANGLE ALPHA 357\\nthe center, and the error in measurement in such an instance\\nwould likely be considerable, especially if the astigmatism\\nhappened to be of high amount. Of course, it is altogether\\nexceptional to have an angle alpha of 12\u00c2\u00b0, because, as a matter\\nof fact, it rarely amounts to more than 5\u00c2\u00b0, and often not to\\nmore than 2\u00c2\u00b0 or 3\u00c2\u00b0, and may therefore, except in very high\\ndegrees of astigmatism, be left out of consideration altogether.\\nIn the higher grades of astigmatism, as after cataract extrac-\\ntion, it must be taken into account.\\nBy means of the disk of Placido on the ophthalmometer,\\nwith the degrees properly marked on it, the center of the\\ncornea is easily measured by having the patient look at\\nthe circle marked with the corresponding number of degrees\\nas the angle alpha to the nasal side when the angle is posi-\\ntive, as it usually is, and to the temporal side when it is nega-\\ntive. And this is another reason why the Placido disk should\\nnot be removed from the instrument of Javal, and replaced\\nby a plane black disk, as is now done by some instrument\\nmakers.\\nThe lack of centering, or collimation, as it is sometimes\\ncalled, of the refractive media of the eye (cornea and lens) is\\nthus seen to be exaggerated by the angle alpha, that is, by the\\nvisual line not coinciding with the optic axis, but cutting both\\nlens and cornea to the nasal side of their centers as a rule,\\nthough it may coincide with or even be to the temporal side\\nof the optic axis on rare occasions. I may say the angle gamma\\nalso increases the error caused by the angle alpha. The eye\\nwould be a much more correct optical instrument if the visual\\nline coincided with the optic axis. Even then, and after leav-\\ning out of the question axial ametropia, it would not likely be\\na perfect instrument, and that, too, on account of improper\\ncentering of its refractive surfaces. Helmholtz and Knapp\\nboth have shown that the summit of the crystalline lens does\\nnot always lie in the corneal (optic axis in practice) axis, but", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0375.jp2"}, "376": {"fulltext": "358 THE REFRACTION OF THE EYE\\nmay be as much as 2\u00c2\u00b0 to its temporal side. This, of course^\\nwould cause astigmatism.\\nThe want of proper centering of the cornea and crystalline\\nlens, and the angle alpha^ must all be put down as causes of\\ndiscrepancy in the astigmatism found by the ophthalmometer\\nand that found by subjective examination.\\n5. Astigmatism of the posterior surface of the cornea. The\\nposterior surface of the cornea may be astigmatic, just as the\\nanterior surface, rendered so by its principal meridians having\\nunequal length of radii of curvature. Tscherning has invented\\nan instrument, the ophthalmophakometer, for measuring the\\nposterior surface of the cornea, also for measuring the surfaces\\nof the lens. This instrument is described by A. Javal in\\nNorris and Oliver s System of Diseases of the Eye., Vol. 11^\\npages 135 and 136.\\nBy actual measurements, the posterior surface of the cornea\\nis shown to have a slightly shorter radius of curvature than the.\\nanterior surface. A. Javal, in commenting on the same, says\\nThe posterior surface of the cornea is found to diminish in\\ncurvature from the center toward the peripher}^, as in the case\\nof the anterior surface, and in case of corneal asymmetry it\\nappears also, as might be expected, to follow tlie asymmetry of\\nthe anterior surface. As a concave lens of asymmetrical curva-\\nture, the effect of the cornea is to compensate in some degree\\nthe astigmatism of the anterior corneal surface as measured by\\nthe ophthalmometer.\\nThe maximum compensation due to this cause, so far as\\nhas been observed, is about 1 D. (as estimated for an eye in\\nwhich the total astigmatism measured about 6 D.)\\n6. Contraction of the recti muscles. In a few cases the recti\\nmuscles can, by voluntary action, alter the corneal astigmatism.\\nI have reported one such case in the Manhattan Eye and Ear\\nHospital Rep orts., January, 1895, where the patient had a cor-\\n1 Loc. cit., p. 137.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0376.jp2"}, "377": {"fulltext": "SPHERICAL ABERRATION 359\\nneal astigmatism with the rule .50 D. which he could, by vol-^\\nuntary action of the recti muscles, increase to 2 D. in the right\\neye, and to 1.50 D. in the left eye. When under a mydriatic\\nhe could still increase the astigmatism iil the right eye to 1.50\\nD., and in the left eye to 1 D. The lids were held from the\\neye so they could have no influence.\\nThis might be called a dynamic corneal astigmatism, just\\nas we may have a dynamic lenticular astigmatism caused by an\\nunequal contraction of the ciliary muscle.\\n7. Spherical aberration. In very high degrees of astigma-\\ntism, the images of the mires are affected by spherical aber-\\nration, and on this account give too large an amount of\\nastigmatism. Leroy and Reid have dwelt upon this point,\\nand insist that the proper reduction in the amount of the\\nastigmatism, as measured by the ophthalmometer, has to be\\nmade if it is to accord closely with that found on subjective\\nexamination.\\n8. Imperfect instruments^ either hy reason of had construc-\\ntion or poor adjustment. Sometimes the instruments them-\\nselves are at fault in construction or material, and do not\\nmake correct measurements on that account. For instance,\\nbecause of a faulty adjustment of the bi-refractive prism in\\nthe telescope, I have seen the image of the mires, after having\\nbeen put accurately in line with the axis of the telescope, that\\nis, directly in the line of the crossing of the wires in the tele-\\nscope, on rotation of the telescope for the second position, go\\nnearly out of the field of the telescope, so that they could\\nhardly be seen.\\nAgain, through lack of adjusting the arc that carries the\\nmires in the position that exactly coincides with the line\\nof doubling of the bi-refractive prism, I have seen instru-\\nments in which the images of the mires could not be made\\nto line at any position whatever. This Avas because of the\\nfaulty position of the arc in regard to the line of doubliiio", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0377.jp2"}, "378": {"fulltext": "360 THE REFKACTION OF THE EYE\\nof the prism, which caused a permanent and fixed displace-\\nment of the images of the two mires in relation to each other.\\nAgain, imperfect material as regards the prisms and the\\nlenses at times make it necessary to have entirely new prisms\\nand lenses put in to replace the old ones. Moreover, I have\\nseen instruments which had very clear images at first (both\\nthe imported and the domestic), which finally became so weak\\nand dim that correct observations could not be made with\\nthem.\\nThe above eight causes of error in ophthalmometric exam-\\nination, which are here given to account for the discrepancies\\nthat are sometimes found to exist between the astigmatism as\\nmeasured by the ophthalmometer and that found on subjective\\nexamination, together with the exceptional cases herein re-\\nported, emphasize the importance of a subjective examination,\\nin all cases, after using the ophthalmometer. Although in the\\ngreat majority of cases the ophthalmometer measures the astig-\\nmatism to within .50 to .75 D., as to amount, and to within\\n5\u00c2\u00b0 as to axis, yet there are enough exceptional cases to demand\\na subjective examination in all cases. In doubtful cases we\\nmust make other objective tests besides those made with the\\nophthalmometer and ophthalmoscope, and, if need be, which\\nis seldom indeed, a mydriatic should be used, when retino-\\nscopy can be used to advantage.\\n(1) Cases showing discrepancies as to the amount of the astig-\\nmatism.\\nCase CXXXIV. Corneal astigmatism^ 2.50 D., icith the rule;\\nTotal astigmatism^ 1.25 i hy subjective examination. Mrs.\\nH. H., aged thirty years, in good health, has worn glasses for\\nthree or four years, consulted me on September 21, 1896, on\\naccount of headaches and pains in the eyes, especially after\\nusing the eyes for close work.\\nOphthalmometer. Astigmatism with the rale, 2.50 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 in each qjq.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0378.jp2"}, "379": {"fulltext": "EXCEPTIONAL CASES 361\\nTest cards and trial lenses.\\nR. V. 1^ W. 1.25 D. cyl., 180\u00c2\u00b0.\\n=U U 1-25 D. cyl., 180\u00c2\u00b0.\\nReads Jaeger No. 1 from 1 to 15 inches.\\nOphthalmoscope, Em. at 180\u00c2\u00b0 and M. 1.50 D. at 90\u00c2\u00b0 in\\neach eye.\\nA second and a third test did not change the glass, and the\\npatient would not accept a stronger cylinder with improve-\\nment in vision. I had this patient under observation for more\\nthan two years, and when last seen the glasses were satisfactory\\nand the patient using the eyes with comfort.\\nIn this case 1.25 D. had to be deducted from the corneal\\nastigmatism as measured by the ophthalmometer, or, what\\namounted to the same thing, the patient would not accept the\\ncylinder to correct the astigmatism, as indicated by the instru-\\nment, by 1.25 D.\\nCase CXXXV. Corneal astigmatism with the rule, 1 D.\\nright and 1.50 D. left eye. Patient will accept no cylindrical\\nglass; Antimetropia Presbyopia. December 19, 1898, Mrs.\\nK. E. H., aged forty-three years, in robust health, has never\\nworn glasses, though she has seen poorly with the right eye\\nsince a child. She comes now for reading glasses.\\nOphthalmometer. Astigmatism with the rule, 1 D. 90\u00c2\u00b0 -1-\\nor 180\u00c2\u00b0 right eye, 1.50 D. 90\u00c2\u00b0 or 180\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nR V -2JL w 13 D\\n200 100\\nL. V. 1^ will accept no glass.\\nReads Jaeger No. 1 from 8 to 20 inches, with +1.25 D.\\nsphere left eye no single binocular vision, the patient using\\nthe left eye for both the distance and the near point.\\nOphthalmoscope. M. 13 D., with posterior staphyloma and\\nchoroidal changes right, Em. left eye.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0379.jp2"}, "380": {"fulltext": "362 THE REFRACTION OF THE EYE\\nIn this case, in the good eye, there was a corneal astig-\\nmatism of 1.50 D., which was neutralized by a like amount of\\nastigmatism within the eyeball, perhaps by a lenticular astig-\\nmatism of that amount. Be that as it may, the simple spheri-\\ncal glasses are perfectly satisfactory, a -f 1.25 D. being ordered\\nfor each eye. Of course no attempt Avas made to fit the right,\\nthe glass being used for it merely to balance that in the left,\\nthe good eye.\\nCase CXXXVI. Congenital absence of the iris; Corneal\\nastigmatism with the rule^ 1.50 I), right and 2 D. left^ axis 5\u00c2\u00b0\\nand 175\u00c2\u00b0, respectively Total astigmatism 1. D. each^ witli the\\nsame axes as the corneal astigmatism; In eightee^i months time\\nthe corneal astigmatism did not change^ hut the total increased\\nto 2.50 D. in each eye^ axis 180\u00c2\u00b0 each^ due to slight luxation\\nupivard and tilting backward of the upper edges of the crystalline\\nlenses. I have already reported this case from which the\\naccount is now in the main taken. Annie M. B., aged six,\\nwas brought to me by her mother, April 12, 1897, to have\\nglasses fitted. The mother states that soon after the birth\\nof the child she noticed something peculiar about the eyes.\\nAs the patient grew up she avoided the bright lights and\\nalways squinted the eyelids when in the sunlight. The child\\nhas always enjoyed good health, and, except for the defect in\\nthe eyes, is sound. Since the birth of this, the first child, the\\nmother has been delivered of two other children, sound in\\nevery respect. Both the father and mother are health}^ and\\nwithout defect, and the mother says this is the first member of\\neither her or her husband s family thus afflicted. The father,\\nmother, and tAvo 5^ounger children are all slightly hyperme-\\ntropic, while the patient has compound mj -opic astigmatism.\\nExamination of the eyes. The ophthalmometer shows\\nastigmatism with the rule, 1.50 D., axis 95\u00c2\u00b0-}- or 5\u00c2\u00b0\u00e2\u0080\u0094 right\\n1 Post-Graduate^ November, 1898.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0380.jp2"}, "381": {"fulltext": "EXCEPTIONAL CASES 363\\n\u00c2\u00abye; 2. D. 85\u00c2\u00b0+ or 175\u00c2\u00b0- left eye. The ophthalmoscope\\nshows complete absence of the iris in each eye, nothing but\\na very narrow pigment-ring at the extreme periphery of the\\ncornea being present. Nothing of the ciliary processes can be\\nseen either with the ophthalmoscope or by oblique illumination.\\nThe lenses are clear and circular, except a slight nick in the\\nlower edge of the right. The vitreous is clear and the fundus\\nnormal in each. The fibres of the zonule of Zinn can be seen\\ndistinctly below and at the sides, but not so plainly above, as\\nthe lenses are slightly displaced upward. The diameter of\\nthe lenses can be seen with the ophthalmoscope to become\\ndistinctly smaller when the patient makes strong efforts at\\naccommodation.\\nR. y. 32JL 1^ w. 4.50 D. 1 D. cyl., 5\u00c2\u00b0.\\nL. V. 2V0 li W. 5 D. 1 D. cyl., 175\u00c2\u00b0.\\nReads Jaeger No. 2 at 8 inches with these glasses.\\nThe above glasses, ground in No. 2 London-smoke glass, to\\nkeep the excessive light from the eyes, were ordered, and with\\nthese the patient has pursued her studies at school with com-\\nfort for eighteen months. I may say that neither stenopseic\\nslit or puncture improved the vision. The tension of the eye\\nhas remained normal.\\nI presented the case before the New York Ophthalmological\\nSociety, October 10, 1898. The vision at that date was about\\nthe same as when the patient first came under observation. The\\ncorneal astigmatism remains exactly the same, but the total has\\nincreased considerably (1.50 D. in each eye} by reason of the\\nlenses being displaced a little upward and the upper margins\\nbeing tilted slightly backward. The myopia has increased to\\nsome extent. The patient now accepts 5 D. 2.50 D. cyl.,\\n180\u00c2\u00b0 right, and -6 D.- 2.50 D. cyl., 180\u00c2\u00b0 left. The lenses\\nremain clear, but with a suspicion of faint striie of opacity in", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0381.jp2"}, "382": {"fulltext": "364 THE REFRACTION OF THE EYE\\nthe lower halves. The luxation upward is not more than 1 to\\nIJ mm., and not enough to cause diplopia.\\nIn this case there is no question w^iatever of the increase of\\nthe total astigmatism being due to the slight luxation upward\\nand tilting backward of the upper edge of the crystalline lens.\\nThe displacement and tilting of the lens could be plainly seen\\nby reason of the absence of the iris. The ophthalmometer\\nshowed absolutely no increase in the corneal astigmatism.\\nThis case, together with others reported, proves beyond\\nquestion that lenticular astigmatism may be caused by an\\noblique position of the lens.\\n(2) Cases showing variation as to the axes of the corneal\\nastigmatism and total astigmatism.\\nCase CXXXYII. Corneal astigmatism with the rule^ axis\\n90\u00c2\u00b0+ or 180\u00c2\u00b0\u00e2\u0080\u0094 in each eye; Patient accepts minus eyli^idrical\\nglasses, axis 15\u00c2\u00b0 right eye, and 30\u00c2\u00b0 left eye. October 12, 1895,\\nMr. C. H. D., aged 28 years, in good health, has worn glasses\\nfor six or seven years, consults me now because of redness of\\nthe eyelids and pain in the eyes.\\nOphthalmometer. Astigmatism with the rule, .75 D., axis\\n90\u00c2\u00b0+ or 180\u00c2\u00b0- each eye.\\nTest cards and trial lenses.\\nV- 2 A |t W. 3 D. .50 D. cyl., 15\u00c2\u00b0.\\nL. V. ^Vo 1^ W. 3 D. .75 D. cyl., 30\u00c2\u00b0.\\nReads Jaeger No. 1 from 5 to 18 inches.\\nOphthalmoscope. M. 4 D. in each eye. No fundus lesion.\\nOn a second test the ophthalmometer gave the same reading\\nas at first however, the patient accepted the glasses as at first,\\nthat is, 15\u00c2\u00b0 and 30\u00c2\u00b0, respectively, distant from the axis as indi-\\ncated by the ophthalmometer. The glasses were satisfactory\\nas long as the patient was under observation, which was about\\nsix months.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0382.jp2"}, "383": {"fulltext": "EXCEPTIONAL CASES 365\\nCase CXXXVIII. Ophthalmometer shows corneal astig-\\nmatism with the rule^^ 60\u00c2\u00b0 or 150\u00c2\u00b0 left eye; Patient accepts a\\nplus cylinder axis 30\u00c2\u00b0, that is^ 30\u00c2\u00b0 distant from the point indi-\\ncated hy the instrument. Mrs. L. R., aged fifty years, has worn\\nglasses for the last eight years, but none of them have been\\ncomfortable, and she comes now to see if she cannot get better\\nglasses.\\nOphthalmometer. Astigmatism with the rule, 1 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 right eye 1 D., axis 60\u00c2\u00b0 or 150\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nR. Y. 1^ 1^ W. .75 D. .50 D. cyl., 90\u00c2\u00b0.\\nL. V. II- f-o- W. .75 D. .50 D. cyl., 30\u00c2\u00b0.\\nReads Jaeger No. 1 from 9 to 20 inches, with 2 D. sphere\\nadded.\\nOphthalmoscope. H. 1.50 D. each.\\nSecond test ophthalmometer gave exactly the same read-\\ning as at the first test.\\nR. V. 1^ 1^ W. 1.25 D. .50 D. cyl., 90\u00c2\u00b0.\\nL. V. f-^ 1^ W. 1.50 D. -f- .50 D. cyl., 30\u00c2\u00b0.\\nThis last glass was ordered for distant vision, and 2 D.\\nsphere was added to it for reading.\\n(3) Cases with discrepancies both as to the axis and the\\namount of the astigmatism.\\nCase CXXXIX. Corneal astigmatism ivith the ride in each\\neye; Total astigmatism is against the ride and at different axis\\nfrom that of the corneal astigmatism; Marked asthenopia; Re-\\nlieved hy the glasses accepted on subjective examination, which\\nglasses were not according to the reading of the ophthalmometer.\\nThis case was examined by Dr. Kinney in his private practice,\\nand it is through his courtesy that I am able to report it here.\\nNovember 22, 1897, Mrs. S. L. M., aged thirty-eight, consulted", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0383.jp2"}, "384": {"fulltext": "266 THE REFRACTION OF THE EYE\\nDr. Kinney, complaining of headaches and a strained feeling\\nin the eyes Avhen she used them to any extent. She is in fairly\\ngood health, but is troubled with malaria.\\nOphthalmometer. Astigmeitism. with the rule, .50 D., axis\\n75\u00c2\u00b0 or 165\u00c2\u00b0 right eye with the rule, .75 D., axis 105\u00c2\u00b0 or\\n15\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nR. V. 1^ -If W. .75 D. cyl., 165\u00c2\u00b0.\\nL. V. ff ff W. .50 D. cyl., 165\u00c2\u00b0.\\nReads Jaeger No. 1 from 10 to 20 inches with the distance\\nglasses.\\nOphthalmoscope. Showed hypermetropia of about 1 D. in\\neach eye. Normal fundi, and no opacities in the refractive\\nmedia that could be discovered.\\nSecond and third tests resulted in the patient accepting\\nexactly the same glasses as at the first one, and the glasses\\nwere prescribed. They have been worn with comfort for about\\neighteen months.