THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA LOS ANGELES A TREATISE ON GLAUCOMA BY THE SAME AUTHOR SCLERO-CORNEAL TREPHINING IN THE OPERATIVE TREATMENT OF GLAUCOMA, 1913. Second Edition, 1914. George Pulman & Sons Ltd., London. GLAUCOMA: DIGEST OF THE YEAR'S LITERATURE. The Ophthalmic Year Book, 1913-1916. Herrick Book and Stationery Company, Denver, Colorado, U.S.A. GLAUCOMA: A HANDBOOK FOR THE GENERAL PRACTITIONER. H. K. Lewis & Co. Ltd., London. 1917. THE INDIAN OPERATION OF COUCHING FOR CATARACT, incorporating the Hunterian Lectures, delivered before the Royal College of Surgeons of England, on February 19 and 21, 1917. H. K. Lewis & Co. Ltd., London. 1917. TROPICAL OPHTHALMOLOGY. Henry Frowde and Hodder & Stoughton, The Lancet Building, i Bedford Street, Strand, London, W.C. 2. 1920. LECTURES ON TROPICAL OPHTHALMOLOGY, delivered at the London School of Tropical Medicine. Henry Frowde and Hodder & Stoughton, The Lancet Building, i Bedford Street, Strand, London, W.C. 2. 1920. THE CARE OF EYE CASES: A Manual for the Nurse, Practitioner, and Student. Henry Frowde and Hodder & Stoughton, The Lancet Building, i Bedford Street, Strand, London, W.C. 2. 1921. GLAUCOMATOUS CUPPING OK THE OPTIC Disc. Both Illustrations show well (1) the bending of the vessels over the edges of the discs. (2) the haloes of surrounding choroidal atrophy, and (3) the stippling of the floors of the cups. (Reproduced by kind permission of Mr. Adams Frost from his OphthaJ.moscopic Atlas, Oxford Medical Publications. London.) OXFORD MEDICAL PUBLICATIONS A TREATISE ON GLAUCOMA BY ROBERT HENRY ELLIOT M.D., B.S.(Lond.), Sc.D.(Edin.), F.R.G.S.(Eng.) LiEur.-Coi.ONEL I. M.S. (RETIRED) LATE SUPERINTENDENT OF THE GOVERNMENT OPHTHALMIC HOSPITAL, MADRAS LATE PROFESSOR OF OPHTHALMOLOGY, MEDICAL COLLEGE, MADRAS; AND LATE FELLOW OF THE UNIVERSITY OF MADRAS LECTURER IN OPHTHALMOLOGY, LONDON SCHOOL OF TROPICAL MEDICINE OPHTHALMIC SURGEON TO THE SEAMEN'S HOSPITAL SOCIETY, AND TO THE HOSPITAL FOR TROPICAL DISEASES, ENDSLEIGH GARDENS, LONDON WITH 213 ILLUSTRATIONS AND FRONTISPIECE LONDON HENRY FROWDE AND HODDER & STOUGHTON THE LANCET BUILDING i BEDFORD STREET, STRAND, W.C. 2 First Edition . . . 1918 Second Edition . 1922 l-KIXTKIi IN OREAT BRITAIN BY MORRISON AND OIBB LTD., EDINBURGH Go E. C. I. E. PREFACE TO THE SECOND EDITION I MUST commence with an apology for the long delay in bringing out a second edition. It has been due to the fact that I am obliged to do my literary work in my spare time, and that the amount of labour involved in following up the many additions to the literature of Glaucoma during the past four years has been very great. I have altered the title, for I have given my book a more ambitious scope than before. I have felt it was more than a textbook that was wanted. There are so many questions in connection with glaucoma which are still unanswered, and there is still so very much work to be done, that I have felt that the aim to be kept before me was the writing of a book which would enable a reader to recognise the stage to which any part of the subject has been brought by the work of those who have preceded him. It is my hope that, in this way, I shall be able to be of assistance to those who desire to advance our know- ledge by a further study of the many problems still await- ing solution, and thus shall, even in some small measure, succeed in stimulating research. I am convinced that the man or the profession, that rests content with the knowledge bequeathed by the past, is bound to move backwards instead of forwards. The opportunities for research in connection with glaucoma are immense, and I would commend this subject to all who have the privilege to be teachers in medical schools. It is for them to inspire their students and to direct their energies along such lines. Then again I have had a second object before me : vii viii PREFACE TO THE SECOND EDITION Often and often in the treatment of patients suffering from glaucoma, questions have arisen in my mind to which I could find no answer. It has accordingly been my endeav- our to marshal the knowledge at our disposal in orderly array, so that any point of doubt or difficulty can be de- cided, if possible, for the inquirer by a reference to the work that has