\\nIn this case the astigmatism differed considerably in amount,\\n.75 D. in each after deducting .50 D. from the reading of the\\ninstrument for astigmatism with the rule. As to the axis, the\\njprincipal meridians of the cornea and lens (assuming lenticu-\\nlar astigmatism against the rule to be the cause of the discrep-\\nancy) coincided in the right ej^e, yet the axis of the cylinder\\nhad to be worn at right angles to that indicated by the instru-\\nment, because the total astigmatism was against the rule. In\\nthe left eye the principal meridians of the cornea and lens did\\nnot coincide, because the cylinder, though worn against the\\nrule, did not take the axis at right angles (at 15\u00c2\u00b0) to the astig-\\nmatism indicated by the ophthalmometer with the rule, but at\\na position 30\u00c2\u00b0 distant from that meridian, that is, at 165\u00c2\u00b0.\\nYery likely, as has been proved by actual measurements in", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0384.jp2"}, "385": {"fulltext": "EXCEPTIONAL CASES 367\\nsome cases by Donders, this meridian represented a mean\\nbetween the principal meridian of the cornea and lens.\\nCase CXL. Corneal astigmatism with the rule^ .50 D.; Pa-\\ntient accepts .50 D, cylindrical glass against the rule in each\\neye. November 20, 1897, Emily S., aged thirty years, has\\nworn glasses for three years, came to the clinic of Drs. Lewis\\nand Van Fleet, at the Manhattan Eye and Ear Hospital, to\\nl^e fitted with glasses. On examination I found the following\\nconditions\\nOphthalmometer. Astigmatism with the rule, .50 D., axis\\n105\u00c2\u00b0 -h or 15\u00c2\u00b0 right eye with the rule, .50 D., axis 75\u00c2\u00b0 or\\n165\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nR. Y. 10 _ 11 _|_ w. .50 D. cyl., 15\u00c2\u00b0.\\nL. V. If f f W. 4- .50 D. cyl., 165\u00c2\u00b0.\\nReads Jaeger No. 1 from 5|- to 15 inches.\\nOphthalmoscope. H. 1 D. in each eye.\\nThe patient accepted exactly the same glasses on a second\\ntest, though the ophthalmometer still showed corneal astigma-\\ntism, .50 D., with the rule. A plus .50 D. cyl., 15\u00c2\u00b0 right, and\\nplus .50 D. cyl., 165\u00c2\u00b0 left, were ordered. They proved entirely\\ncomfortable.\\nHere the corneal astigmatism and the internal astigmatism\\nhad their principal meridians coinciding, but the lenticular\\nastigmatism (assuming the internal astigmatism to be in the\\nlens) exceeded the corneal astigmatism in amount by .50 D.,\\nhence reversed the nature of the astigmatism in the total amount,\\nand required the cylinders to be worn with their axes exactly\\nat right angles to the axes indicated by the ophthalmometer.\\nCase CXLI. Large amount of corneal astigmatism against\\nthe ride^ ivith some irregular astigmatism Patient accepted cross\\ncylinders not at right angles to each other, the axis of the )ninus", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0385.jp2"}, "386": {"fulltext": "368 THE REFRACTIOX OF THE EYE\\ncylinder being worn 30\u00c2\u00b0 and that of the plus cylinder 45\u00c2\u00b0 removed\\nfrom the point indicated by the ophthalmometer Vision markedly\\nimproved luith the glasses^ and binocular single vision restored,\\nNovember 19, 1895, Mrs. Jacob H., aged thirty-seven years,\\nin good health, but is of a nervous temperament, consulted\\nme on account of a dacryocystitis and for glasses. After the\\ndacryocystitis was cured I fitted her with glasses. Previously\\nto my fitting her she had worn correction for one eye only, the\\nright.\\nOphthalmometer. Astigmatism with the rule, 1 D., axis\\n90^ or 180\u00c2\u00b0 right eye astigmatism against the rule, 8 D.,\\naxis 30\u00c2\u00b0 or 120\u00c2\u00b0 with irregular astigmatism, left eye.\\nTest cards and trial lenses.\\nL- V. 2V0 U 4-50 D. cyl., 90\u00c2\u00b0.\\nReads Jaeger No. 1 from 5 to 16 inches.\\nOphthalmoscope. R. 1 D. right eye, H. 1.50 D. at 90\u00c2\u00b0\\nand M. 5 D. at 180\u00c2\u00b0 left eye. The cornea (left) had some-\\nwhat the appearance of a conical cornea, and the shadows\\nresembled somewhat those so characteristic of conical cornea\\nyet, on a side view of the cornea, no particular bulging of that\\nmembrane could be detected. The radii of curvature by the\\nophthalmometer in the principal meridians were but slightly\\nshorter than those of the average cornea. There were no\\nopacities of the media in either eye, and the fundus in each\\nwas normal.\\nSecond test the ophthalmometer gave exactly the same\\nreading as at first.\\nR. V. f^ 1^ W. 4- .75 D. cyl., 90\u00c2\u00b0.\\nL. V. 2V0 f^ ^-50 D. cyl., 90\u00c2\u00b0 2 D. cyl., 165\u00c2\u00b0.\\nAd. 12\u00c2\u00b0, ab. 6\u00c2\u00b0, sur. R. and L. 2\u00c2\u00b0. Single binocular vision\\nis present, both for the distance and the near point.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0386.jp2"}, "387": {"fulltext": "EXCEPTIONAL CASES 369\\nA third test corresponded with the second, and the glasses\\nwere ordered: +.75 D. cyl., 90\u00c2\u00b0 right, -4.50 D. cyl.,\\n90\u00c2\u00b0 2 D. cyl., 165\u00c2\u00b0 left.\\nI have kept this patient under observation for more than\\ntwo years, and within a few months I have seen her husband,\\nwho tells me the glasses are still satisfactory and the patient\\ncomfortable.\\nPerhaps the irregular astigmatism present in this case is\\nenough to account for the discrepancy between the reading\\nof the instrument and the glasses accepted on the subjective\\nexamination.\\nCase CXLII. Corneal astigmatism with the rule; Patient\\naccepts cylindrical glasses against the rule. November 27, 1897,\\nMiss M. S. came to the clinic at the Manhattan Eye and Ear\\nHospital, because of a marked asthenopia and blepharitis margi-\\nnalis. She was examined by Dr. Kinney, and by his courtesy I\\nwas allowed to see the case and report the same here.\\nOphthalmometer. Astigmatism with the rule, .75 D., axis\\n75\u00c2\u00b0 4- or 165\u00c2\u00b0- right eye .75 D., axis 105\u00c2\u00b0 or 15\u00c2\u00b0- left eye.\\nTest cards and trial lenses.\\n1^ if W. .50 D. cyl., 15\u00c2\u00b0.\\nL- It ff W- -2^ cyl., 105\u00c2\u00b0.\\nReads Jaeger No. 1 from 5 to 20 inches.\\nA second test corresponded in every particular with the\\nfirst, most careful examination being made because of the dis-\\ncrepancy between the reading of the instrument and the astig-\\nmatism found by the subjective examination in the right eye.\\nThe glasses were ordered as accepted, and they gave comfort\\nand relief from the asthenopia and blepharitis.\\nCase CXLIII. Corneal astigmatism against the rule Total\\nastigmatism against the rule, but with the a.ris of the cglinder 15\\nfrom the point indicated hy the instrument, right eye No corneal\\nastigmatism^ but total astigmatism o/1.25 i left eye. December", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0387.jp2"}, "388": {"fulltext": "370 THE REFRACTIOX OF THE EYE\\n24, 1895, Dr. L. W. H., aged fifty years, in good health, gives a\\nhistory of diplopia affecting the left eye alone (monocular)\\nfor the last two months. This diplopia is not constant, dis-\\nappearing and then recurring for a few days. On the first\\nappearance of the trouble in the left eye he had a mild con-\\njunctivitis, but that is about well. No history of syphilis,\\nrheumatism, or traumatism. On testing the muscles no insuffi-\\nciencies were found.\\nOphthalmometer. Astigmatism against the rule, .25 D.,\\naxis 165\u00c2\u00b0+ or 75\u00c2\u00b0\u00e2\u0080\u0094 right eye; no corneal astigmatism left\\neye.\\nTest cards and trial lenses.\\nR. V. ff f W. .50 D. .25 D. cyl., 180\u00c2\u00b0.\\nL. y. f^ f^ W. 1.25 D. cyl., 30\u00c2\u00b0.\\nReads Jaeger No. 1 from 8 to 24 inches, with 2 D. sphere\\nadded for presbyopia.\\nQjMhalmoscope. \u00e2\u0080\u0094YL. .50 D. right eye; H. 1 D. at 120\u00c2\u00b0\\nand Em. at 30\u00c2\u00b0 left eye. No opacities could be detected in\\neither lens, although in the left eye there seemed to be a\\nwavering or shimmering of the light in looking at the fundus.\\nThat there was not much the matter with the refractive media\\nis shown by the remarkable acute vision of the patient. One\\nwould naturally suspect a beginning cataract, to account for\\nthe occasional monocular diplopia, especially at his age, fifty\\n3^ears. As the doctor was from a neighboring state I have not\\nbeen permitted to follow up the case. Roosa^ claims that\\nfunctional diplopia is often seen in hypermetropia and hyper-\\nmetropic astigmatism, that it is not constant, and that it is\\nalways relieved by a correction of the error of refraction. (See\\nfull explanation on page 354.)\\nI prescribed the reading glasses for the patient, which were\\nsatisfactory at the time given.\\niRoosa, Defective Eyesight^ The Macmillan Co., N.Y.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0388.jp2"}, "389": {"fulltext": "EXCEPTIONAL CASES 371\\nCase CXLIY. No corneal astigmatism right eye Corneal\\nastigmatism against the rule 180\u00c2\u00b0 or 90\u00c2\u00b0 left eye^ hut the\\npatient accepts a plus cylinder at 150\u00c2\u00b0 instead of 180\u00c2\u00b0 as indi-\\ncated hy the ophthalmometer; Spasm of accommodation Mydri-\\natic used. November 8, 1898, Mr. G. D., aged eighteen,\\nstudent, consulted me on account of redness and pain in the\\neyes. The patient is in good health, but is a close student,\\nand his eyes hurt him most in the evening. On account of\\nthe conjunctivitis, I gave him an astringent wash and applied\\nalum to the lids once a day for a few days before giving him a\\ncareful test for glasses.\\nOphthalmometer. No corneal astigmatism right eye as-\\ntigmatism against the rule, .25 D., axis 180\u00c2\u00b0 or 90\u00c2\u00b0 left\\neye.\\nTest cards and trial lenses.\\nR. V. 1^ |o W. .25 D. -h .25 D. cyl., 180\u00c2\u00b0.\\nL. V. 1^ W. .50 D. cyl., 170\u00c2\u00b0.\\nReads Jaeger No. 1 from 4 to 18 inches.\\nOphthalmoscope. H. 1 D. each eye.\\nOn a second test the ophthalmometer gave the same read-\\ning as at first, but the patient would not accept the axis of the\\ncylinder as indicated by the instrument (left eye), but at 170\u00c2\u00b0\\nas on the first test. On this account, and because of the symp-\\ntoms of spasm of accommodation, I advised a mydriatic, but\\nthe patient declined, saying he was willing to make a trial\\nof the glasses without a mydriatic being used. I therefore\\nordered them. The glasses gave him comfort for about two\\nmonths, so that he could pursue his studies, but at the end of\\nthat time he returned, complaining of headaches and pains in\\nthe eyes. At this time he consented to have a mydriatic used,\\nand I paralyzed the accommodation with scopolamine, per\\ncent, solution, instilled one drop, every five minutes, six con-\\nsecutive times.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0389.jp2"}, "390": {"fulltext": "372 THE REFRACTION OF THE EYE\\nOphthalmometer. Astigmatism negative right eye astig-\\nmatism against the rule, .25 D. 180\u00c2\u00b0 or 90\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nR. V. 10 w. 1 D. .25 D. cyl., 180\u00c2\u00b0.\\nL. V. 32_(L 1^ w. 1 D. .25 D. cyl., 150\u00c2\u00b0.\\nOphthalmoscope. H. 1 D. each.\\nThree days later the patient accepted .75 D. .25 D.\\ncyl., 180\u00c2\u00b0 right, and .75 D. .25 D. cyl., 150\u00c2\u00b0 left, which\\nwere ordered. These glasses have given him entire com-\\nfort since, though he has used his eyes for long periods at\\na time.\\nThe cylinder accepted in the left eye had its axis at 150\u00c2\u00b0,\\nor 30\u00c2\u00b0 distant from the point indicated by the ophthalmometer,\\nafter a mydriatic was used.\\nCase CXLV. Lenticonus anterior; Corneal astigmatism\\nwith the rule., 2 D. in each eye Total astigmatism is against the\\nrule^ 5.50 D. in rights and 4 D. in the left eye Vision greatly\\nimproved with glasses. December 2, 1895, Mr. J. L. H., aged\\nfifty-seven, in good health, a lawyer, consulted me because of a\\nsevere migraine in the right side of his head, and pain in the\\nright eye. Four days previously he had migraine in the right\\nside of his head so severely that he was confined to his bed all of\\none day, and has been incapacitated for work ever since. The\\npain seems to radiate from the right side of his head to the\\nright eye. He has had such attacks before, but not so badly.\\nThere is no redness of the eye, nor is there any plus tension,\\nor any indication of glaucoma whatever. He has worn glasses\\nfor fifteen years for reading, with which he got fairly good\\nvision. He has never seen very well for distance or near.\\nHe is now wearing for reading the cross-cylinders 2.50 D.\\ncyl., 180\u00c2\u00b0 -3D. cyl., 90\u00c2\u00b0 right eye, and -f 2.50 D. cyl., 180\u00c2\u00b0\\n1.50 D. cyl., 90\u00c2\u00b0 left eye.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0390.jp2"}, "391": {"fulltext": "EXCEPTIONAL CASES\\n373\\nOphthalmometer. Astigmatism with the rule, 2 D., axis\\n90\u00c2\u00b0 or 180\u00c2\u00b0 right eye with the rule, 2 D., axis 75\u00c2\u00b0 or\\n165\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\n2%% tVo W. 2.50 D. 2.50 D. cyl., 90\u00c2\u00b0.\\nL. V. 2^0= U W. 1.50 D. 2.50 D. cyl., 75\u00c2\u00b0.\\nReads Jaeger No. 1 from 7 to 12 inches, with +1 D.,\\n2.50 D. cyl., 90\u00c2\u00b0 right, and -f- 2 D. 2.50 D. cyl., 75\u00c2\u00b0 left.\\nBecause of the great discrepancy between the astigmatism,\\nas indicated by the instrument, and that found on subjective\\nexamination, I immediately suspected some trouble with the\\nlens, an incipient cataract perhaps. On examination with the\\nophthalmoscope I found no opacity of the lens whatever, but\\nto my surprise a transparent protuberance of a conical shape\\non the front surface of the lens of each eye, somewhat like\\nthat represented in the accompanying diagram. The cornese\\nwere perfectly clear, except for a very\\nminute opacity just to the outer side of\\nthe center of the left. The shadows re-\\nflected from the pupil resembled in a\\nmarked degree the shadow-crescents seen\\nin conical cornea. I could not get a\\ndouble image of the fundus by the direct\\nmethod with the ophthalmoscope, as did\\nWebster in his case, the first of this kind\\nreported however, I did not have the\\npupil dilated as he did, and besides, the\\nconicity was not so marked in my case as\\nin his, so far as I can judge by reading\\nthe account of his case and looking at the excellent diagrams\\nhe gave.i With the indirect method, however, 1 got a\\nFig. 104. Diagram of\\nthe crj ^stalliue lens,\\nenlarged, giving a\\nside view. The front\\nof the lens with pvo-\\ntnberance on it is to\\nthe left.\\n1 Archives Ophtlial. and Otol, Bd. Vol. IV, 1874-1875, p. 382.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0391.jp2"}, "392": {"fulltext": "374\\nTHE REFRACTIOI^ OF THE EYE\\ndecided diplopia of the retinal blood-vessels, both vertical\\nand horizontal also the parallactic movement by which the\\ndouble images could be made to approach toward, or recede\\nfrom, each other by the slightest movement of the ophthalmo-\\nscope or object lens. The fundus was normal in each eye.\\nOn a second test the ophthalmometer gave exactly the same\\nreading as at first.\\nTest cards and trial lenses.\\n2V0 H W. 5 D. 2.50 D. cyl., 90\u00c2\u00b0.\\nW. 1 D. 3 D. cyl., 75\u00c2\u00b0.\\nT^ V 20 20\\n2 ST\\nReads Jaeger No. 1, 9 to 15 inches, with 1 D. 2.50 D.\\ncyl., 90\u00c2\u00b0 right, 3 D. cyl., 165 left eye. These reading\\nglasses were prescribed, and have been worn for more than\\nthree years with comfort however, his daughter tells me\\nthat in the last few months he does not get along so well with\\nthem as at first.\\nThis patient, according to the glasses which he was wear-\\ning when he came to me, had a total astigmatism in the right\\neye, 5.50 D., and in the left eye total astigmatism, 4 D., in\\neach against the rule. The ophthalmometer, however, gave\\nhim astigmatism in each eye, 2 D., with the rule. Hence, the\\nlens must have had an astigmatism of 7.50 D. in the right,\\nand 6 D. in the left, against the rule in each, in order to have\\nthe total astigmatism amount to 5.50 D. right and 4 D. left,,\\nagainst the rule. According to my own tests when he came to\\nme, he must have had a lenticular astigmatism against the\\nrule of 4.50 D. right and 5 D. left, in order to have a total\\nastigmatism against the rule of 2.5 D. right and 3 D. left,\\nbecause he had 2 D. of corneal astigmatism with the rule in\\neach eye.\\nThe following five cases are given, not because of the dis-\\ncrepancy in the astigmatism as measured by the ophthalmometer", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0392.jp2"}, "393": {"fulltext": "EXCEPTIONAL CASES 375\\nand that as found on subjective examination, but because they\\nare exceptional as regards the general run of cases in refractive\\nwork.\\nCase CXLYI. Corneal astigmatism with the rule .2-5 D.;\\nOn subjective examination the patient accepted plus .25 D. cylin-\\ndrical glasses against the rule; In four years time the axis of\\nthe corneal astigmatism and the axis of the total astigmatism^ as\\nbrought out by subjective examination^ had changed 30\u00c2\u00b0. Feb-\\nruary 8, 1894, H. D. R., aged thirty-one, in good health, is a\\ncivil engineer, and uses his eyes very hard in drawing, con-\\nsulted me because of pains in the eyes and an occasional\\nheadache. He had a well-marked conjunctivitis, for which I\\nprescribed an astringent wash, and treated a few days before\\ntesting for glasses.\\nOphthalmometer. Astigmatism with the rule, .25 D., axis\\n75\u00c2\u00b0 or 165\u00c2\u00b0 right eye .25 D. axis 105\u00c2\u00b0 or 15\u00c2\u00b0 left eye.\\nTe\u00c2\u00a7t cards and trial lenses.\\nR. V. f^ f^ W. .25 D. cyl., 165\u00c2\u00b0.\\nL. y. 10. _ 1^ VV. -h .25 D. cyl., 15\u00c2\u00b0.\\nReads Jaeger No. 1 from 4 to 24 inches.\\nOphthalmoscope. H. .50 D. each.\\nA second test ten days later resulted in the patient accept-\\ning exactly the same glasses as at the first test, and they were\\nordered for his close work.\\nThese glasses gave him relief from asthenopia, and he con-\\ntinued to use them for almost five years. For the last year of\\nthis time his old sjaiiptoms, eye ache and headache, came back\\nonce in a while.\\nDecember 9, 1898, I saw him again.\\nOphthalmometer. Astigmatism against the rule, .25 D.,\\naxis 135\u00c2\u00b0 or 45\u00c2\u00b0 right eye with the rule, .25 D., axis 45\u00c2\u00b0\\nor 135\u00c2\u00b0 left eye.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0393.jp2"}, "394": {"fulltext": "376 THE REFRACTIOX OF THE EYE\\nTest cards and trial lenses.\\nR. V. =1^ fl W. 4- .25 D. cyl., 135\u00c2\u00b0.\\nL. V. 1^ fl W. .25 D. cyl., 45\u00c2\u00b0.\\nReads Jaeger Xo. 1 from 6 to 20 inches.\\nOpJithahnoscojje. H. .50 D. each.\\nFour days later a second test, objective and subjective, cor-\\nresponded exactly with the previous test, and the glasses were\\nordered. He has worn them for four months with entire relief\\nfrom his asthenopic symptoms.\\nIn this case, both the corneal and total astigmatism changed\\naxes and in the same direction, and to the extent of 30\u00c2\u00b0.\\nCase CXLVII. Corneal astigmatism with the ride., with\\nthe principal meridians not at right angles. April 30, 1897,\\nMiss N. S., aged twenty-five, in good health, has worn glasses\\noff and on for the last ten years, but none of the glasses have\\ngiven her relief from a very troublesome asthenopia. She was\\nfitted with glasses twice under the influence of a mydriatic.\\nOphthalmometer. Astigmatism with the rule, 1 D., the\\nimages lining at 165\u00c2\u00b0 in first position, and at 60\u00c2\u00b0 in second\\nposition, right eye .75 D., the images lining at 15\u00c2\u00b0 in the first\\nposition, and at 120\u00c2\u00b0 in second position, left eye.\\nTest cards and trial lenses.\\nI^- M f^ W. 1.75 D. .50 D. cyl., 60\u00c2\u00b0.\\nL. V. f^ 1^ W. 1.25 D. .50 D. cyl., 120\u00c2\u00b0.\\nReads Jaeger Xo. 1 from 6 to 20 inches.\\nOjjhthalmoscope. H. 2.50 D. right eye, H. 2 D. left eye;\\nnormal fundi, no opacities in the cornese or lenses.\\nA second and third test resulted in the patient accepting\\nthe same glasses exactly as at the first test. The ophthalmom-\\neter gave the same reading in the three tests. The glasses\\nwere ordered, and gave immediate and continued relief from\\ni", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0394.jp2"}, "395": {"fulltext": "EXCEPTIONAL CASES 377\\nthe asthenopia. I saw the patient in March, 1899 (two years\\nafter), v/hen she informed me that she had used her eyes\\nconstantly as an artist, and that the glasses were still entirely\\nsatisfactory.\\nCase CXLVIII. Corneal astigmatism with the prificipal\\nmeridians not at right angles in the right eye^ hut at right angles\\nin the left eye. Mrs. J. E. M., aged fifty-eight years, in good\\nhealth, consulted me because her eyes, after using them for\\nclose work, got a sore feeling in them and became red,\\nespecially the right one. She has worn glasses for a number\\nof years; the last pair, 2.25 D. spheres, she has worn for eight\\nyears.\\nOphthalmometer. Astigmatism with the rule, 1. D., the\\nimages lining at 180\u00c2\u00b0 in first position, and at 75\u00c2\u00b0 in the second\\nposition, right qjq .50 D., axis 90\u00c2\u00b0 or 180\u00c2\u00b0 left eye.\\nTest cards and trial lenses.\\nR. y. 1^ I J W. .50 D. cyl., 180\u00c2\u00b0.\\nL. V. 1^ not improved with any glass.\\nReads Jaeger No. 1 from 8 to 16 inches, with plus 3 D.\\nsphere added.\\nOphthalmoscope. Em. in each eye apparently. There is\\nno opacity of the lenses or the cornese, and fundi are normal.\\nThe reading glasses were ordered, 2.50 D. -f .50 D. cyl.,\\n90\u00c2\u00b0 right, and 3 D. sphere left. These glasses relieved the\\nasthenopia, and she no longer complained of the sore and\\nstrained feeling in the right eye.\\nBoth in this case and in the one immediately preceding it,\\nthe cylinders accepted were not at right angles to the meridian\\nat error. For instance, in the right eye, in Case CXLYII, the\\ncylinder was accepted with its axis at 60\u00c2\u00b0, while the least\\ncurved meridian was at 165\u00c2\u00b0, as shown by the images lining\\nat that point, and, to be worn at right angles, its axis should\\nhave been at 75\u00c2\u00b0 while in the left eye the plus cylinder was", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0395.jp2"}, "396": {"fulltext": "378 THE REFRACTION OF THE EYE\\naccepted at 120\u00c2\u00b0, but the least curved meridian, which it was\\ngiven to correct, Avas at 15\u00c2\u00b0.\\nAnd so in tlie present case, in the right eye, the most\\ncurved meridian was found at 75\u00c2\u00b0, that being the second posi-\\ntion and the images overlapping nevertheless, the patient\\naccepted a minus cylinder, axis 180\u00c2\u00b0, while it should have\\nbeen worn at 165\u00c2\u00b0, to be at right angles to 75\u00c2\u00b0,\\nI may say, however, that in some cases, where the principal\\nmeridians are not at right angles, I have seen the patient\\naccept the cylinders with their axes exactly at right angles to\\nthe meridians at error. So it is well in such cases to try the\\ncylinders at both the positions indicated by the ophthalmome-\\nter, and 15\u00c2\u00b0, or at any number of degrees of inclination the\\nchief meridians have toward each other from that of a right\\nangle.\\nCase CXLIX. Large amount of astigmatism^ the corneal\\nand total corresponding closely as to amount and exactly as to\\naxis Patient accepts the glasses as indicated hy the ophthalmome-\\nter with marked improvement in vision^ hut cannot wear any cylin-\\ndrical correction^ preferring simple spheres. March 27, 1893,\\nMiss K. N., aged thirty-seven years, in good health, came to\\nme for glasses. She has worn spherical glasses for close work,\\nbut not for distance, for ten years. None of them have ever\\nbeen entirely comfortable to the eyes. She complains now of\\noccasional headache and pains in the eyes, especially in the\\nafternoon and evening.\\nOphthalmometer. Astigmatism with the rule, 1.25 D., axis\\n120\u00c2\u00b0 or 30\u00c2\u00b0 right eye; 5.50 D., axis 80\u00c2\u00b0 or 170\u00c2\u00b0 left\\neye.\\nTest cards and trial lenses.\\nR- M -I^W. .T5 D. cyL, 120\u00c2\u00b0.\\nL. V. 2V0 H W. 4.50 D. cyl., 80\u00c2\u00b0.\\nReads Jaeger No. 1 from 8 to 15 inches.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0396.jp2"}, "397": {"fulltext": "EXCEPTIONAL CASES 379\\nOphthalmoscope.\u00e2\u0080\u0094 Y.m. at 120\u00c2\u00b0 and H. 1 D. at 30\u00c2\u00b0 right\\n\u00e2\u0082\u00acye; Em. at 75\u00c2\u00b0 and H. 5 D. at 165\u00c2\u00b0 left. No opacities of\\nthe cornea or lens in either eye, and no abnormal condition of\\nthe fundus could be detected in either eye. No muscle insuffi-\\nciency.\\nA second test was given, and as the patient accepted the\\nsame glasses as at first, they were ordered.\\nThe patient tried faithfully to wear them for two months,\\nbut claimed they did not help her in the least, in fact, that\\nthey made the vision worse, because they elongated objects\\nvery much in the horizontal meridian. A simple +2 D.\\nsphere in each eye gave her more comfort than any other\\nglasses, and these she continued to wear till her death four\\nyears later.\\nIn this case, as well as the one to follow, little or no dis-\\ncrepancy in the axis and in the amount of the astigmatism, as\\nmeasured by the ophthalmometer and that found on subjective\\nexamination, existed, nevertheless, the patients were not able\\nto wear any cylindrical correction whatever. In seeking an\\nexplanation of the behavior of the eyes in these two cases, and\\nin the others like them, which cases, I may say, are found in\\nlater life, in presbyopes, as a rule, who have never worn any\\ncorrection in early life, or only a spherical one, though highly\\nastigmatic, I can do no better than quote the words of Bonders\\non the action of cylinders in general in the correction of astig-\\nmatism, and then make a deduction from them in reference to\\nthe cases here under consideration. He says\\nThe correction of regular astigmatism by means of cylindrical glasses\\nis incapable of absolute perfection. Apart from the amblyopia, which, inde-\\npendently of the light-refracting system, complicates many cases of astig-\\nmatism, the acuteness of vision must, even with the most accurate correction,\\nleave something to be desired, because the asymmetry of the astigmatic eye\\n-cannot be completely counteracted by the presence of a cylindrical lens.\\nMoreover, the correction is only of that nature that the posterior focal\\npoints for tlie different meridians are brought together without the same", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0397.jp2"}, "398": {"fulltext": "380 THE REFRACTION OF THE EYE\\nbeing true of the other cardinal points. The absolute coincidence of the\\nnodal points in the different meridians is scarcely attainable. If they lie in\\nthe principal meridian of slightest curvature more posteriorly, correction\\nwith a biconvex cylindrical lens brings them more forward than those in\\nthe meridian of greatest cm^vature and vice versa if they be situated more\\nanteriorly, on correction by a biconcave cylindrical lens, they are moved\\nmore backward. In this is implied that the form of the bodies, on correc-\\ntion of astigmatism, is elongated in a direction opposite to that in which,\\nbefore correction, elongation existed, etc.^\\nIn other words, in cases of high degrees of astigmatism,\\nwhich have gone without correction till late in life, the subjects\\nhave become accustomed to images of objects much elongated in\\na certain direction, and when we come to correct the astigmatism\\nin these cases we greatly elongate the images in exactly the\\nother direction, or the elongation is in the direction at right\\nangles to what it was before correction. This is so disturbing\\nand so upsetting to all previous ideas of the form and size of\\nobjects, that some patients simply will not have it, even though\\nthe vision, so far as test-types are concerned, is greatly im-\\nproved by them, as witness the two cases here reported.\\nFurthermore, the axes of the astigmatism in both of my cases\\nwere oblique (and against the rule in one case), and this of\\nitself made it much more difficult for them to get used to the\\ncylinders in fact, they could not, or would not, wear the cylin-\\ndrical correction.\\nCase CL. Corneal astigmatism against the rule, with oblique\\nor slanting axis Total astigmatism exactly the same as to axis\\nand almost identical as to amount; Patient^ vision is greatly\\nimproved with cylindrical correction, yet he cannot wear it.\\nApril 2, 1897, Mr. G. H. W., aged sixty-eight years, in very\\ngood health considering his years, consulted me for reading\\nglasses. He has never worn glasses for the distance, but has\\nworn simple spherical glasses for near vision since he was\\n1 Loc. cit; p. 509.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0398.jp2"}, "399": {"fulltext": "EXCEPTIONAL CASES 381\\nforty-five years old, with which he has gotten along fairly well,\\nthough his vision has always been rather poor.\\nOphthalmometer. Astigmatism against the rule, 2.50 D.,\\naxis 5\u00c2\u00b0 -I- or 95\u00c2\u00b0 right eye against the rule, .50 D., axis\\n170\u00c2\u00b0 or 80\u00c2\u00b0 left eye.\\nTest cards and trial lenses,\\nI^. V. 2\u00c2\u00a5o l\u00c2\u00ab W. 2.50 D. cyl., 5^\\nL. V. iVo M W. 1.50 D. .75 D. cyl., 170\u00c2\u00b0.\\nReads Jaeger No. 1 from 9 to 20 inches, with 4 D. sphere\\nadded.\\nOphthalmoscope. ^H. 2 D. at 90\u00c2\u00b0 and Em. at 180\u00c2\u00b0 right\\neye H. 2 D. at 90\u00c2\u00b0 and H. 1 D. at 180\u00c2\u00b0 left; normal fundi;\\nno opacities of the refractive media.\\nThe reading glasses were prescribed, and the patient made\\npersistent efforts to use them for six weeks, but finally gave\\nthem up because of the great disturbance caused by the elon-\\ngation of images in the vertical meridian. With simple\\nspherical glasses he got tolerably clear vision for the read-\\ning distance, print appearing natural, if not so distinct as with\\nthe cylindrical correction and he much preferred and was more\\nsatisfied with the spherical correction.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0399.jp2"}, "400": {"fulltext": "I", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0400.jp2"}, "401": {"fulltext": "APPENDIX\\nIMPROVEMENTS ON THE JAVAL-SCHIOTZ OPHTHALMOMETER\\n(a) DAVIS S DOUBLE-MOVABLE MIRES (5) VALK S GEAR-\\nWHEEL ATTACHMENT; (c) SKEEL S PERPENDICULAR LEVER\\nADJUSTMENT; (d) METAL BASE AND OTHER MINOR IM-\\nPROVEMENTS. REID S OPHTHALMOMETER, A DESCRIPTION\\nOE IT AND HOW TO USE THE INSTRUMENT. OTHER OPH-\\nthalmometers\\nDavis s Double-movable Mires for Javal-Schiotz s\\nOphthalmometer\\nBy the term ^double-movable mires I mean that both mires, or\\nTeflectors (the graduated and rectangular), move at the same time\\nand to an equal extent, and not one (graduated), as in the old\\ninstrument, while the other (rectangular) remains fixed 20\u00c2\u00b0 from\\nthe center of the arc. The advantage of having both mires move\\ninstead of one is that in so doing both mires are kept the same\\ndistance from the center of the arc, and their images the same\\ndistance from any point on the cornea that is being measured;\\nwhereas, as the old instruments are constructed, one mire (rectan-\\ngular) remains fixed at 20\u00c2\u00b0 from the center of the arc on one side,\\nwhile the graduated mire on the other side is required to do\\nall the moving. This is very well if the point on the cornea hap-\\npens to be of just sufficient radius of curvature in the meridian\\nbeing measured to allow the image of the movable graduated mire\\nto just touch the image of the rectangular mire when the graduated\\nmire reaches the twenty-degree mark on its respective side of the\\narc. The mires would then be at an equal distance from the center\\nof the arc, and their images, consequently, at equal distances from\\nthe point on the cornea measured. If, however, the meridian\\nof the cornea under measurement is of such radius of curvature\\n1 Reprinted from the New York Medical Journal, Eebruaiy 10, ISOo.\\n383*", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0401.jp2"}, "402": {"fulltext": "384 THE REFRACTION^ OF THE EYE\\nas to allow tlie graduated mire to come closer than. 20\u00c2\u00b0 on its\\nrespective side of the arc before the images of the mires touch, its\\nimage must necessarily be formed on the surface of the cornea\\nnearer the point measured. On the other hand, if the meridian\\nunder measurement is of such radius of curvature that the images\\nof the two mires approximate before the graduated mire reaches the\\ntwenty-degree mark on its side of the arc, then its image will, of\\ncourse, be formed on the surface of the cornea at a greater distance\\nfrom the point measured than the image from the rectangular mire,\\nwhich is fixed at 20\u00c2\u00b0 on the opposite side of the arc. I think\\nmy point is clear. ISTow, since the human cornea (its apex, or\\npoint on it where the visual line intersects its surface) is very\\nrarely of just the radius of curvature to allow the graduated mire to\\ncome exactly to 20\u00c2\u00b0 on its respective side, the same distance as\\nthe fixed mire on the opposite side, in order to have the images\\ntouch, any improvement that keeps both mires at the same distance\\nfrom the center of the arc in every case, whatsoever the curvature\\nof the cornea may be, is a decided advantage. The double-movable\\nmires accomplish this perfectly.\\nThose who are only fairly well acquainted with the use of the\\nophthalmometer are aware of the fact that not the whole of the\\ncornea is measured in an ordinary ophthalmometric examination,\\nbut only a very small portion of it a space only of 2^ to 3 mm.\\nin diameter. Furthermore, the center of this space does not\\ncoincide with the center of the cornea, except when the visual\\nline coincides with the long axis of the cornea,^ but with that\\npoint on the cornea intersected by the visual line, which point is\\nusually a little to the nasal side of the center of the cornea, and,\\nas a rule, on a horizontal line with it. Or, again, this point may lie\\nto the temporal side of the corneal center. The space included\\nbetween this visual line and the optic axis, forward from the point\\nwhere they cross, is the well-known angle alpha, which is positive,\\nnil, or negative, accordingly as the visual line lies to the nasal side\\nof, coincides with, or is toward the temporal side of the optic axis.\\nWhen the angle alpha is nil or very small, as it is in the majority of\\ncases, the center of the small space measured on the cornea practi-\\ncally coincides with the center of the cornea, and the measurements\\nof the ophthalmometer in such cases, with the proper restrictions, as\\n1 Practically the same as the optic axis.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0402.jp2"}, "403": {"fulltext": "APPENDIX 385\\nlaid down by Javal, agree usually with the glasses accepted by the\\npatient. When, however, this angle is large, especially when there\\nis a large amount of astigmatism associated with a high degree of\\nhypermetropia or myopia, the readings of the ophthalmometer do\\nnot correspond so closely with the subjective test. For example, in\\nthe natural eye, with a radius of curvature of 8 mm., an angle alpha\\nof 6\u00c2\u00b0 is 0.9 mm., or, practically, 1 mm. and, with an angle alpha\\nof 12\u00c2\u00b0, it would, of course, be 2 mm. In such a case, therefore,\\nthe point on the cornea measured by the ophthalmometer would be\\n2 mm. distant from the center of the cornea to the nasal or temporal\\nside, accordingly as the angle is positive or negative. Now, the two\\nchief radii of curvature at this point may be considerably different\\nfrom the radii of curvature at the apex, either one or both of\\nthem. To simplify matters, we will assume that in a given case the\\nradius of curvature changes in but one of the chief meridians,\\nthat of the vertical, while it remains unchanged in the horizontal.\\nLet the radius of curvature of the horizontal meridian at the apex\\nbe 8 mm., and that of the vertical meridian 7.61 mm. According to\\nJaval s formula, D 1000 the astigmatism at the apex in\\nr\\nsuch a case is 2 D. Say, however, at 2 mm. distant from the apex\\nthe radius of the vertical meridian changes from 7.61 mm. to\\n7.31 mm., while the radius of curvature of the horizontal meridian\\nremains the same as at the apex. According to the same formula,\\nD 1000 the astigmatism at this point would be 4 D. The\\nr\\ndifference in the amount of astigmatism at the two points would\\nclearly be 2 D. Of course, this is a much exaggerated case, but it\\nserves to illustrate how a large angle alpha may affect the readings\\nof the ophthalmometer, and how the astigmatism at the apex of the\\ncornea may vary from that at the point on the cornea intersected by\\nthe visual line. This error holds against the double-movable mires\\nas well as the single-movable mire, but not to the same extent, and for\\nthis reason Besides having the radii of curvature of the two chief\\nmeridians differ, which difference represents the amount of astigma-\\ntism present, the radius of curvature may be different in one and\\nthe same meridian and not necessaril}^ have marked irregular astig-\\nmatism, as in low degrees of conical cornea, or even where there is\\nno conical cornea, it being a well-known fact that the farther we go", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0403.jp2"}, "404": {"fulltext": "386 THE REFRACTIOX OF THE EYE\\ntoward the periphery of the cornea the flatter its surface becomes.