been done in the past, much of which has lain hidden in works which are very inaccessible to most of us. A third object has been kept before me, and one which many would have expected me to have placed first : I have sought to give a full, clear, and consecutive account of my subject, so that those who desire to master it as a whole may be able to do so by a perusal of my pages. In this sense the work is a textbook, but, as I have explained under my two previous headings, in a wider sense it is much more. I have striven consistently to give credit where credit is due, and to put forward the views of others as freely and as fully as my own, even when I differ from them. There must always arise in such a work as this, questions of precedence and differences of opinion as between different surgeons. My rule has been to state the facts, quoting verbatim as far as possible from the authors themselves, and to leave the inferences to the reader. A feature of this edition has been that the references are placed at the end of each Part of each Chapter, and that they have been made so full that anyone who works from them, as a starting-point, can easily obtain access to the whole literature of the subject. An effort has been made to bring each section of the book thoroughly up to date. Fresh papers have been included even while the proofs have been in the Press right up to January 1922. Considerable additions have been made, and parts of the book have been practically PREFACE TO THE SECOND EDITION ix rewritten. It is possible that, despite every effort to the contrary, important papers have been overlooked ; if this has been the case, I shall sincerely regret it. The literature has been so enormous that no one can feel confident that omissions have not occurred. The number of illustrations has been raised from 158 to 213 and Frontispiece, though even this does not indicate the true increase, since a number of the old figures have on several occasions been included under one number instead of under two or three. It remains for me to make acknowledgment of the great help I have received from my many correspondents all over the world. I appreciate their suggestions and the many kind things they have written more than I can tell them. I have also to express my indebtedness to those who have helped me by the specific acts of kindness enumerated below : The American Journal of Ophthalmology permitted me to reproduce the illustration found in Fig. 53. Professor Bailliart supplied the block of his ophthalmo- dynamometer (Fig. Ill), and sent me kind personal com- munications. The British Journal of Ophthalmology gave me per- mission to copy the illustrations appearing as Figs. 6, 159, and 160. Dr. Gradle furnished the block of Fig. 106. Dr. McLean furnished the block of Fig. 107. Messrs. Zeiss furnished the blocks of Figs. 29, 45, 113, and 114. Professor Morax furnished the blocks of Figs. 24-27, 40-43, 104, 108, and 109. Dr. Luther C. Peter and the Editor of the Archives of Ophthalmology gave me permission to copy the illustration which appears as Fig. 50. Professor Schiotz furnished me with the photograph for Fig. 105s. x PREFACE TO THE SECOND EDITION Mr. Edgar Stevenson furnished me with the photo- graph reproduced as Fig. 117. Mr. A. Hugh Thomson permitted me to make use of the illustration reproduced as Fig. 44. The Council of the Ophthalmological Society of the United Kingdom supplied the blocks of Figs. 44, 86-93, and 203-210. Messrs. Weiss supplied the blocks of Figs. 72, 73, 110, 157s, and 184. I have kept two acknowledgments to the end. I should be remiss indeed if I were not grateful to my Publishers for their invaluable help in all matters connected with the production of the book, which has always been freely and generously placed at my service. Lastly, Mrs. Elliot has helped me from start to finish, not only with photo- graphs and drawings, but in every possible way. Without her assistance I could not have brought out this second edition, and should not have attempted to do so. ROBERT HENRY ELLIOT. 