\\nThis slight change^ of radius of curvature in the same meridian\\nmay be present in one or both of the two chief meridians of curva-\\nture. Moreover, the difference in the radius of curvature in the\\nsame meridian is likely to be greater the farther away the second-\\nary point of measurement is made from the primarj Herein, in\\nfact, lies the advantage of double-movable mires over the single-\\nmovable mire. With double-movable mires, both images remain the\\nsame distance from the point on the cornea under measurement, and\\nrelatively closer to it than in the single-movable mire. Por, as has-\\nalready been pointed out above, in the instrument with the single-\\nmovable mire, one mire must remain fixed at 20\u00c2\u00b0 from the center of\\nthe arc, while the other may be nearer to or farther away, accord-\\ningly as the radius of curvature happens to be longer or shorter than\\n8.38 mm., the radius of curvature of the cornea (and the only one, by\\nthe way), which, by Javal s old instrument, allows the movable mire-\\nto be exactly the same distance from the center of the arc (20\u00c2\u00b0) as\\nthe fixed mire is, and the images touch. If shorter than 8.38 mm.,\\nboth images will become smaller, and to a relative extent, if the\\ncurve is constant and the movable mire would have to be displaced\\nfarther than 20\u00c2\u00b0 on the arc in order to have the images just approx-\\nimate. If the surface of the cornea, from which this image of this\\nrelatively too far displaced movable mire is reflected, happens to\\nhave a radius of curvature (in one and the same meridian) slightly\\nshorter than that point on the cornea from which the image of the\\nfixed mire is reflected, then the image from the movable mire would\\nbe actually smaller than that from the fixed mire. Again, if the\\nradius of curvature happens to be longer than 8.38 mm., both images\\nwill be larger, and the movable mire would have to be moved closer\\nthan 20\u00c2\u00b0 in order to have the images touch. Consequently, the\\nimage from the fixed mire, in this instance, if the surface from\\nwhich it is reflected is shorter in radius of curvature than that from\\nwhich the image of the movable mire is reflected, will be actually\\nsmaller than that from the movable mire. Conversely to both of\\nthe above cited cases, and as most often happens, when the radius\\n1 When it is remembered that exactness to the fraction of one one-hun-\\ndredth of a millimeter in measuring the radius of curvature of the cornea is\\ndemanded, the importance of noticing even slight changes of curvature in the\\nsame meridian will he apparent.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0404.jp2"}, "405": {"fulltext": "APPENDIX 387\\nof curvature of the surface of the cornea, from which the image of\\nthe relatively too far displaced mire is reflected, is longer than that\\nfrom which the image of the relatively too close mire is reflected,\\nthe amount of astigmatism, as measured by the single-movable mire,\\nis greater than when measured by the double-movable mires. Fur-\\nthermore, other things being equal, the farther removed this image\\nof the relatively too far displaced mire is from the center under\\nmeasurement, the greater the change in the surface of the cornea is\\nlikely to be, with, of course, a resultant increase in the error. With\\ndouble-movable mires, this error does not obtain to the same extent\\nas with the single; hence the advantage of the former over the\\nlatter. However, if there was no advantage in this respect, it is a\\nplainly desirable thing to have both mires move and be kept at an\\nequal distance from the center of the arc, and their images equidis-\\ntant from the center on the cornea under measurement.\\nIn a year s experience with the double-movable mires I have\\nfound, in astigmatism of a comparatively small amount from one\\nto four diopters, with little or no hyperopia or myopia, and the angle\\nalpha nil or very small that the readings differed but little from\\nthose of the single-movable mire, the readings with the double-mov-\\nable mires most of the time being less than with the single-movable\\nmire, about .25 D. to .50 D. less. On the other hand, in astigmatism\\nof large amount, especially when associated with a high degree of\\nhyperopia or myopia, where the angle alpha is usually large,^ the\\nreadings have differed more, often as much as .50 D., and sometimes\\nas much as 1 D., the double mires usually giving the less amount.\\nFurthermore, the subjective tests corresponds closer with the read-\\nings of the double mires than with those of the single-movable\\nmire.^\\nIn irregular astigmatism the readings with the double-movable\\nmires proved much more satisfactory than the readings with the\\nsingle-movable mire.\\nThe modus operandi of the double-movable mires consists in a\\nthumb-screw attached to the arc on the same side as the graduated\\nor movable mire, about two inches from the telescope. On the\\nattached end of this screw are cogs, into which other cogs on slender\\n1 The angle alpha in these cases was measured with caudle and perimeter.\\n2 I have used the double-movable mires for five years uo^Y, aud am more\\nfavorably impressed with them than ever.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0405.jp2"}, "406": {"fulltext": "388\\nTHE REFRACTION OF THE EYE\\nshafts extend to each mire play (Fig. 105, A). Thus, by a simple\\nturn of the screw, both mires are moved at the same time to an equal\\nextent, in or out, and at pleasure. In this way both mires are kept\\nthe same distance from the center of the arc in every case.\\nHaving both mires move at one time necessitates the regradua-\\ntion of the arc, both for radius of curvature and for diopters.-^ The\\nregraduation for the radius of curvature is obtained by the formula\\n7? 7? D T\\nI D: ^i which reduced is, R In this formula\\n^^M} mwww\\nB\\nFig. 105.\\nIt represents the radius of curvature to be found; 0, the object^\\nwhich in Javal s instrument is the imaginary line between the inner\\nedges of the reflectors or mires 7, the size of the corneal image,\\nwhich is constant, and equals 2.95 mm. D, the distance of the\\nobject from the cornea, also a constant quantity, 560 mm. being\\ndouble the focal distance of the objective, Avhich in Javal s instru-\\nment is 280 mm.^\\n1 So far as the diopter marks on the posterior border of tlie arc are con-\\ncerned, perhaps it would be as well, or better even, not to regraduate for them,\\nbut to leave them as they are. Because, by leaving them as they now are, the\\nnumber of diopters corresponding to any radius of curvature is easily obtained\\nby simply doubling the number of diopters indicated by the graduated mire.\\n2 This is the focal distance given by Dr. Sulzer also 2.95 mm. is the size of\\nthe corneal image given by this writer in his description of Javal s instrument\\n{Description de V ophtalmometre Javal et Schiotz, modele 1889, par le Docteur\\nSulzer, de Winterthur).", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0406.jp2"}, "407": {"fulltext": "APPENDIX\\n389\\nTo obtain the radius of curvature to be marked in millimeters on\\nthe inner edge of the arc, corresponding with the 20 D. mark on\\nthe posterior edge of the arc, we have\\nR\\n2 X 280 X 2.95\\n8.38 mm.,\\n200 295\\nand so on, as low down as 6 and as high up as 46, respectively, on\\neach side of the 20 D. mark, the radius of curvature ranging from\\n13 mm. for the 6 D. mark to 5 mm. for the 46 D. mark (105, B). This\\ndoubles the width of range of the instrument with the single-mov-\\nable mire, and is of service in conical cornea or in very high degrees\\nof astigmatism often present after cataract extraction.\\nTo regraduate the posterior edge of the arc for the new diopter\\nmarks it is only necessary to begin at the 20 D. mark as it now\\nstands, and, going each way, divide the diopter spaces into halves,\\ngiving to each half the same value that the whole space now repre-\\nsents, and number them accordingly. For example, where 21 now\\nis, 22 should be placed where 22 is, 24, and so on and on the other\\nside of the 20 D. mark, where 19 now is, 18 should be written, and\\nwhere 18 is, 16, and so on (see Fig. 105, B).\\nValk s Gear-wheel Attachment\\nConsists simply of a small cogwheel attached to the side of the\\ntelescope back of the large disk, with the cogs in this small wheel\\nFig. 106.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0407.jp2"}, "408": {"fulltext": "390\\nTHE REFRACTION OF THE EYE\\nmade to fit into cogs whicli have been placed around the telescope\\n(Fig. 106). By this arrangement the telescope can be revolved evenly\\nand the arc and pointers moved for very small distances and main-\\ntained at any position given them.\\nSkeel s Perpexdicular Lever Adjustment\\nBy means of a lever placed in the posterior foot of the the tripod,\\nthe upright, together with the whole instrument, can be raised or\\nlowered in a perpendicular direction. This is certainly an improve-\\nment to the tilting backward and forward movement given to the\\nFig. 107.\\ninstrument when the simple screw alone is used, as in the old\\ninstrument (Fig. 107).\\nOther minor improvements on the chin-rest, forehead-rest, rack\\nand pinion for the mires, shade, curtains to keep light from the eyes\\nof the observer, etc., have been made. The adjustable forehead-\\nrest made by Fox and Stendicke, of this city, is of practical\\nadvantage.\\nDrs. Giles and Chapman have made some modifications in the\\ninstrument so as to make it portable, that is, to be carried in a con-\\nvenient case. See description of same in Medical Record, July 25,\\n1896.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0408.jp2"}, "409": {"fulltext": "APPENDIX 391\\nDr. W. S. Dennett, of New York, has made an improvement on\\ntlie electric light attachment.^\\nMeyrowitz s solid metal base for the instrument to rest on is\\nmuch preferable to the old wooden base or planchette of the\\nimported instrument.\\nAccurate measurements without any of the above improvements,\\nhowever, can be made with the 1889 model, simply by taking a little\\nmore time and care. Those who do not care to go to the expense of\\nadding all of the improvements to an already expensive instrument\\ncan procure the unimproved instrument at a moderate cost.\\nMeyrowitz has made a new model of the Javal-Schiotz ophthal-\\nmometer. In this model he has left off the large dial of Placido,\\nand replaced it with a smaller black dial. At the same time he has\\nadded a smaller dial at the back of the telescope, by which the axis\\nof the astigmatism is read off.\\nThe advantages claimed for this model are (1) That the tripod\\nsupporting the instrument is permanently attached to the base,\\nthereby giving it greater steadiness, and is moved forward and back-\\nward by a rack and pinion, while the lateral motion is given by a\\nrevolving joint at the foot of the tripod; (2) The improvements\\nmade on the 1889 model of the Javal instrument are retained.\\nAmong these are the perpendicular adjustment of the entire\\ninstrument (Skeel s), and the simultaneous movement or double-\\nmovable mires (Davis s). A new and important improvement to\\nthis latter movement has been made by the addition of a beveled\\ngear attachment which permits the manipulation of the mires from\\nthe back of the large dial and by means of a circular scale with\\ndouble automatic pointers corresponding to the graduations on the\\narc, the relative position of the mires on the arc can be read with\\ngreat accuracy.\\nAnother new feature is the raising and lowering of the chin-rest\\nfrom the opposite end of the ophthalmometer, by means of a cam\\noperated by a long rod and milled head at the end of same, so that\\nthe operator need not change his position. Below a good cut of the\\ninstrument is given.\\nAnother new model of the ophthalmometer is that made by\\nChambers and Inkeep, of Chicago. The special advantages that\\n1 iYeto York Eye and Ear Inrirmarn Feports, 1804. II. 27.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0409.jp2"}, "410": {"fulltext": "892\\nTHE REFRACTION OF THE EYE\\nthey claim are: (1) Stationary luminous mires; (2) Adjustable\\nprisms.\\nThere are still other models of the instrument on the market,\\nbut, in my opinion, the 1889 model of Javal and Schiotz is as accu-\\nrate as any of them. Not only that, but measurements outside of\\nFig. 108.\\nthe visual line can be made with the 1889 model, because it has the\\nlarge dial of Placido attached, while all of the new model instru-\\nments have replaced it with a plane black disk or dial.\\nArtificial Corner\\nSome eight or nine years since, Javal made an artificial cornea,\\nastigmatic in nature, which could be attached to the chin-rest of the\\ninstrument, and used for testing the correctness of the ophthal-", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0410.jp2"}, "411": {"fulltext": "APPENDIX\\n393\\nFig. 109. Javal s Artificial\\nCornea.\\nmometer itself. Since the radii of curvature of the principal\\nmeridians of this artificial cornea are known, and their exact re-\\nfractive power in the equivalent diopters, it is easy to tell if an\\ninstrument is at fault in its measurements.\\nThe meridian of shortest radius of cur-\\nvature represents a refractive power of\\n44.2 D., while the meridian of longest ra-\\ndius represents a refractive power of 42.5 D.\\nThe difference between these two numbers\\ngives the amount of astigmatism of the\\nartificial cornea, 1.7 D., which of course\\nis constant. The axis of this astigmatism,\\nhowever, can be changed at will, since the\\ncornea is on a movable disk. The merid-\\nian of shortest radius of curvature is indi-\\ncated by an arrow. Consequently when the arrow points to 0\u00c2\u00b0\\n(directly above on the rim), the astigmatism is with the rule and\\nwhen pointed horizontally to 90\u00c2\u00b0, the astigmatism is against the\\nrule. All intermediate positions, of course, can be taken. Because\\nof the brilliant images which it gives, and the fact that it can be\\nlooked at for a long while, make it of much practical value to the\\nbeginner, because he can prac-\\ntice on it.\\nMorgan s artificial cornea\\nhas been constructed to be used\\nin connection with the Javal\\nophthalmometer. It consists of\\na highly polished glass hemi-\\nsphere, ground to the radius of\\na normal cornea, and placed in\\nthe center of a graduated cell,\\nsimilar to such as are found on\\ntrial frames. When attached\\nto the head-piece of the oph-\\nthalmometer, the cornea occu-\\npies the position intended for\\nthe eye of the patient. In this way the ophthalmometer can readily\\nbe tested, and adjusted if necessary. For purposes of denu^nstva-\\ntion, this normal cornea can, b}^ the insertion of a cylindrical lens\\nFig. 110. Morsran s Artificial Cornea.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0411.jp2"}, "412": {"fulltext": "394\\nTHE REFRACTION OF THE EYE\\ninto the revolving cell, be converted into an astigmatic cornea of\\nany desired degree, with the axis at any given angle.\\nReid s Ophthalmometer\\nThe inventor s original description of his instrument is as fol-\\nlows The object of the instrument about to be described is to\\nmeasure the curvature of the central area of the cornea, the polar\\nor optical zone; or of any spherical reflecting surface from 6 to\\n10 mm. radius. In its present form the instrument can only be\\napplied to the measurement of the corneal surface in the visual line.\\nAs this is the area of the cornea utilized for distinct vision, this\\ninstrument furnishes all the data practically requisite for the diag-\\nnosis and measurement of corneal astigmatism.\\nThe theory of its construction is based on a particular appli-\\ncation of the following well-known optical law: That when two\\ncentered optical systems are so combined that their principal foci\\ncoincide, the ratio of the size of the object to the size of the image\\nformed by the combined systems is equal to the ratio of the princi-\\npal foci of the two optical systems, adjacent respectively to object\\nand image. The two optical systems in this case are the convex\\nlens of the instrument and the cornea as a reflecting surface, with\\nthe object in the principal focus of the adjoining optical system.\\nThus {vide Fig. 1)\\nLet MM^ be the convex lens of known surface, A the corneal\\nsurface, and P the point where the principal foci coincide.\\nLet SPhe an object situated at the principal focal distance of\\nMM and let XX be the principal axis of the system.\\nThen a ray SM parallel to the axis will, after refraction, be\\n1 From the Annals of Ophthalmology and Otology, April, 1896.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0412.jp2"}, "413": {"fulltext": "APPENDIX 395\\ndirected to the principal focus P of the curved surface of the cornea,\\nand therefore be reflected in the direction IB parallel to the axis\\nXX\\\\ IB prolonged will meet the ray directed to the center C at\\nthe point S therefore, S^ is the image of S, and S P is the image\\nof SP, and S^F^ is in the principal focus of the convex reflecting\\nsurface.\\nIn the similar triangles MP O and IP A,\\nP O^MO\\nP A lA\\nSM and IS\\\\ the prolongation of the reflected ray, are parallel to the\\naxis XX therefore SP MO and S P lA.\\nrri. f P O SP OF\\nTherefore or\\nP A SF I f\\ntherefore (1)\\nI r\\n2FxI\\n^^Description of the Instrument\\nThe essential parts of the instrument are an aplanatic convex\\nlens of known focus, a rectangular prism neutralized in its center by\\na smaller prism, one side of the rectangular prism being adjacent to\\nthe lens, and a circular or other disk being opposite the other side in\\nthe principal focus of the lens. When the instrument is held in\\nfront of the convex reflecting surface with the disk turned toward a\\nluminous source, a virtual image of the disk will be formed at the\\nvirtual focus of the convex reflecting surface. This image will only\\nbe seen distinctly by the emmetropic eye through the neutralized\\nportion of the prism when the focus of the lens in front coincides\\nwith the virtual focus of the convex surface. The ratio of the\\nobject to the image will be as shown above. If noAv a double-image\\nprism be inserted behind the neutralizing prism, which exactly\\ndoubles this image, its power with the combination is easily deter-\\nmined, and therefore the exact size of the image can be measured.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0413.jp2"}, "414": {"fulltext": "396\\nTHE REFRACTION OF THE EYE\\nThe size of tlie object being known, we have the three elements\\nnecessary for determining the fourth proportional, the curvature of\\nthe convex reflecting surface.\\n^^The instrument in this simple form presented a number of\\npractical difficulties in its manipulation, which were overcome by the\\nintroduction of a short telescope behind, with double-image prism\\nfixed in front of its object-glass.\\n^^In its present form the instrument consists of the following\\nparts (vide Fig. 2^) An aplanatic lens Ob, a rectangular prism P\\nneutralized in the visual axis by a smaller prism P^, and a telescope,\\nwith the double-image prism BP fixed in front of the object-glass of\\nthe telescope OjBI The focal length of the object-glass OB^ is pre-\\ncisely the same as that of the aplanatic lens Ob, and cross-wires CW\\nat its principal focus are viewed by a Ramsden eye-piece.