54 WELBECK STREET, LONDON, W. 1, 23rd January 1922. PREFACE TO THE FIRST EDITION IT has been my ambition for many years, to write a book on Glaucoma, which might be helpful to other students of the subject. It was only when I began to study care- fully and systematically the vast literature available, that I realised how great the task really was, and how chaotic were many of the prevailing views. I found that much had been taken for granted without sufficient evidence ; that incorrect data had been confidently built upon ; that the same terms had been used in different senses by different writers, and that many other sources of confusion had been introduced. For three years I have patiently and steadily striven to unravel the tangle, to separate the true from the false, to learn the views of those who are best qualified to speak, to weigh their opinions against each other, and to strive to winnow out the wheat from the chaff. In doing so, I have been amazed at our ignorance of many important points ; I have striven to give everyone a fair hearing, to eliminate all prejudice from my judgments, to give full credit where it is due, but unhesitatingly to reject anything and everything which appears to me unworthy of credence, be the authority for it what it may. In doing so, it has been my earnest endeavour to avoid giving offence. I repeat that it is my desire to help the honest student, and in striving to do so, I have certainly helped myself to a clearer comprehension of this great subject. It has been my aim and object to state each case as clearly and as simply as possible, while at the same time, putting my facts forward in as readable a manner as I could. xii PREFACE TO THE FIRST EDITION The experience of years has left me as fully convinced of the value of sclero-corneal trephining as when I penned the first edition of my monograph on that subject (" Sclero- corneal Trephining in the Operative Treatment of Glau- coma," George Pulman & Sons Ltd. First Edition, 1913 ; Second Edition, 1914). In the present volume, however, I have endeavoured to take a much wider view and to present not only my own individual ideas, but those also of all surgeons, who have left any mark behind them. I have studiously refrained from burdening the reader with statistics. Those who are interested in such figures will find them given at length in the second edition of " Sclero-corneal Trephining " and in my summaries of the year's work on Glaucoma in the Ophthalmic Year Books of 1913 to 1916. A perusal of these articles will show how vast the subject is. I have endeavoured to acknowledge the sources of the valuable help I have received in the pages of the book, but there are certain special matters that I desire to mention. The editors of The Ophthalmoscope, The Ophthalmic Review, and The Ophthalmic Record have courteously per- mitted me to reproduce as chapters of this volume the articles which have appeared in their pages. Those articles have been extensively rewritten to bring them up to date, and for that purpose the current literature has been care- fully surveyed, inclusive of that for the year 1917. The Council of the Ophthalmological Society and the Editorial Committee of the British Journal of Ophthal- mology have kindly permitted me to reproduce certain illustrations from their Transactions and Journal. My book has been enriched by the kindness of Mr. Priestley Smith, who with his usual generosity, has allowed me to make use of a number of his classic illustrations. To Mr. Treacher Collins I am indebted, not only for the PREFACE TO THE FIRST EDITION xiii loan of many beautiful specimens, but also for the oppor- tunity to discuss with him some of the difficulties with which I have been confronted in the course of my study of the subject. To Professor Bjerrum, Professor Roenne, and Dr. Sinclair my thanks are due for the generous way in which they placed their perimetric material at my disposal. I am much indebted to Mr. Adams Frost and to Messrs. Henry Frowde and Hodder & Stoughton for very gener- ously allowing me to reproduce as my frontispiece the well-known coloured illustrations of the glaucoma cup, which appear in the " Adams Frost Atlas of Ophthal- mology." I deeply appreciate their liberality in doing so. Professor Arthur Thomson has likewise most gener- ously allowed me to make use of the very beautiful illus- trations which appeared in his articles in The Ophthal- moscope. Messrs. Weiss and Messrs. George Spiller have very kindly furnished me with blocks which they were good enough to prepare for the purpose. A number of the illustrations are from original photo- graphs by Mrs. Elliot, to whom I am also indebted for much help in the proof-reading and in other ways. The difficulties of bringing out the book in war time have been very great, and I therefore feel that I must express my indebtedness to Mr. H. L. Jackson of Messrs. H. K. Lewis & Co. Ltd. for the valuable assistance he has given me. ROBERT HENRY ELLIOT. 54 WELBECK STREET, CAVENDISH SQUARE, LONDON W., 1918. CONTENTS I. PRELIMINARY ....... 1 PART I. Introductory . . . . .1 PART II. The Anatomy of the Parts concerned in Glaucoma 3 PART III. Historical . . . . . .18 II. THE INTRA-OCULAR PRESSURE AND THE TENSION OF THE EYE 23 PART I. The Terms used . . . . .24 The Physical Conditions regulating the Intra- Ocular Pressure . . . . .27 PART II. The Bearing on Intra-Ocular Pressure of the Continuous Flow of Fluid through the Chambers of the Eye . . . .40 The Changes in the Chamber Pressure which attend Some Forms of Glaucoma . . .45 The Source and Method of Production of the Intra-Ocular Fluid . . . .49 Magitot's Views . . . . .55 PART III. The Relationship of Systemic Blood-Pressure to Intra-Ocular Pressure . . .59 The Relationship between the Intra - Ocular Blood-Pressure and the Intra-Ocular Fluid Pressure Outside the Vessels . . .64 III. THE ^ETIOLOGY OF GLAUCOMA . . . . .83 PART I. Introduction . . . . .84 PART II. The Pathological Anatomy of Glaucoma . 87 PART III. The Pathological Anatomy of Glaucoma (continued) . . . . .102 PART IV. The Causes of Glaucoma . . . .121 IV. THE DIAGNOSIS OF GLAUCOMA ..... 149 PART I. Introductory ..... 149 The Stages of Glaucoma .... 152 The Clinical Course of a Simple Attack . 155 The Clinical Course of a Congestive Attack . 159 PART II. The Signs and Symptoms of Glaucoma, con- sidered from an Anatomical Point of View . 166 PART III. Subjective Phenomena .... 224 xvi CONTENTS CHAPTER PAGE PART IV. The Visual Field ... 228 PART V. The Visual Field (continued) . . . 294 PART VI. Tonometry ..... 317 The Examination of the Light Sense . . 338 V. SECONDARY GLAUCOMA ..... 346 PART I. Introductory ..... 347 PART II. ^Etiology . . . 347 PART III. Treatment . . .... . 385 VI. CONGENITAL GLAUCOMA AND SOME ALLIED CONDITIONS . 400 VII. THE MEDICAL TREATMENT OF GLAUCOMA ; . . 442 VIII. IRIDECTOMY IN GLAUCOMA . . . . 458 PART I. The Opinions of the Old Masters . . 458 PART II. The Views of Modern Surgeons . . 473 PART III. The Technique of the Operation of Ii idectomy for Glaucoma .... 483 IX. THE NEWER OPERATIONS FOR GLAUCOMA . . . 487 PART I. The History of the Newer Operations for Glaucoma . , . . . 488 PART II. Preparations for Operation . . . 504 PART III. Sclerotomy for Glaucoma . . . 510 PART IV. Lagrange's Operation . . . 511 PART V. Hoi th's Operation .. . .515 PART VI. Herbert's Operations .... 522 PART VII. Scleral Trephining (Fergus's Operation) . 526 PART VIII. Sclero-Corneal Trephining (Elliot's Opera- tion) ..... 531 PART IX. Modifications of Sclero-Corneal Trephining suggested by Various Surgeons . . 559 PART X. Complications which may be met with dur- ing a Glaucoma Operation . . 571 PART XI. After-Management of Patients operated on for Glaucoma .... 578 X. THE PATHOLOGY OF FILTRATION . . . . 603 PART I. The Filtering Scar in the Treatment of Glaucoma . . . . .603 PART II. The Histology of the Trephined Disc in Glaucoma Operations . . .618 APPENDIX A New Instrument for measuring the Diameter of the Cornea . . . . . .639 INDEX OF NAMES . . 641 INDE& OF SUBJECTS . * , . G46 LIST OF ILLUSTRATIONS Glaucomatous Cupping of Optic Disc . . . Frontispiece 10. PAGE 1. Meridional Section through the Anterior Portion of the Eye . 4 2. Showing the Blood Supply of the Ciliary Body and of the Adjoining Parts ..... facing 5 3. Canal of Schlemm reconstructed . . . . . . .6 4. Ditto . . ... . . . .7 5. Optic Nerve Entrance . . . . . .13 6. Canal of Entrance of Optic Nerve . . . .13 7. Lamina Cribrosa . . . . . . .15 8. Ditto ........ 15 9. Ditto ....... 16 10. Manometer for Estimation of Intra-Ocular Pressure . . 25 11. The Filtration Angle ...... 74 12. Diagram showing Pump Action on Canal of Schlemm . . 