\\nBefore using the instrument it is necessary and sufficient that\\nthe cross-wires should be distinctly seen at the punctum remotum of\\nthe observer. The adjusted instrument is held in the observer s\\nleft hand, which rests on the forehead of the patient, the disk being\\ndirected to a luminous source to the right of the observer. The point\\nof coincidence of the principal foci is found by moving the instru-\\nment to and fro. When the observed eye is directed to the central\\nor fixation point and his visual line is vertical to the point of the\\ncornea through which it passes, the corneal image doubled and in-\\nverted ought to be seen in the center of the field. Instead of using\\ncircular disks of different dimensions, the size of the image required\\nto produce exact contact in any meridian is conveniently and quickly\\nobtained by making the required change in the size of a carefully\\ncoiistructed iris diaphragm. By using a circular object the circular,", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0414.jp2"}, "415": {"fulltext": "APPENDIX 397\\nelliptical, or irregular form of the image reveals at once the con-\\ndition of the surface. When the image is elliptical the meridian of\\ngreatest curvature is easily found by rotation of the telescope, and a\\nrotation of 180\u00c2\u00b0 gives a controlling observation. By a similar pro-\\ncess the meridian of least curvature is determined.\\nGraduation of the Instrument\\nLet D be the power in diopters of the cornea as a refracting\\nsurface, with a medium behind it of uniform density having an\\nindex of refraction n 1.337 approximately.\\njy^ (n- 1)1000\\nr\\n^337\\nr\\nCombining equation (1) with (11),\\n337 X O\\n(11)\\nD\\nD-\\\\-l\\n21F\\n337 X 0\\n2IF\\n1 (0 0).\\n2IF^\\nIn the present instrument 1=2, and 2F= 52,\\ntherefore 7= 3.24 (0 0),\\n-^=0 -0:\\n3.24\\ntherefore ID rather less than i mm.\\nThe index is divided into two parts, outer and inner. The\\nouter registers the size of the image, and the inner the correspond-\\ning diopters.\\nThe degree of refinement with which the measurements may\\nbe carried out depends entirely on the degree of exactness of deter-\\nmination of the constants, especially and F. I has been determined\\nexactly to inch, and can be estimated to about y^Vo\\nfocal length of the object-glass can be determined by Cornu s\\nmethod, but in general it is more convenient to measure two-curved", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0415.jp2"}, "416": {"fulltext": "398 THE REFRACTION OF THE EYE\\nsurfaces whose radii are exactly known, and within the limits of the\\ninstrument.\\nThe index error is found by taking the number of diopters at\\nsufficiently great intervals within the limits of the instrument. In.\\nthis instrument, if we take the extremes of the index, 12 mm.\\nand 16 mm., we find the corresponding diopters are 38.9 D. and\\n51.84 D. The index being graduated in thirds of a millimeter, the\\nindex error of each division is nearly 0.08 D., which is positive.\\nIf the double prism be now removed, the image being sijigle,\\nand the pupillary opening generally distinctly visible, it affords a\\nmeans of determining whether the visual axis passes through the\\ncenter of the pupil.\\nIt will be seen that this instrument differs from the ophthal-\\nmometer of Helmholtz, the most perfect instrument theoretically\\nand practically which has been devised for this purpose, in which,\\nwhile the object is constant, the image varies with the curvature of\\nthe surface, but always covers the same angular interval of the\\nsurface. It resembles the ophtlialmometre pratique of Javal and\\nSchiotz, in which the doubling is effected by means of a double-\\nimage prism inserted between two achromatic lenses of equal focus,,\\nso that while the image is constant the object is made to vary.\\nWith this instrument, when the difference of curvature of the prin-\\ncipal meridians is considerable, amounting to 3 or 4 D., in order to\\nobtain approximately accurate results, it is necessary to insert bi-\\nrefractive prisms of different powers, giving images of from 1 to\\n3 mm. In the present instrument the image of 2 mm. has been\\nselected as giving sufficiently accurate results for the most practical\\npurposes, measuring with precision, as it does, a difference of refrac-\\ntion of half a diopter. For cases outside the limits referred to (6 to\\n10 mm.) prisms of suitable powers can be substituted.\\nThrough the courtesy of Messrs. J. H. G. W. Hahn, New\\nYork City, I had the use of a Reid s ophthalmometer in my office\\nfor about five months time, and I wish to express my thanks in this\\nplace to the Messrs. Hahn for their kindness in the matter.\\nIn that time I had many opportunities to compare it with the\\nJaval-Schiotz instrument in testing for astigmatism.\\nIn astigmatism of low and moderate amount, up to 4 D., I found\\nit as accurate as the Javal-Schiotz ophthalmometer, as to amount.\\nI must say, however, that it was not so accurate in placing the axis", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0416.jp2"}, "417": {"fulltext": "APPENDIX 399\\nof the astigmatism. Especially was this so in astigmatism against\\nthe rule. Dr. Murdock, of Baltimore, who is familiar with the\\ninstrument, praises the instrument highly, in fact, believes it more\\naccurate than the Javal-Schiotz instrument, though he found the\\nsame difficulty in iinding the exact axis in astigmatism against the\\nrule that I have spoken of. He says: Its weak point, in my\\nhands, but not in Dr. Eeid s, is the difficulty encountered in deter-\\nmining the exact angle of an axis against the rule. The two images\\nthat one looks, at are circles, and I find it difficult to tell when they\\nfirst separate or when they reach the furthest point of separation.\\nIn high amounts of astigmatism, as in conical cornea and after\\ncataract extraction, it was not equal to the Javal-Schiotz instrument\\nby any means in fact, in the very high amounts of astigmatism, it\\ncould not measure it even approximately.\\nIn comparison with the Javal-Schiotz instrument it suffers under\\nthe further disadvantage of not giving the radius of curvature of\\nthe cornea in millimeters, as does the former instrument. It is true\\nthat the radius can be calculated by a simple formula, but in office\\nwork we do not care to waste time in such calculations. There is\\nno question but that it is a handy instrument as a portable ophthal-\\nmometer, and is easy to use; but, as a rule, patients who want\\nglasses fitted are able to come to the office of the oculist. Besides,\\nin America at least, we have a portable Javal-Schiotz ophthalmome-\\nter (Drs. Giles and Chapman s). In conclusion, I may say, the\\ncost of the two instruments is about the same.\\nDr. C. A. Oliver, of Philadelphia, has invented an adjustable\\nbracket for the Eeid ophthalmometer,^ his description of which is\\nhere appended\\nAfter several years trial with the various forms of ophthal-\\nmometers (keratometers) and much experimentation with the Eeid\\ncontrivance (by far the best of them all), I have found that for office\\nuse I have been able to obtain much better results as regards both\\naxis and degree of corneal astigmatism by having the instrument\\nmounted upon an adjustable table, which, by the employment of\\nfour leveling screws and a circular form of spirit-level, can be kept\\nabsolutely level in all horizontal directions during the examination,\\n1 Annals of Ophthalmology and Otology^ April, 1806, p. 324.\\n2 Read before the December, 1898, meeting of the Section on Ophthalmok gy\\nof the College of Physicians of Philadelphia.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0417.jp2"}, "418": {"fulltext": "400 THE REFRACTION OF THE EYE\\nthus insuring a greater degree of certainty of answer in reference to\\naxis than when the instrument was held in the hand.\\nThe apparatus practically consists of a rigid, vertical, steel rod\\nholding a sliding bracket, upon which there is fixed a combined\\nleveling table containing the instrument.\\nThe ophthalmometer itself is held in position by two angular\\nsupports that are bolted to the upper table, and is so arranged that\\na mere pressure by the hand will release it from their grasp, thus\\nmaking it portable and allowing it to be used as originally intended.\\nRising from the circumference of the table there are two fixed\\nrods, holding on their upper tips a pair of horizontally placed\\nsleeves, through which can be slid a fixation bar that can be bolted\\ninto any position that may be desired by a few turns of two screw-\\nheads that pass through threaded openings in the upper parts of the\\nsleeves. The rod that is placed on the registering side of the instru-\\nment contains a large circular area, which is situated just opposite\\nto the position of the translucent dial.\\nSituated on the top of the table is a carefully constructed, broad,\\ncircular level composed of a metallic air-tight chamber, covered by\\nglass. In the center of the glass cover is an etched circle of one\\ncentimeter diameter. This chamber, with the exception of an area\\nwhich is of the same size as that of the etched circle on the glass\\ncover, is filled with alcohol, thus making a bubble of air which, if\\nthe table be level in every horizontal direction, w^ill be situated\\nimmediately beneath, and rendered exactly coincident with the\\netched glass area above. At the periphery of the table, between\\nthe circular spirit-level and the edge of the table, there are four\\nfenestrated, threaded heads passing through the entire thickness of\\nthe table itself.\\nBeneath the upper tilting or instrument and spirit-level holding\\ntable there is a leveling or fixed table fastened firmly to an upright\\nsupporting rod. Upon this table four immobile pointed heads are\\nsituated.\\nBetween the two tables, loosely supported on the four pointed\\ncones of the lower table, there are four grooved, broadly headed\\nleveling screws that pass through the fenestrations in the upper\\ntable, so that the slightest turn given to any one of them will cause\\nthe bubble of air in the spirit-level to change its position.\\nIn the latest model of instrumentation (not shown in the sketch)", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0418.jp2"}, "419": {"fulltext": "APPENDIX\\n401\\nthere is a central spiral spring firmly held in an upright position\\nbetween the two tables, by which means the upper table is kept\\nsecurely fixed in whatever position the leveling screws ma}^ have\\nplaced it.\\nTo the ophthalmometer itself there\\nhas been added (which cannot be seen\\nin the sketch) a scale by which the exact\\naxis of the meridia of the greatest and\\nthe least corneal refraction can be im-\\nmediately read off.\\nIf desired, the instrument and the\\nleveling tables may be supported on\\nan optometer or phorometer bracket or\\ntripod, or they can be screwed to the\\ntop of a table or clamped to the back\\nof a chair, thus making them very light\\nand easily transportable.\\nTo use the instrument, the verti-\\ncal rod is bolted to a window-frame in\\nsuch a way that by a mere turn of the\\nbracket either eye may be studied (or\\nif so desired the window curtain can be\\ndrawn and either a source of artificial illumination substituted for\\nthe daylight, or, as the author prefers, a small adjustable aperture\\nin the opaque shade may be opened and the diffuse daylight allowed\\nto fall directly upon the disk).\\nThe patient being placed in position, and the ophthalmometer\\nproperly adjusted, the work is proceeded with in the ordinary way.\\nAdjustable bracket for the Reid\\nophthalmometer.\\nHardy s Ophthalmometer^\\nThe first ophthalmometer was designed by Helmholtz, in the\\nfirst half of the present century but the principle involved therein\\nwas not reduced to practical utility until 1884, when Doctors Javal\\nand Schiotz^ in Paris, designed the present model. The principle\\non which it is based is the 7neasurevient of corneal curves by means of\\nreflected images viewed through a telescope.\\nUniversity Medical Magazine, July, 1899.\\n2 Descriptiou taken from Hardy s catalogue.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0419.jp2"}, "420": {"fulltext": "402\\nTHE REFRACTIOX OF THE EYE\\nImages reflected, from curved surfaces vrill vary in size accord-\\ning to the radius of curvature of those surfaces, when the objects\\nreflected therefrom are uniform in size and distance. For in-\\nstance, a circle 20 cm. in diameter, placed at 28 cm. distance,\\nwould produce a larger reflected image on a cornea which has\\na long radius of curvature than would be produced on one with a\\n-N\\nFig. I.\\nshorter radius. So that, if it were possible to measure the size of\\nthe images of the above object reflected from a cornea, the exact\\nradius of curvature of that cornea could be calculated. Or, con-\\nversely, if an image of a given size, say 3 mm., is reflected from the\\ncornea, the curvature of the latter can be calculated from the size of\\nthe object required to produce 3 mm. at 28 cm. distance. It is evi-\\ndent, therefore, that the problem to be solved in constructing an", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0420.jp2"}, "421": {"fulltext": "APPENDIX\\n403\\nophthalmometer has been how to either measure the size of the\\nimage reflected from the cornea, or to obtain on the cornea an image\\nof a fixed size, say 3 mm. in diameter.\\nThe device employed accomplished both of these results, and is\\nshown in section in Fig. I.\\nIt consists of a telescope T, to which are attached arcs car-\\nrying sliding targets A and B, called mires. The telescope\\nhas a combination of lenses such that a surface, when viewed\\nthrough it, will be exactly in focus when the mires A and ^B^\\nare at 2S cm. distance therefrom. By this means the first element\\nis obtained, namely, a fixed distance between the cornea and the\\nobject to be reflected from it.\\nBetween the two objectives of the telescope there is placed a\\nbi-refringent prism ^P. This is a prism which has the property\\nof doubling in one plane objects seen through it. For instance, a\\ncircle viewed through the telescope containing the prism will appear\\ndoubled. The prism is so adjusted that when the telescope is in\\nfocus the distance between any two corresponding points of the\\ndoubled images will be ex-\\nactly 3 mm. consequently,\\nwhen a cornea is viewed\\nthrough this instrument, it\\nis seen doubled, the reflec-\\ntion of the mires from the\\ncornea also being doubled,\\nand the distance between\\neither edge of the two im-\\nages of one of the mires\\nwould be exactl}; 3 mm. In\\nF ig. II is shown an enlarged\\nview of the cornea, with the\\nmires reflected on it, as seen\\nthrough the telescope.\\nNow, if the distance be-\\ntween the right-hand edge of\\nthe primary image of the stepped mire A, and the right-hand edge\\nof its secondary image A is exactly 3 mm., and if the right-\\nhand edge of the secondary image A i^ exactly in contact with the\\nleft-hand edge of the primary image B, of the other mire, it is at\\nFig. II.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0421.jp2"}, "422": {"fulltext": "4 j4\\nTHE KEFRACTIOX OF THE EYE\\nonce CTident that the distance between tlie inner edges of the two\\nmires on the arcs is equal to the size of the object which will give\\non the cornea a reflected image 3 mTn. in diameter. Consequently,\\nwe have here all the means of calculati::i ureied to give as riie\\nradial? cf curvature of the Qpmeal surface.\\nTIt mires are made movable on the arcs, one of them having a\\nzi-i z _: :n cE. Fig- I i:r ^r -zient, so that the Of er-\\n~_:^t zinr fhroTigli zhe teles::^e. c:.ii slide the mires away\\nr: 11 :z r i. c Tier. Tintil their two central images on the cor-\\n7- arcs are graduated on their inner edges\\n1 r _l ~ji^ iTi:i:rive power in diopters and quarters of a\\npiano lens having rhe same curve as the corneal curve indicated by\\nthe position of the mires. A scale is also provided on the other\\nedge of the arc. giving the zadins of the cornea. But, as the instm-\\nniriir is i-ifzj isri ior diagnc^ing astigziarisni. ine lirst scale is\\nI\\nK\\nformed as sii:~n in E:g. TIT: one has a simple\\nTiier. with a sir 5 i strps. arranged in groups,\\nniv counted: c-jni having a black line bisecting\\nthenu and a black background.\\nOn the stepped mire, each\\nstep represents a diopter, the\\ndistance between the edge of\\nthe first step and the line of\\nthe edges of the small white\\nsquares represents a diopter,\\nand each of the small squares\\nand the black space between\\nthen, represent diopters.\\nThe ares carrying the mires\\nbeing farther away from the\\ncornea than the nires themselves, in other words, beiug on a circle\\nof longer radius than th n h: :h the mires move, the difference\\nin the radius is allowei ni h graduation of the arc.\\nThe mathematical principle ing the construction of the\\ninsrmment is, that a given distance c-etween the mires and the cor-\\nner :t 28 cm., and a separatLon of the images by the bi-refringent\\nn. i mm., then each 5 mm. of distance between the inner\\nc^g^; :i the two mires is equal to 1 D. in a medium having the\\nFig. HL\\nJ", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0422.jp2"}, "423": {"fulltext": "APFEXDIX 405\\nrefractive po^er of a hiunaii cornea. So that tlie size of the steps\\nof the mire must be exactly o mm., and the graduation on the arc\\nenough farther apart to compensate for its longer radius.\\nThe numberings of the graduations on the inner edge of the arc,\\ntherefore, are intended to show the number of half-centimeters dis-\\ntance betAveen the inner edges X and Y,* Fig. Ill of the white\\nspaces on the two mires. The two edges above mentioned are set\\non the slide carrying them, so that they are exactly in line with\\nthe inner edges of the slides. And the graduation on the arcs next\\nto the inner edges of the slides, added together, give the readings of\\nthe instrument. For instance, in Fig. I the inner edge of the mire\\nA stands at about 22^ on the arc, that of the mire B at 22^\\non its arc, making about 45 D. together and if the corneal reflec-\\ntions of the mires placed on the arcs as above have their inner\\nedges just in contact; as shown in Fig. V (not separated or over-\\nlapping, as shown in Figs. VI and VII resx^ectively), then the cur-\\nFiG. Y. Fig. Y1. Fig. Vn.\\nvature of the corneal surface indicated by the positions of the\\nslides on the arcs in that case would be such as to produce a focus\\nof 45 D.\\nThere is no such thing as a normal curvature for the human cor-\\nnea, but from statistics a radius of curvature of 7.829 mm. has been\\nsettled upon as that of the average cornea. Accordingly, we have\\nstamped on the arcs the letter ^A, to indicate the position of the\\nmires for a cornea of average curvature. A smaller distance between\\nthe slides than that shows a corneal curve of less than the average,\\nand, hence, a j^resHm/^tion of hypermetropia. A greater distance\\nindicated the reverse of the above, or r presumjytion of myopia.\\n\u00e2\u0080\u00a2\u00e2\u0080\u00a2The images of the two mires reflected from the cornea being\\nfarther apart on a cornea of k mger curvature, or nearer together on\\none of shorter curvature, it follows that, by moving the mires\\nuntil their images appear in contact (Fig. A the curve of the cor-\\nnea can be read off on the arc, as stated above, and the difference\\n1", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0423.jp2"}, "424": {"fulltext": "I\\n406 THE REFRACTIOX OF THE EYE\\nbetween the curvatures of the same cornea in different meridians\\ncan be determined in the same way.\\nBut the main object of the instrument is not to show the abso-\\nlute curvature of the cornea, but differences of curvature in its dif-\\nferent meridians, i.e. astigmatism. Hence, the stepped mire is\\nprovided, which indicates the amount of astigmatism existing by\\nthe overlapping or separation of the mires when rotated to the oppo-\\nsite meridian from that in which they were brought in contact.\\nThe angles of the two principal meridians are determined as fol-\\nlows The action of the bi-refringent prism is only in one direction,\\nand the line or plane of its action is exactly in the plane of the arc\\ncarrying the mires. By placing on the mires a black line H,\\nFig. Ill) also exactly in the plane with the arcs and the action of\\nthe prism, that line will only appear continuous through both\\nimages when it is reflected from one of the principal meridians.\\nWhen reflected from any other meridian, the\\nmires will appear as in Fig. YIII, with the\\nblack line broken.\\nThe telescope is mounted on a tripod, as\\nsho^vn in the cuts, and rests upon the stand\\ncontaining the chin-rest for the patient. It is\\nrotatable, allowing the arcs to be set at any\\nmeridian, their position, and also the meridian\\nFig. VIII. right angles to it, being shown by the index\\nfingers on the graduated disk.\\nThe whole instrument can be slid back and forth on the stand,\\nso as to focus it on the patient s cornea.\\nThe telescope, being provided with the correct combination of\\nlenses for that purpose, will show a clear image to an observer\\nhaving normal vision, when the mires are exactly 2S cm. distant\\nfrom the cornea.\\nAny error in the eye of the observer will affect the distance by\\nabout i mm. to each diopter of such error. That is to say, if the\\noculist using the instrument is myopic 2 D., it would focus with\\nthe mires at 281 mm. from the patient s cornea, in place of 280\\nmm. Hence, the readings of the instrument would be vitiated to an\\namount of about -g-i-g- of a diopter for each diopter of error in the\\neye of the oculist.\\nDoctors Javal and Schiotz corrected this by providing cross-", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0424.jp2"}, "425": {"fulltext": "APPENDIX 407\\nhairs in the tube holding the eye-pieces, so that by focussing it upon\\nthem the error in the oculist s eye could be compensated. But this\\nerror is so slight, and it is so utterly impossible to construct an\\ninstrument in which it would have any practical effect, that we\\nregard the cross-hairs as an unnecessary obstruction to the view,\\nand therefore omit them.\\nIn practical use, the main and most important feature of the\\ninstrument is its definition. For the object viewed through it is an\\nimage so small that each step on the stepped mire is less than of\\na mm. in diameter reflected from a surface that is often very dull.\\nSo that the lenses must be of very high grade, and their mounting\\nvery perfect, to prevent a lack of coincidence in their centering, in\\naddition to which the metal work must be rigid and closely fitted.\\nThe greatest difficulty met with in the manufacture of ophthal-\\nmometers has been that of obtaining perfectly clear quality of\\nquartz for the bi-refringent prisms. All the Paris-made instruments\\nhave this style of prism, with the result that many of them have\\nvery poor definition. We have, therefore, lately adopted the glass\\nbeveled slabs, as used in the Utrecht make, with the result of a\\nvery much better definition than elsewhere obtained.\\nDirections for Use\\nFrom the above description of the construction of the instru-\\nment, the following rules for its use will be easily understood\\nPlace the patient with chin on the rest, and forehead pressed\\nfirmly against the top of the head-rest, so as to keep the head per-\\nfectly steady. Cover one eye with the eye-cover, and tell the\\npatient to look into the end of the tube.\\nSet the two targets at A, on the graduated arcs, and revolve\\nthe instrument until the arcs are horizontal, and the index fingers\\npointing exactly to 90\u00c2\u00b0 and 180\u00c2\u00b0 respectively. Sight through the\\nslot in the large disk, and slide the instrument on the stand until\\nthe patient s eye is seen through the center of the slot, and is in\\nline with the telescope, the top of the cone being brought into line\\nwith the bottom of the cornea by turning the pinion in the base.\\n(A little practice with the individual instrument will enable its\\nowner to sight very accurately, so that on looking through the tele-\\nscope the images will be clearly in view.) Then slide the instru-", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0425.jp2"}, "426": {"fulltext": "I\\n408 THE REFRACTION OF THE EYE\\nment till the reflections of tlie images are sharply focussed. They\\nwill appear double, as is shown in Fig. VIII. The two outer\\nimages, B and A should be altogether disregarded, and the\\nattention fixed solely on the two central images, B and ^A.\\nThe instrument should be moved till the central images are exactly\\nin the middle of the field of view, as shown in Fig. Ill, and only\\nnow tell the patient to open the eye as much as possible, not only in\\norder to get a better image, but also to prevent pressure of the lids\\non the globe, which causes often a very considerable degree of astig-\\nmatism.\\nThe next step is to find the principal meridians, which is done\\nby revolving the instrument and noting separation of the two\\nimages. The meridian at which the two images appear nearest\\ntogether is the meridian of greatest refraction, and the meridian at\\nwhich they appear to be farthest separated is the one of the least\\nrefraction. The exact meridian is determined by finding the point\\nat which the horizontal line which bisects the two images is exactly\\ncontinuous, as is shown in Fig. V, instead of broken, as is shown in\\nFig. YIII. Having found one of the meridians exactly, move the\\ntarget along the arc by the rack and pinion till the edges of the\\nimages are just in contact; then rotate the instrument 90\u00c2\u00b0, and\\nthe amount of astigmatism can be determined by the amount of\\nseparation or overlapping of the images, as is shown in Figs. VI and\\nVII. The targets in Fig. VII overlap two steps, showing 2 D. of\\nastigmatism. Those in Fig. VI show a separation equal to two\\nsteps, as indicated by the square blocks in the margin of the targets,\\nso that in this figure an astigmatism of 2 D. is also represented.\\nConcise Rules\\nWhen measuring the amount of astigmatism by the overlapping\\nof the images\\n1. Focus and find center.\\n2. Find meridian of least refraction, viz., that on which the\\nimages appear farthest apart.\\n3. Approximate the images and find exact axis of the meridian.\\n4. Rotate 90\u00c2\u00b0.\\n5. Read off amount of astigmatism by overlapping of the\\nimages.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0426.jp2"}, "427": {"fulltext": "APPENDIX 409\\n6. Having proceeded according to this rule, the perforated index\\nfinger will indicate the axis of the greatest curvature, or that for a\\nplus cylinder, and the solid index finger ^A will indicate the axis\\nof least curvature, or that for a minus cylinder. (See Fig. XI.)\\nThe above is the method used with the French instrument, but\\nwe have added a new method for determining the amount of\\nastigmatism.\\nWe have attached to one of the racks a supplementary slide\\nS, Fig. I) with a set-screw. This slide is on the arc, outside of\\nthe slide carrying the target. After having found the meridian of\\ngreatest refraction, according to the above method, this supplemen-\\ntary slide should be brought against the slide carrying the target,\\nand should be fixed in position by the set-screw. This can easily be\\ndone without moving the eye from the telescope. Then rotate the\\ninstrument 90\u00c2\u00b0, when the image will appear to separate, and move\\nthe target by the rack and pinion till the edges of the two images\\nagain appear to exactly touch. Then note the angles of the two\\nprincipal meridians, as indicated by the index pointers, and the\\namount of astigmatism can be read off from the graduations on the\\narc. These graduations are made by one-quarter diopters.\\nThe supplementary slide being fastened in the first position,\\nand the slide carrying the target moved away from it to the second\\nposition, the number of graduations exposed between the two slides\\nrepresent the number of diopters and quarter diopters of astigmatism.\\nDistance Concise Rules\\nWhen using supplementary slide\\n1. Focus and find center.\\n2. Find the meridian of greatest refraction, which is that on\\nwhich the images appear nearest together.\\n3. Approximate the images and find exact axis.\\n4. Bring indicating slide against that carrying the target,\\nand fasten in position by the set-screw.\\n5. Eotate 90\u00c2\u00b0.\\n6. Approximate the images again.\\n7. Eead off amount of astigmatism on graduated arc.\\n8. Having proceeded according to the above rule, the solid index\\nfinger A (Fig. XI) will indicate axis of greatest curvature, or that", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0427.jp2"}, "428": {"fulltext": "410\\nTHE REFRACTION OF THE EYE\\nFig. XI.\\nfor plus cylinder, and perforated finger ^B will indicate axis of\\nleast curvature, or that for minus cylinder.\\nMy personal experience with the Hardy instrument extended\\nover a period of about two\\nmonths in my clinic at the\\nPost-Graduate School of Med-\\nicine. I found it a practical\\ninstrument and one of pre-\\ncision. In construction it\\nis very similar to Javal s in\\nits main features, and any\\none familiar with the use\\nof the Javal-Schiotz instru-\\nment can use the Hardy\\ninstrument.\\nWith other ophthalmometers, Kagenaar, etc., I have not had\\npersonal experience. Dr. George J. Bull s opinion of the Kagenaar\\ninstrument, whose judgment in such matters is of much value, is not\\nvery favorable, if we are to take his estimate of it as given in a\\nrecent article in the Ophthalmic Record, Vol. 7, p. 604, on The\\nUtility of the Ophthalmometer. He says Some have supposed\\nthat the rival ophthalmometer of Kagenaar or that of Hardy might\\nbe looked to with better results. Both ideas are entirely erroneous.\\nThe ophthalmometer of Kagenaar (and that of Hardy), although an\\ninstrument of considerable merit, has no real advantage as compared\\nwith the instrument of Javal, and it has the disadvantage that the\\namount of doubling produced by its prism varies with the distance\\nof the patient.\\nAll things considered, I myself prefer the Javal-Schiotz instru-\\nment to any other, and use it exclusively, except when making com-\\nparative tests.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0428.jp2"}, "429": {"fulltext": "INDEX OF CASES\\nCHAPTER III\\nSimple Hypermetropic Astigmatism Simple Hypermetropia\\nCase Page\\nI. Corneal astigmatism with the rule, 1 D., axis 90\u00c2\u00b0 or 180\u00c2\u00b0\\nPatient accepts .50 D. cyl., axis 90\u00c2\u00b0 45\\nII. Astigmatism with the rule, 4 D., axis 10\u00c2\u00b0, to the temporal side\\nof the vertical meridian in each eye Patient complains of no\\nasthenox^ia, but simply of poor vision Accepts 3.5 D. cyl. in\\neach eye 47\\nHI. Corneal astigmatism with the rule, .50 D., neutralized by lenticu-\\nlar astigmatism Patient accepts simple plus spherical glass 48\\nIV. Corneal astigmatism with the rule, .25 D., neutralized by the\\nlenticular astigmatism Patient accepts simple spherical glasses 49\\nV. Corneal astigmatism wdth the rule, .25 D., with no lenticular\\nastigmatism .50\\nVI. Corneal astigmatism with the rule, .50 D., with no lenticular\\nastigmatism 51\\nVII. Corneal astigmatism with the rule, 1 D. right eye and .75 D.\\nleft eye No lenticular astigmatism 52\\nVIII. Corneal astigmatism with the rule, 1 D., with no lenticular\\nastigmatism Presbyopia 52\\nIX. Hypermetropic astigmatism against the rule, 1 D. right eye,\\n.75 D. left eye Patient accepts .50 D. more than the instru-\\nment reads 53\\nX. Corneal astigmatism against the rule The patient accepts only\\n.25 D. more than the instrument reads 54\\nXI. Ophthalmometer shows corneal astigmatism against the rule, and\\nthe patient accepts .75 D. more than the instrument reads 55\\nXII. Ophthalmometer shows astigmatism against the rule; The\\npatient accepts the reading of the instrument exactly in one\\neye, but .25 D. less than the reading of the instrument in the\\nother, though the astigmatism is against the rule 55\\n411", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0429.jp2"}, "430": {"fulltext": "412 INDEX OF CASES\\nCase Page\\nXIII. No corneal astigmatism, but the patient accepts a .50 D.\\ncylindrical glass against the rule, at 180\u00c2\u00b0 56\\nXIV. No corneal astigmatism; The patient accepts cylindrical\\nglasses against the rule at different axes, 180\u00c2\u00b0 and 135\u00c2\u00b0\\nrespectively 58\\nXV. Ophthalmometer shows no corneal astigmatism; Patient\\naccepts a .25 D. cylindrical glass against the rule, axis\\n180\u00c2\u00b0 in each eye 60\\nXVI. Ophthalmometer shows no corneal astigmatism The patient\\naccepts .75 D. cylindrical glass against the rule, axis\\n180\u00c2\u00b0 in each eye 60\\nXVII. No corneal and no lenticular astigmatism, a moderate\\namount of latent hypermetropia 61\\nXVIII. Astigmatism with the rule, .25 D., axis 90\u00c2\u00b0 or 180\u00c2\u00b0\\naccording to the ophthalmometer Patient accepts a\\n.25 D. cylindrical glass, axis 180\u00c2\u00b0, against the rule 62\\nXIX. Corneal astigmatism with the rule, .25 D. Patient accepts\\n.25 cylindi ical glass against the rule and is relieved\\nof a marked asthenopia, with marked improvement in\\nvision 62\\nXX. Both axes slant 30\u00c2\u00b0 to the nasal side of the vertical meridian,\\nstanding at 60\u00c2\u00b0 in the right eye and at 120\u00c2\u00b0 in the left eye 67\\nXXI. Both of the shorter axes slant 15\u00c2\u00b0 to the temporal side of the\\nvertical meridian, standing at 105\u00c2\u00b0 in the right eye and at\\n75\u00c2\u00b0 in the left eye .68\\nXXII. Both axes slant but 5\u00c2\u00b0 to the temporal side of the vertical\\nmeridian, standing at 95\u00c2\u00b0 in the right eye and at 85\u00c2\u00b0 in\\nthe left eye 70\\nXXIIL Axis vertical or 90\u00c2\u00b0 in one eye, and 15\u00c2\u00b0 from the vertical in\\nthe other eye, standing at 75\u00c2\u00b0 71\\nXXIV. Both axes slant 15\u00c2\u00b0 in the same direction from the vertical\\nmeridian, to the temporal side in the right and to the\\nnasal side in the left, standing in each at 105\u00c2\u00b0 72\\nXXV. Astigmatism against the rule where the axes of the glasses\\nslant relatively the same number of degrees from the\\nhorizontal meridian, standing at 15\u00c2\u00b0 in one eye and at\\n165\u00c2\u00b0 in the other eye 73\\nXXVI. Astigmatism with axes at 45\u00c2\u00b0 and 135\u00c2\u00b0 75", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0430.jp2"}, "431": {"fulltext": "INDEX OF CASES 413\\nCHAPTER IV\\nCompound Hypermetropic Astigmatism Spasm of Accommodation\\nCase Page\\nXXVII. Ophthalmometer shows astigmatism with the rule, 1 D.\\nPatient accepts compomid plus glasses with relief of\\nasthenopia and conjunctivitis 84\\nXXVIII. Large amount of astigmatism with the axes slanting\\nrelatively the same number of degrees from the ver-\\ntical meridian, 15\u00c2\u00b0 to the nasal side, in each eye;\\nPatient accepts a compound plus glass with relief of\\nasthenopic symptoms 85\\nXXIX. Astigmatism against the rule, 1 D., with the axis 15\u00c2\u00b0 from\\nthe horizontal meridian in each eye; Patient accepts\\ncompound plus glasses and gets relief from asthenopia 86\\nXXX. Small amount of astigmatism associated with a large\\namount of hypermetropia Marked asthenopia Relief\\nwith glasses 87\\nXXXI. Hypermetropic astigmatism in each eye of equal amount,\\n2 D. Patient accepts a simple plus cylindrical glass\\nin one eye, and a compound plus glass in the other;\\nRelief from asthenopia 90\\nXXXII. Compound hypermetropic astigmatism against the rule in\\none eye Large amount of hypermetropia in the other\\neye Marked asthenopia Relief with the use of glasses 91\\nXXXin. Compound hypermetropic astigmatism with the chief\\nmeridians of curvature at 45\u00c2\u00b0 and 135\u00c2\u00b0; Marked as-\\nthenopia Relief with glasses 93\\nXXXIV. Large amount of compound hypermetropic astigmatism\\nwith the main meridians at 45\u00c2\u00b0 and 135\u00c2\u00b0; Severe\\nasthenopia Amblyopia Relief with glasses 96\\nXXXV. Astigmatism against the rule in one eye and with the rule\\nin the other; Marked asthenopia; Relief with glasses 98\\nXXXVI. Ophthalmometer shows no corneal astigmatism Patient\\naccepts .25 D. cylindrical glass against the rule in\\naddition to a spherical glass 99\\nXXXVII. The ophthalmometer shoM^s no corneal astigmatism Pa-\\ntient accepts -50 D. cylindrical glass against the rule 100\\nXXXVIII. Astigmatism with the rule, .25 D. Patient accepts 50\\nD. cylindrical glass against the rule with relief from\\nmarked asthenopia 102\\n1", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0431.jp2"}, "432": {"fulltext": "414 INDEX OF CASES\\nCase Pagk\\nXXXIX. Ophthalmometer shows corneal astigmatism with the rule,\\n.25 D. Patient accepts this amount exactly, indicating\\nno lenticular astigmatism whatever lOS\\nXL. Astigmatism with the rule, .25 D. Patient accepts .50 D.\\ncylindrical glass against the rule, in combination with\\n2 D.s Latent hypermetropia of 2 D. left uncorrected\\nMarked asthenopia Kelief with glasses 104\\nXLL Astigmatism with the rule, 1.50 D. in the right eye and\\n2 D. in the left, with 2 D. hypermetropia; Fitted with\\nglasses several times under a mydriatic, with but little\\nbeneht Complete- relief with glasses fitted by the aid\\nof the ophthalmometer without any mydriatic .105\\nXLn. Astigmatism of large amount, with moderately large\\namount of latent hypermetropia, which latter was left\\nuncorrected Complete relief of the asthenopia by cor-\\nrection of the astigmatism lOS\\nXLin. Compound hypermetropic astigmatism with the rule\\nSpasm of accommodation Amblyopia Atropine used,\\nand but little difference found between the glasses fitted\\nwithout atropine and those fitted under it 115\\nXLIV. Compound hypermetropic astigmatism against the rule;\\nSpasm of accommodation Mild conjunctivitis Hyper-\\nsesthesia of the retinae Scopolamine used 115\\nXLV. Hypermetropia of large amount; Spasm of accommoda-\\ntion Asthenopia Atropine used Relief with 3 D. of\\nlatent hypermetropia left uncorrected 117\\nXLYI. Simple hypermetropic astigmatism; Spasm of accommo-\\ndation; Marked asthenopia; Minus cylindrical glasses\\naccepted without atropine and perfect vision obtained\\nPlus cylindrical glasses accepted under atropine and\\nperfect vision 11\\nCHAPTER V\\nSimple Myopic Astigmatism Simple Myopia Presbyopia\\nXL VII. Simple myopic astigmatism with the rule; Blepharitis\\nmarginalis Slight asthenopia Relief of blepharitis\\nwith the use of glasses and local treatment 124\\nXL VIII. Simple myopic astigmatism with the rule Some amblyo-\\npia Relief with glasses 125\\n1\\ni", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0432.jp2"}, "433": {"fulltext": "INDEX OF CASES 415\\nCase Page\\nXLIX. Simple myopic astigmatism with the rule of large amount\\nAmblyopia, and a mild form of asthenopia 126\\nL. No corneal astigmatism Patient accepts .50 D. cylindri-\\ncal glasses against the rule Relief from asthenopia 127\\nLI. Simple myopic astigmatism with the rule in the right eye\\nLenticular astigmatism against the rule in the left eye,\\nthe ophthalmometer showing no corneal astigmatism\\nAsthenopia Relief with glasses 128\\nLII. Simple myopic astigmatism in one eye, and simple myopia\\nin the other Asthenopia Relief with glasses 129\\nLin. Corneal astigmatism with the rule, .50 D. Patient accepts\\nsirhple spherical glasses of high power for distance, and\\nweaker for reading; The rule for giving two pairs of\\nglasses in high degrees of myopia considered 131\\nLIV. Myopia of moderate amount in one eye and small amount\\nin the other Occasional divergent squint Asthenopia\\nRelief of the squint and asthenopia with correcting glasses 136\\nLV. Myopic astigmatism of moderate amount; Presbyopia;\\nSimple minus cylindrical glasses for the distance, and\\ncross-cylindrical glasses for reading 138\\nLVI. Simple myopic astigmatism with the rule Presbyopia\\nMinus cylindrical glasses for the distance, and plus cylin-\\ndrical glasses for the near work 138\\nLVII. Simple myopic astigmatism with the rule in one eye and\\nagainst the rule in the other Presbyopia Minus cylin-\\ndrical glasses for the distance and plus cylindrical glasses\\nfor reading 139\\nCHAPTER YI\\nCompound Myopic Astigmatism Antimetropia\\nLVni. A typical case of compound myopic astigmatism; Slight\\nasthenopia Vision brought up to perfect, f^, with glasses 119\\nLIX. Compound myopic astigmatism, where the myopia is con-\\nsiderable in amount and the astigmatism small in amount;\\nPatient is wearing spherical glasses Slight asthenopia,\\nwith poor vision Relief with glasses 151\\nLX. Compound myopic astigmatism, the myopia being large in\\namount, while the astigmatism is small in amount 152", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0433.jp2"}, "434": {"fulltext": "416 INDEX OF CASES\\nCase Page\\nLXI. Large amount of myopia with a moderate amount of astig-\\nmatism with the rule Axis of the astigmatism horizontal\\nin one eye and off from the horizontal in the other;\\nAsthenopia Relief with glasses 155\\nLXII. Large amount of myopia Small amount of astigmatism, but\\nmarked increase of vision by its correction Full correction\\nworn with comfort 156\\nLXTTT. Compound myopic astigmatism in one eye Simple myopia\\nof small amount in the other; Scopolamine used as a\\nmydriatic 157\\nLXIV. Compound myopic astigmatism in one eye; Simple myopic\\nastigmatism in the other Asthenopia marked Presbyopia 159\\nLXV. Antimetropia with blepharitis marginalis Simple hyper-\\nmetropic astigmatism in one eye, and simple myopic\\nastigmatism in the other, with the rule in each eye 165\\nLXYI. Antimetropia; Amblyopia to some extent; Simple hyper-\\nmetropic astigmatism in one eye, and simple myopic\\nastigmatism in the other, with the rule in each eye 167\\nLXVIL Antimetropia Asthenopia Simple hypermetropic astigma-\\ntism in one eye, and compound myopic astigmatism in the\\nother, with the rule in each eye 168\\nLXVIII. Antimetropia; Compound hypermetropic astigmatism in\\none eye and compound myopic astigmatism in the other,\\nagainst the rule in the myopic eye and with the rule in\\nthe hypermetropic eye Marked asthenopia relieved with\\nglasses 169\\nLXIX. Antimetropia Mixed astigmatism right and compound\\nmyopic astigmatism left eye Head carried to the right\\nside Asthenopia Relief with glasses .171\\nLXX. Antimetropia; Simple hypermetropia right eye; Simple\\nmyopia of large amount with convergent strabismus left\\neye Correction of strabismus with glasses without opera-\\ntion 173\\nCHAPTER Vn\\nMixed Astigmatism\\nLXXI. Mixed astigmatism of large amount and with the rule in\\neach eye Asthenopia Relief with glasses", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0434.jp2"}, "435": {"fulltext": "INDEX OF CASES 417\\nCase Page\\nLXXII. Mixed astigmatism of large amount, with the rule and\\nat off axes Marked asthenopia, severe headaches, dizzi-\\nness Relief with glasses 184\\nLXXIII. Mixed astigmatism with the rule; No amblyopia; Per-\\nsistent headaches Relief with glasses 186\\nLXXIY. Mixed astigmatism with the rule in one eye Hyperme-\\ntropic astigmatism with the rule in the other eye\\nAsthenopia Relief with glasses 187\\nLXXV. Mixed astigmatism with the rule right eye; Hyperme-\\ntropic astigmatism with the rule left eye Marked\\nasthenopia; Spasm of accommodation; Atropine in-\\nstilled Relief with glasses 190\\nLXXYI. Mixed astigmatism with the rule left eye; Compound\\nhypermetropic astigmatism with the rule right eye;\\nAsthenopia; Relief with glasses 192\\nLXXYII. Mixed astigmatism with the rule left eye Simple myopic\\nastigmatism with the rule right eye; Amblyopia;\\nAsthenopia Relief with glasses 193\\nLXXVin. Mixed astigmatism with the rule left eye Simple myopic\\nastigmatism with the rule right eye; Asthenopia;\\nFitted to glasses without atropine, although the child\\nwas but eight years old Relief with glasses 195\\nLXXIX. Mixed astigmatism with the rule right eye; Compound\\nmyopic astigmatism with the rule left eye; Constant\\npain in the eyes; Relief with glasses 196\\nLXXX. Mixed astigmatism with the rule in each eye, with the\\naxes slanting 5\u00c2\u00b0 from the vertical and horizontal meri-\\ndians in the same direction in each Asthenopia Relief\\nwith glasses 198\\nLXXXI. Mixed astigmatism against the rule right eye No\\ncorneal astigmatism left eye, but the patient accepts a\\nweak cylinder against the rule Patient is very nervous\\nMarked asthenopia Relief with glasses 200\\nLXXXII. Mixed astigmatism against the rule in each eye Spasm\\nof accommodation Marked asthenopia Relief with\\nglasses 202\\nLXXXIII. Mixed astigmatism of small amount against the rule in\\neach eye Presbyopia Asthenopia Blepharitis Relief\\nof asthenopia and blepharitis with glasses 204", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0435.jp2"}, "436": {"fulltext": "418 INDEX OF CASES\\nCHAPTER Yin\\nIrregular Astigmatism Coxical Corxea\\nCase Pagb\\nLXXXIV. Slight irregular astigmatism due to opacities of the\\ncornea Regular astigmatism Amblyopia Astheno-\\npia 211\\nLXXXV. Irregular astigmatism associated with a large amount of\\nregular astigmatism following perforating ulcer of the\\ncornea; Marked decrease both of the irregular and\\nregular astigmatism, with attendant increase of vision\\nin one year s time 212\\nLXXXn. Irregular astigmatism associated with regular astigma-\\ntism against the rule right eye Regular astigmatism\\nagainst the rule left eye; Asthenopia; Relief with\\nglasses 215\\nLXXXYII. Irregular astigmatism ui each eye; Large amount of\\nregular astigmatism in each eye of the mixed variety\\nSevere asthenopia Vision considerably improved and\\nasthenopia relieved with the correcting glasses 216\\nLXXXVIII. Regular astigmatism with the rule right eye Irregular\\nastigmatism associated with a large amount of regular\\nastigmatism with the rule of a mixed nature left eye;\\nAsthenopia 218\\nLXXXIX. Marked irregular astigmatism, with a large amount of\\nregular astigmatism with the rule right eye Regular\\nastigmatism against the rule left eye Asthenopia only\\nto a limited degree 218\\nXC. Irregular astigmatism very slight, associated with mixed\\nastigmatism of large amount against the rule left eye\\nEmmetropia right eye 219\\nXCI. Irregular astigmatism associated with a large amount of\\nregular astigmatism -vsith the rule in each eye Anti-\\nmetropia Trichiasis Asthenopia Relief with opera-\\ntion and glasses 220\\nXCII. Irregular astigmatism Regular astigmatism Blephari-\\ntis marginalis Partial relief with glasses 222\\nXCin. Irregular astigmatism associated with compound myopic\\nastigmatism against the rule left eye; Compound\\nmyopic astigmatism against the rule right eye;\\nAsthenopia Relief with glasses 223", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0436.jp2"}, "437": {"fulltext": "INDEX OF CASES 419\\nCase Page\\nXCIY. Conical cornea, extreme in the right eye and marked in the\\nleft; Irregular astigmatism; No improvement with\\nglasses in the right, but the vision was brought from\\nto If with glasses in the left eye 227\\nCHAPTER IX\\nStrabismus Insufficiencies of the Recti Muscles\\nXCY. Convergent strabismus left eye Simple hypermetropia both\\neyes Cure by means of glasses and a mydriatic 271\\nXCVI. Periodic convergent strabismus right eye Simple hyperme-\\ntropia each eye Cure effected in three months by means\\nof glasses alone 273 J\\nXCVII. Convergent strabismus right eye Compound hypermetropic\\nastigmatism both Amblyopia both, but more marked in\\nthe right Glasses and one operation necessary for a cure 275\\nXCYIII. Convergent strabismus right eye Large amount of com-\\npound hypermetropic astigmatism in each eye, more\\nmarked in the right eye Amblyopia in each Cured by\\nglasses and one operation 276\\nXCIX. Marked convergent strabismus in each eye, more pronounced\\nin the right (50\u00c2\u00b0 right and 25\u00c2\u00b0 left) Power of fixation\\nlost in the right and in the left motion outward is limited\\nalso, the patient carrying her head to the left in order\\nto see straight ahead; Small amount of hypermetropia;\\nCured by tenotomy of the internal recti muscles, and ad-\\nvancement of the right external rectus 277\\nC. Divergent strabismus right eye Antimetropia Compound\\nmyopic astigmatism right and compound hypermetropic\\nastigmatism left eye; With glasses the squint was re-\\nlieved and single binocular vision obtained for distant\\nvision, but not for near 2S0\\nCI. Divergent strabismus right eye Simple hypermetropic astig-\\nmatism in both Correction of refractive error Tenotomy\\nright external rectus Relief 2S1\\nCII. Divergent strabismus right eye Myopia of high degree right,\\nand moderate degree left Glasses Tenotomy right exter-\\nnal rectus without advancement of the internal rectus Cure 2S3 i\\nCHI. Convergent strabismus right eye marked, and to a moderate\\ndegree in the left Hypermetropia right, compound hyper-\\nmetropic astigmatism left eye Glasses Tenotomy of\\ninternal rectus of each eye Cure 2S-i", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0437.jp2"}, "438": {"fulltext": "420\\nINDEX OF CASES\\nCase\\nCIV. Divergent strabismus right eye; Myopia of large amount\\neach eye Correction of myopia with glasses Tenotomy of\\nright external rectus,* with advancement of right internal\\nrectus Cure\\nPeriodic convergent strabismus at the age of forty-one, fol-\\nlowing a fixed squint of childhood; Never had glasses or\\noperation Simple hypermetropia Squint is non-comitant,\\nthough not paralytic Binocular single vision for distance,\\nbut not for near\\nPeriodic convergent strabismus in childhood recovered from\\nat the age of thirty-one without glasses or operation Large\\namount of compound hypermetropic astigmatism in each\\neye, with marked amblyopia in the left eye Asthenopia\\nRelief with glasses\\nInsufficiency of the internal recti muscles simple hyper-\\nmetropia of small amount Asthenopia Correction of\\nrefractive error Tonics Relief\\nCVni. Marked insufficiency of the internal recti; Simple hyper-\\nmetropia of moderate amount Asthenopia Correction of\\nthe refractive error Tonics Relief\\nCIX. Insufficiency of the internal recti muscles; Simple hyper-\\nmetropic astigmatism; Asthenopia; Correction of the re-\\nfractive error Relief\\nex. Insufficiency of all the recti muscles Relatively, the external\\nrecti were weaker than the others, as an homonymous di-\\nplopia was present at times Compound hypermetropic as-\\ntigmatism Correction of refractive error Tonics Relief\\ncv.\\nCVI.\\nevil.\\nPasb\\n286\\n287\\n289\\n290\\n291\\n293\\n294\\nCXI. Insufficiency of all of the recti muscles Troublesome homon-\\nymous diplopia Compound hypermetropic astigmatism\\nAsthenopia; Dizziness; Correction of refractive error;\\nTonic given, and less work ordered Relief 295\\nCXII. Insufficiency of the internal recti Simple hypermetropic\\nastigmatism; Occasional crossed diplopia; Dizziness;\\nMarked asthenopia Correction of refractive error and\\ntonics without relief; Prisms added to glasses without\\nrelief, but with the development of divergent squint;\\nOperation; Relief 297\\nCXIII. Insufficiency of the internal recti muscles Occasional diplo-\\npia for the near point Hypermetropia of small amount,\\nwith slight astigmatism in the left eye Marked astheno-", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0438.jp2"}, "439": {"fulltext": "INDEX OF CASES\\n421\\nCase\\npia; Glasses, tonics, prism exercises, open-air exercises,\\nand rest, all fail to relieve; Tenotomy of the right exter-\\nnal rectus, followed in two and one-half years with tenotomy\\nof the left external rectus, effect a cure\\nPage\\n298\\nCXIV. Insufficiency of the internal recti; Asthenopia; Photopho-\\nbia; Neuralgia; Emmetropia; Reading glasses ordered;\\nTonics; Improvement in the eyes, but not entire relief\\nfrom asthenopic symptoms 301\\nCXY. Insufficiency of the internal recti Small amount of hyper-\\nmetropia; Presbyopia; Asthenopia; Correction for near\\nwork Tonics Exercise Kelief 302\\nCXVI. Insufficiency of the internal recti; Mixed astigmatism in\\none eye, and compound hypermetropic astigmatism in the\\nother Occasional diplopia at the near point Severe head-\\naches Has had a number of graduated tenotomies Cor-\\nrection of refractive error Tonics; Relief. 803\\nCXVII. Insufficiency of the internal recti; Occasional diplopia;\\nAsthenopia; Ilypermetropia and Presbyopia; Reading\\nglasses Tonics Relief 304\\n\u00e2\u0080\u00a2CXVIII. Insufficiency of the internal recti made w^orse by wearing-\\nstrong prisms, bases in Incapacitated for work on account\\nof the great pain in the eyes and head Compound myopic\\nastigmatism; Mild trachoma; By taking off the prisms\\nand giving the proper glasses, the patient got entire relief,\\nand was able to resume his professional calling, that of a\\nlawyer 305\\nCHAPTER X\\nAstigmatism after Cataract Extraction\\nCXIX. Astigmatism against the rule, 3.50 D., axis ISO two weeks\\nafter operation 1.50 D., axis 180\u00c2\u00b0, six weeks after extrac-\\ntion Patient accepts 4- 10 D. .75 D. cyL, 180\u00c2\u00b0, and gets\\nII vision, six weeks after operation\\nCXX. Astigmatism of large amount, 8.50 D., against the rule, axis\\n15\u00c2\u00b0, two weeks after operation 7 D., axis ISO seven\\nweeks after operation fj V. with -f 10 1). -f 5 D. cyl.,\\n180\u00c2\u00b0, seven weeks after the operation\\n328", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0439.jp2"}, "440": {"fulltext": "422\\nINDEX OF CASES\\nCase Page\\nCXXI. Astigmatism of large amomit, 6 D., against the rule, two\\nweeks after operation Reduced to 1.50 D., two months\\nafter operation Patient at that time accepted all of the\\nastigmatism indicated by the ophthalmometer and got\\nf4 vision 329\\nCXXII. Astigmatism with the rule, 1.50 D., twelve days after\\noperation Astigmatism did not change in amount or\\naxis Patient accepted the full amount of astigmatism\\nindicated by the instrument, and obtained V. when\\ncombined with the proper spherical glass 330\\nCXXIII. Astigmatism against the rule, 3 D., three weeks after\\noperation 1 D., six weeks after operation No cylinder\\naccepted on the final test 331\\nCXXIV. Astigmatism of very large amount, 16 D., against the\\nrule, two and one-half weeks after operation 4 D., three\\nmonths after operation Patient accepts 3.50 D. cylinder\\nwith proper sphere, and gets V., after three months\\nCXXV. Astigmatism of large amount, 15 D., against the rule,\\nthree weeks after the operation Reduced to 13 D.\\nafter two months, and only to 12 D. after one year and\\na half, leaving 12 D. astigmatism permanently; Pa-\\ntient accepted 11.50 D. cylinder combined with 4 D.\\nsphere Axis of the astigmatism did not change in the\\nfirst two months, but had made a change of 15\u00c2\u00b0 when\\nseen in eighteen months\\n332\\n333\\nCXXVI. Astigmatism of excessive amount, 20 D., against the rule,\\nfrom incarceration of the iris in the wound during heal-\\ning; Patient accepted 16 D. cy]., without any sphere,\\ntwenty-six days after extraction 335-\\nCXXVII. Astigmatism of very large amount, 22 D., against the rule,\\ntwo weeks after operation 5 D., against the rule, five\\nmonths after operation, at which point it remained\\nstationary Change in axis of 10\u00c2\u00b0 during healing 337\\nCXXVIII. Astigmatism against the rule, 3 D., two and one-half weeks\\nafter operation Astigmatism with the rule, 2 D., three\\nmonths after operation, which remained as such for\\nabout four years, when the patient was last seen\\nOphthalmometer showed no corneal astigmatism what-\\never before the extraction 338^", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0440.jp2"}, "441": {"fulltext": "INDEX OF CASES\\n423\\nCase Page\\nCXXIX. Astigmatism against the rule, 10 D., four weeks after\\noperation; Six months after operation, astigmatism\\nwith the rule, 4.50 D., which four months later (and\\nten months after operation) had diminished to about\\n1 D. with the rule 338\\nCXXX. Astigmatism with the rule, 4.50 D,, three and one-half\\nweeks after operation Changed to 1.50 D. against the\\nrule, after three years, and remained thus at the end of\\nfive years from, operation Case remarkable also for\\nacuteness of vision obtained, f\u00c2\u00a7, and for accommodative\\npower after the extraction of the lens 339\\nCXXXI. Astigmatism with the rule, 3 D., three weeks after opera-\\ntion; 1.50 D., against the rule, three months after;\\nAccepts 1 D., cylindrical glass, with sphere for dis-\\ntance, but no cylinder for reading 341\\nCXXXII. Astigmatism against the rule, with a change in the axis of\\n30\u00c2\u00b0 within one week s time, due perhaps to stretching\\nof the wound from needling, which was performed one\\nmonth after the extraction 341\\nCXXXIII. Astigmatism 6 D., axis 45\u00c2\u00b0; Section was made directly\\nabove for the extraction, but the nasal side of the wound\\n(left eye) broke open during a needling on the twelfth\\nday Ultimate vision 342\\nCHAPTER XI\\nExceptional Cases\\n(1) Cases showing discrepancies as to the amount of the astigmatism\\nCXXXIV. Corneal astigmatism, 2.50 D., with the rule; Total astig-\\nmatism, 1.25 D., by subjective examination SGO\\nCXXXV. Corneal astigmatism with the rule, 1 D. right and 1.50 D.\\nleft eye. Patient will accept no cylindrical glass;\\nAntimetropia Presbyopia oGl\\nCXXXVI. Congenital absence of the iris Corneal astigmatism with\\nthe rule, 1.50 D. right and 2 D. left, axis 5\u00c2\u00b0 and 175\u00c2\u00b0,\\nrespectively Total astigmatism 1 D. each, with the same\\naxes as the corneal astigmatism In eighteen months\\ntime the corneal astigmatism did not change, but the\\ntotal increased to 2.50 D. in each eye, axis 180\u00c2\u00b0 each,\\ndue to slight luxation upward and tilting backward of\\nthe upper edges of the crystalline lenses 362", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0441.jp2"}, "442": {"fulltext": "424\\nINDEX OF CASES\\n(2) Cases showing variation as to the axes of the corneal astigmatism\\nand total astigmatism\\nCase Page\\nCXXXVII. Corneal astigmatism with the rule, axis 90\u00c2\u00b0 or 180\u00c2\u00b0\\nin each eye Patient accepts minus cylindrical glasses,\\naxis 15\u00c2\u00b0 right eye, and 30\u00c2\u00b0 left eye 364\\nCXXXVIII. Ophthalmometer shows corneal astigmatism with the\\nrule, 60\u00c2\u00b0 or 150\u00c2\u00b0 left eye Patient accepts a plus\\ncylinder axis 30\u00c2\u00b0, that is, 30\u00c2\u00b0 distant from the point\\nindicated by the instrument 365\\n(3) Cases with discrepancies both as to the axis and the amount of\\nthe astigmatism\\nCXXXIX. Corneal astigmatism with the rule in each eye Total\\nastigmatism is against the rule and at different axis\\nfrom that of the corneal astigmatism; Marked as-\\nthenopia; Relieved by the glasses accepted on sub-\\njective examination, which glasses were not according\\nto the reading of the ophthalmometer 365\\nCXL. Corneal astigmatism with the rule, .50 D. Patient\\naccepts .50 D. cylindrical glass against the rule in each\\neye 367\\nCXLI. Large amount of corneal astigmatism against the rule,\\nwith some irregular astigmatism Patient accepted\\ncross cylinders not at right angles to each other, the\\naxis of the minus cylinder being worn 30\u00c2\u00b0 and that of\\nthe plus cylinder 45\u00c2\u00b0 removed from the point indicated\\nby the ophthalmometer Vision markedly improved\\nwith the glasses, and binocular single vision restored 367\\nCXLII. Corneal astigmatism with the rule; Patient accepts\\ncylindrical glasses against the rule 369\\nCXLIII. Corneal astigmatism against the rule Total astigmatism\\nagainst the rule, but with the axis of the cylinder 15\u00c2\u00b0\\nfrom the point indicated by the instrument, right eye\\nNo corneal astigmatism, but total astigmatism of\\n1.25 D., left eye 369\\nCXLIV. No corneal astigmatism right eye Corneal astigmatism\\nagainst the rule 180\u00c2\u00b0 or 90\u00c2\u00b0 left eye, but the\\npatient accepts a plus cylinder at 150\u00c2\u00b0 instead of 180\u00c2\u00b0\\nas indicated by the ophthalmometer Spasm of accom-\\nmodation Mydriatic used 371", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0442.jp2"}, "443": {"fulltext": "INDEX OF CASES\\n425\\nCase\\nCXLV. Lenticonus anterior Corneal astigmatism with the rule,\\n2 D. in each eye Total astigmatism is against the\\nrule, 5.50 D. in right, and 4 D. in the left eye Vision\\ngreatly improved with glasses\\nCXLVI. Corneal astigmatism with the rule .25 D. On subjective\\nexamination the patient accepted plus .25 D. cylin-\\ndrical glasses against the rule In four years time the\\naxis of the corneal astigmatism and the axis of the\\ntotal astigmatism, as brought out by subjective exam-\\nination, had changed 30\u00c2\u00b0\\nCorneal astigmatism with the rule, with the principal\\nmeridians not at right angles\\nPage\\n372\\nCXLVII.\\nCXLVIII.\\nCorneal astigmatism with the principal meridians not at\\nright angles in the right eye, but at right angles in the\\nleft eye\\nCXLIX. Large amount of astigmatism, the corneal and total cor-\\nresponding closely as to amount and exactly as to axis\\nPatient accepts the glasses as indicated by the ophthal-\\nmometer with marked improvement in vision, but can-\\nnot wear any cylindrical correction, preferring simple\\nspheres\\nCL. Corneal astigmatism against the rule, with oblique or\\nslanting axis Total astigmatism exactly the same as\\nto axis and almost identical as to amount Patient s\\nvision is greatly improved with cylindrical correction,\\nyet he cannot wear it\\n375\\n376\\n377\\n378\\n380", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0443.jp2"}, "444": {"fulltext": "", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0444.jp2"}, "445": {"fulltext": "GENERAL INDEX\\nAbduction, 257, 264.\\nAccessory effects of strong myopic\\nglasses, 147, 153, 154, 155.\\nAccommodation, paresis of, as a cause\\nof strabismus, 238, 241.\\nspasm of, 109.\\nAdduction, 257, 264.\\nAdjustment of glasses, 317.\\nAgainst the rule, its meaning, 23.\\nAlternating strabismus, 275.\\nAmblyopia, 83, 235.\\nAmount or degree of astigmatism, 36\\net seq.\\nafter cataract extraction, 314, 315.\\nAmplitude of convergence, 259.\\nAngle aljJha, 242.\\nas an accessory cause of strabismus,\\n242.\\nas a cause of apparent strabismus,\\n247.\\nas a cause of astigmatism, 355.\\nits effect on the readings of the\\nophthalmometer, 250.\\nnegative, 244.\\nnil, 244.\\npositive, 243.\\nAngle gamma^ as a cause of astigma-\\ntism, 357.\\nAniridia, 352, 362.\\nAnisometropia, 163.\\nAnthnetropia, 147, 163.\\nApparent strabismus, 247.\\nAppendix, 383-410.\\nArc, graduated, 3, 8.\\nArlt, Adolph, 278.\\nArtificial cornea, Javal s, 392.\\nMorgan s, 393.\\n-Astigmatism against the rule, 23.\\ncompound H., 24.\\nAstigmatism against the rule, com-\\npound M., 25.\\nmixed, 26.\\nsimple H., 23.\\nsimple M,, 25.\\nAstigmatism with the rule, 19.\\ncompound H., 21.\\ncompound M., 22.\\nmixed, 23.\\nsimple H., 21.\\nsimple M., 21.\\nAstigmatism, amount of, 36, 37, 38, 39.\\nafter cataract extraction, 314, 315.\\nAstigmatism, axis of, 36, 37, 38, 39.\\nafter cataract extraction, 316, 317,\\n343, 344.\\nAstigmatism, after cataract extraction,\\n308.\\ncorneal, 13 et seq.\\ncompound hypermetropic, 80.\\ncompound myopic, 148.\\ndirect, 20.\\ndynamic, 352.\\nindirect, 20.\\nirregular, 209.\\nlenticular, 31, 351.\\nlenticular irregular, 353.\\nlenticular regular, 352.\\nmixed, 175.\\nof the posterior surface of the cor-\\nnea, 358.\\nsimple hypermetropic, o6.\\nsimple myopic, 122,\\nAtropine, its use in refraction, 82 ct seq.\\nAxial or true myopia, 123.\\nAxis of astigmatism, 36, 37, 38, 39.\\nafter cataract extraction, 316, 317,\\n343, 344.\\nB\\nBannister, 263, 264, 265.\\nBase of the ophthalmometer, 3, 391.\\n427", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0445.jp2"}, "446": {"fulltext": "428\\nGENERAL INDEX\\nBi-cylindric lenses, 323.\\nBi-refractive prism (Wallaston s), 5.\\nBlack, George M., 333, 351.\\nBaffon, 238.\\nBull, George J., 40, 326, 410.\\nBurnett, S. M., 1, 3, 234.\\nChapman, 390, 399.\\nChief meridians at 45\u00c2\u00b0 and 135\u00c2\u00b0, S3.\\nChromatic aberration, 318.\\nClaiborne, J. H., 65, 200.\\nColeman, W. E., 255.\\nCollimation, 357.\\nCompound hypermetropic astigmatism,\\n80.\\nmyopic astigmatism, 148.\\nConical cornea, 209, 225.\\nConstruction of the ophthalmometer,\\n(Javal-Schiotz), 3 et seq.\\n(Reid s), 394.\\n(Hardy s), 401.\\nContact lenses, 209, 233.\\nContraction of the ciliary muscle, as a\\ncause of astigmatism, 352, 353.\\nof the recti muscles, as a cause of\\nastigmatism, 358.\\nConvergence, amplitude of, 259.\\nConvergent strabismus, 235 et seq.\\nCornea, conical, 209, 225.\\nCross-threads, 5.\\nCurvature myopia, 124.\\nD\\nDavis s double-movable mires, 383.\\nDecentering of lenses, 308, 317.\\nDennett, W. S., 40, 268, 391.\\nDeorsumduction, 258, 266.\\nDe Schweinitz, George, 3.\\nDescription of the ophthalmometer,\\n(Hardy s), 401.\\n(Javal-Schiotz) 3, et seq.\\n(Reid s), 394.\\nDeviation, primary, 271.\\nDeviation, secondary, 271.\\nby Wallaston bi-refractive prism,\\n6, 7.\\nDeynard, A. B., 263.\\nDiopter, 133, 134.\\nDioptric system of numbering glasses,.\\n133, 134.\\nDirect astigmatism, 20.\\nDivergent strabismus, 235 et seq.\\nDobrowlsky, 352, 353.\\nDodd, 314, 336.\\nDonders, 38, 141, 235, 236, 237, 238,\\n239, 241, 242, 243, 245, 248, 322,\\n352, 353, 356, 367, 379.\\nDuane, 240, 265.\\nE\\nEffect of the recti muscles on the cur-\\nvature of the cornea, 275.\\nEly, E. T., 254.\\nEmerson, J. B., 254, 327, 331, 332.\\nEquilibrium test of the muscles, 259.\\nFalse or spasmodic myopia, 123.\\nFaulty observation, as a cause of error\\nin the readings of the ophthal-\\nmometer, 350.\\nFoster, M. L., 83.\\nFuchs, 253, 271, 278.\\nG\\nGeneral considerations in the use of the-\\nophthalmometer, 36.\\nGiles, J. E., 390, 399.\\nGlasses, contact, 209, 233.\\nhyperbolic, 209, 232, 233.\\nperiscopic, 309, 326.\\ntoric, 309, 323.\\nGraduated arc, the, 3, 8.\\nGraefe, Alfred, 255.\\nGraefe, Von, 255, 257, 259.\\nGreen, John, 3, 78, 319, 323, 325, 326..\\nGuide-lines, 9.\\nH\\nHamer, 243, 248.\\nHarkness, William, 318, 319.\\nHarlan, G C, 255, 325, 326.\\nHelmholtz, 1, 226, 356, 357, 398, 401.\\nHirchberg, 40, 350.\\nHistory of the ophthalmometer, 1 et seq.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0446.jp2"}, "447": {"fulltext": "GENERAL INDEX\\n429\\nHolden, W. A., 317, 321, 322.\\nHolt, 255.\\nHomatropine, 80.\\nHyperbolic lenses, 209, 232, 233.\\nHypermetropia, 36.\\nas a cause of convergent strabismus,\\n237.\\nHypermetropic astigmatism, compound,\\n80 simple, 36.\\nagainst the rule, compound, 24.\\nagainst the rule, simple, 23.\\nas a cause of convergent strabis-\\nmus, 239.\\nwith the rule, compound, 21.\\nwith the rule, simple, 21.\\nI\\nIllumination of lines, 78, 79.\\nImperfect instruments, as a cause of\\nfaulty observations, 359.\\nImprovements on the ophthalmometer,\\n383.\\nIncongruous strabismus, 247.\\nIndex of cases, 411-425.\\nIndicator, long, 10.\\nshort, 10.\\nIndirect astigmatism, 20.\\nInsufficiencies of the ocular muscles,\\n235, 255.\\nJaval, 19, 49, 209, 238, 251, 253, 255,\\n311, 312, 313, 314, 348, 350, 351,\\n392, 398, 399, 401, 406, 410.\\nJaval, A., Jr., 38, 39, 358.\\nJaval-Schiotz ophthalmometer, 1 et seq.\\nconstruction of, 3.\\nhistory of, 1.\\nimprovements on, 383.\\nmodifications of, 391.\\nprinciple of application, 13.\\nrules for its use, 16.\\nJohnson, W. B., 253.\\nK\\nKinney, C. W., 365, 369.\\nKnapp, H., 200, 255, 257, 356, 357.\\nKoUer, K., 3.\\nLandolt, 134, 259, 262.\\nLatent strabismus, 256.\\nLaurence, 270.\\nLenses, see Glasses.\\nLenticonus, as a cause of astigmatism,\\n355.\\nreport of a case, 372.\\nLenticular astigmatism, 350 et seq.\\nirregular, 352, 353, 354, 355.\\nregular, 352, 353.\\nLewis, F. N., 40, 327, 338, 339.\\nM\\nMethods of testing the ocular muscles,\\n258 et seq.\\nMires, 3, 9.\\nMixed astigmatism, 175.\\nagainst the rule, 26.\\nwith the rule, 23.\\ntransposition of glasses in, 181, 183,\\n206.\\nMiiller, 238, 247.\\nMurdock, 399.\\nMydriatics, their use, 40 et seq.\\nMyopia, 122 et seq.\\nafter cataract extraction, 345.\\nas a cause of divergent strabismus,\\n240.\\naxial or true, 123.\\ncurvature, 124.\\nfalse or spasmodic, 123.\\nin high degrees, 132.\\nmalignant or progressive, 135, 149.\\nrules for giving glasses, 134.\\nwhen presbyopia is present, 140.\\nMyopic astigmatism, compound, 148\\nsimple, 122.\\nagainst the rule, compound, 25.\\nagainst the rule, simple, 25.\\nwith the rule, compound, 22.\\nwith the rule, simple, 21.\\nN\\nNelson, J. E., 279.\\nNordenson, 350.\\nNorris, 3.\\nNoyes, H. D., 3, 257, 265.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0447.jp2"}, "448": {"fulltext": "430\\nGENERAL INDEX\\nk\\nO\\nObjective, 5.\\nOliver, C. A., 399.\\nOphthalmometer (Javal-Schiotz), 1 et\\nseq.\\n(Chambers and Inkeep s), 391.\\n(Hardy s), 401 et seq.\\nhistory of, 1.\\nimprovements on, 383.\\nits construction, 3.\\n(Kagenaar s), 410.\\nMeyro^Yitz s model of, 391.\\nprmciple of application, 13.\\n(Reid s), 394 et seq.\\nrules for its use, 16.\\nOphthalmophakometer, 358.\\nOverlapping of the mires, its cause, 27.\\nPayne, S. ^l., 257.\\nPercival, 345.\\nPeriscopic lenses, 309, 325, 326.\\nPfingst, E. 0., 314, 315, 316, .335.\\nPlacido, 21, 209, 211, 229, 357, 391, 392.\\nPlanchette, 3.\\nPolyopia monocularis, 355.\\nPomeroy, O. D., 327, 330, 341.\\nPooley, T. E., 83.\\nPosition of the glasses in front of the\\neyes, its influence, 335.\\nPresbyopia, transposition of glasses\\nwhen myopia is present, 159 et seq.\\nPresbyopic glasses for myopes, 140.\\nPrimary deviation, 271.\\nposition, 17.\\nPrincipal meridians at 45\u00c2\u00b0 and 135\u00c2\u00b0, 33.\\nPrinciple of the application of the\\nophthalmometer, 13.\\nPrisms, bi-refractive (Wallaston), 5.\\ntheir use in testing the ocular mus-\\ncles, 257 et seq.\\nProgressive myopia, 135, 149.\\nglasses for, 153, 155.\\nhygienic treatment of, 155.\\nR\\nEadius of curvature of the cornea, 37.\\nRaehlmann, 232, 233.\\nEeflector, 3.\\nEeid, 210, 226, 312, 313, 359, 399.\\nEeid s ophthalmometer, 394.\\nRetinoscopy, 58.\\nEeute, 238.\\nEing, F. W., 3.\\nEisley, S. D., 255, 263, 264.\\nEoosa, St. John, 3, 40, 238, 239, 254,\\n255, 256, 263, 327, 335.\\nEoutine examination of the eyes, 41\\net seq.\\nEules for the use of the ophthalmome-\\nter, 16.\\nS\\nSchiotz, 38, 39, 209, 313, 350, 398, 399,\\n401, 406.\\nScopolamine, 82.\\nSecondary deviation, 271.\\nposition, 18.\\nSeparation of the mires, its cause, 27.\\nSimi3le hypermetropia, 36.\\nhypermetropic astigmatism, 36.\\nSkeel s perpendicular lever adjustment,\\n390.\\nSkiascopy, 58.\\nSmith, ^Y. H., 83.\\nSnellen, 200, 340.\\nSpasm of accommodation, 109.\\nSpasmodic mj opia, 123.\\nSpeakman, 3.\\nSpherical aberration. 319.\\nas a cause of error in the readings\\nof the ophthalmometer, 359.\\nStarr, M. A., 264.\\nStevens, George T., 257, 259, 263.\\nStrabismus, 235.\\nalternating, 275.\\napparent, 247.\\nconvergent, 235 et seq.\\ndivergent, 235 et seq.\\nincongruus, 247.\\nlatent, 256.\\nStrabometer, 270.\\nSulzer, 388.\\nSursumduction, 258, 266.\\nTelescope of the ophthalmometer, 3.\\nTenon, 282.\\nTilting of lenses, 319 et seq.", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0448.jp2"}, "449": {"fulltext": "GENERAL INDEX\\n431\\nToric lenses, 309, 323.\\nTransposition of glasses, in myopia,\\n142, 143, 144.\\nin myopes who have become pres-\\nbyopic, 159.\\nof glasses, in mixed astigmatism,\\n181, 183, 206.\\nTropometer, 257.\\nTrue or axial myopia, 123.\\nV\\nValk, Francis, 3, 37, 39, 389.\\nYalk s gear wheel attachment, 389.\\nVan Eleet, Frank, 3, 62.\\nVariation in position of the principal\\nmeridians of curvature of the\\ncornea, 65.\\nW\\nWallaston s bi-refractive prism, 5.\\nWebster, David, 133, 327, 341, 342.\\nWecker, 210.\\nWeiland, C, 3, 311, 312, 351, 355.\\nWhy the mires overlap, 27.\\nseparate, 27.\\nWhy we deduct 50 D. from the read-\\ning of the ophthalmometer in\\nastigmatism with the rule, 29.\\nWhy we add 50 D. to the reading of the\\nophthalmometer when the astig-\\nmatism is against the rule, 29.\\nWith the rule, its meaning, 19.\\nWoodward, 3.\\nWtirdeman, 3.", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0449.jp2"}, "450": {"fulltext": "i", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0450.jp2"}, "451": {"fulltext": "DEFECTIVE EYESIGHT\\nThe Principles of its Relief by Glasses\\nBY\\nD. B. ST. JOHN ROOSA, M.D., LL.D.\\nProfessor Evieritus of Diseases of the Eye and Ear, Post- Graduate Medical\\nSchool and Hospital Stirgeoti to the Manhattan Eye and Ear Hospital\\netc., etc. Author of A Clinical Manual of Diseases of the Eye\\nOphthalmic and Otic Memoranda A Practical Treatise\\non the Diseases of the Ear The Old Hospital and Other\\nPapers A Vest-Pocket Medical Lexicon\\nCloth. i6mo. Price $i.oo, net\\nThe author is one of the most noted speciahsts in diseases of the\\neye in the world, and anything which emanates from his pen is sure to\\nbe authoritative. The volume before us is filled with valuable material\\nwhich cannot but prove of the greatest possible value to all who deal\\nwith defective eyesight. It is accompanied by many excellent illustra-\\ntions and test charts. Scientific American.\\nIt is written in the terse style of the distinguished author, and al-\\nthough it is an interesting book for the layman to read, it is also a hand-\\nbook quite complete enough to be a guide to the general practitioner,\\nand even to the specialist in ophthalmology.\\nMedical Revieiu of Reviews.\\nIt appeals to the ophthalmic practitioner, but also to the general\\nphysician who wants to familiarize himself with the diagnosis and man-\\nagement of the errors of refraction, especially the proper selection of\\nspectacles. Af-ch. of Ophthalmology.\\nTHE MACMILLAN COxMPANY\\n66 FIFTH AVENUE, NEW YORK CITY", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0451.jp2"}, "452": {"fulltext": "HANDBOOK OF OPTICS\\nFOR\\nSTUDENTS OF OPHTHALMOLOGY\\nBY\\nWILLIAM NORWOOD SUTER, B.A., M.D.\\nProfessor of Ophthalmology, Natio7ial University, and Assistant Surgeon\\nEpiscopal Eye, Ear, and Throat Hospital, Washington, D.C,\\nCloth. i6mo. Price $i.oo, net\\nL\\nCONTENTS\\nIntroduction.\\nCHAPTER\\nI. Refraction at Plane Surfaces.\\nII. Refraction at Spherical Surfaces.\\nIII. Refraction through Lenses.\\nIV. The Eye as an Optical System.\\nV. The Determination of the Cardinal Points of the Eye in Combination\\nwith a Lens.\\nVI. Errors of Refraction-lenses used as Spectacles.\\nVII. The Effect of Spherical Lenses upon the Size of Retinal Images.\\nVIII. Cylindrical Lenses.\\nIX. The Twisting Property of Cylindrical Lenses.\\nX. The Sphero-cylindrical Equivalence of Bicyhndrical Lenses.\\nXI. Oblique Refraction through Lenses.\\nXII. The Effect of Prismatic Glasses upon Retinal Images.\\nXIII. The Reflexion of Light.\\nXIV. The Optical Principles of Ophthalmometry and of Ophthalmoscopy.\\nAppendices.\\nTHE MACMILLAN COMPANY\\n66 FIFTH AVENUE, NEW YORK CITY", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0452.jp2"}, "453": {"fulltext": "", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0453.jp2"}, "454": {"fulltext": "", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0454.jp2"}, "455": {"fulltext": "\u00c2\u00ab!T", "height": "4290", "width": "2806", "jp2-path": "refractionofeye00davi_0455.jp2"}, "456": {"fulltext": "LIBRARY OF CONGRESS\\n021 068 970 9", "height": "4257", "width": "2805", "jp2-path": "refractionofeye00davi_0456.jp2"}}