75 13. Section through Pectinate Ligament . . . .78 14. Diagram showing Valvular Action of Channels in Pectinate Ligament . . . . . . .79 15. Mechanical Closure of Filtration Angle in Acute Glaucoma . 103 16. The Angle of Chamber opened and closed . . . 104 17. Filtration Angle closed by Adhesion : Acute Glaucoma . . 105 18. Compression of Iris Stroma ..... 107 19. Iris atrophied, and Ciliary Processes retracted . . . 107 20. Section of Normal Eye . . . . . .109 21. Section of Glaucomatous Eye ..... 109 22. Blocking of Pectinate Ligament by Cells . . .114 23. Shallowing of Angle of Chamber preceding Glaucoma . . 114 24. (Edema of Cornea in Acute Glaucoma .... 169 25. Ditto ........ 170 26. Corona of Light round a Flame . . . . .176 27. Druault's Experiment . . . . - .179 28. Ditto ........ ISO 29. Ulbrich's Drum 188 xviii LIST OF ILLUSTRATIONS FIG. PAGE 30. Ectropion Uveoe ....... 190 31. Section of Glaucomatous Cup . . . . . 197 32. Paper Device to illustrate Points in Connection with Glau- comatous Cupping ..... facing 203 33 Ditto . ..... do. 203 34. Ditto . . . . . . . do. 203 35. Ditto . . . . . . . do. 203 36. Diagram of Glaucoma Cup . . . .do. 208 37. Diagram of Physiological Cup . . . .do. 208 38. Diagram of Atrophic Cup . . . .do. 208 39. Coloboma of the Optic Nerve . . . .do. 208 40. Glaucomatous Cup ...... 209 41. Ditto ........ 210 42. Coloboma of the Optic Nerve ..... 211 43. Coloboma of Sheath of Optic Nerve .... 212 44. Large Intra-marginal Cup . . . . . 215 45. Corneal Microscope and Slit-lamp .... 220 46. Normal Visual Fields (Sinclair) ..... 230 47. Normal Visual Fields (Bjerrum) .... 230 48. Papillo-Macular Bundle in Cross Section of Optic Nerve . 233 49. Distribution of Nerve Fibres on Retina (Baas) . . . 234 50. Distribution of Nerve Fibres on Retina (Peter) . . . 236 51. Ditto . . . . . . . .237 52. Ditto, enlarged ....... 238 53. The Fund us by Red-free Light . . . . .239 54A. Early Shrinkage of Nasal Field . . . . .241 54B. Later Stage of above ...... 241 55. Field in Late Chronic Glaucoma ..... 243 56. Ditto ........ 243 57. Visual Field, Left Eye : Late Chronic Glaucoma . . 244 58. Ditto, Right Eye . . . . . . .244 59. A Sectored Field : Chronic Glaucoma .... 245 60. Remnant of Visual Field : Late Chronic Glaucoma . . 245 61. Defects in Nerve Bundles corresponding to Field Defects of Next Figure . . . . . . .246 62. Bjerrum's Sign and Roenne's Step .... 247 63. Colour Fields in Chronic Glaucoma .... 248 64. Fields showing Bjerrum's Scotomata (Sinclair) . . . 250 65. Ditto . . . . . . . -251 66. Ditto 252 LIST OF ILLUSTRATIONS xix FlG. PAGE 67. Fields showing Signs of Optic Atrophy (Sinclair) . . 252 68. Bjerruin's Screen on Stand ..... 253 69. Bjerrum's Screen on Spring Roller .... 254 70. Marks' Recording Scotometer . . . . 255 71. Author's Scotometer ...... 258 72. Author's Head-rest . . . . . .259 73. Author's Pointer . . . . . . .259 74. Form for recording Scotometer Readings . . . 260 75. Scotometer Chart, Blank ..... 261 76. Normal Blind Spots charted ..... 262 77. Scotometer for Use with Bjerrum's Screen . . . 263 78. Author's Large Perimeter ..... 264 79. Bjerrum's Scotoma (absolute) ..... 265 80. Bjerrum's Double Arcuate Scotoma .... 265 81. Roenne's Glaucoma Fields ..... 266 82. Ditto . . . . . . . .269 83. SeidePsSign . . . . . . .271 84. An Early Scotoma charted by Means of the Author's Scoto- meter ........ 273 85. The Same Field Ten Days after Operation . . .273 86. Author's Scotometer Chart ..... 275 87. Ditto . . . . . . . .276 88. Ditto ........ 277 89. Ditto ........ 278 90. Ditto ........ 279 91. Ditto ........ 280 92. Ditto . . . . . . . .281 93. Ditto ........ 282 94. Paracentral Scotomata separated from Blind Spot . . 288 95. Charts showing Progress of Central Scotomata (Van der Hoeve) ........ 289 96. Ring Scotoma (Van der Hoeve) . . . . .291 97. Hemianopic Field : Chronic Glaucoma (Bjerrum) . . 291 98. Central Relative Scotoma (Bjerrum) . . . .292 99. Bow-shaped Remnant of Field (Bjerrum) . . . 292 100. Quadrantic Defect of Field (Bjerrum) . . . .293 101. Anatomical Distribution of the Nerve Fibres in the Retina . 302 102. Field of Vision . . . . . . .308 103. Schematic Section of Eye .... 309 104. The Principle of the Schiotz Tonometer . . . 319 xx LIST OF ILLUSTRATIONS KIO. PAOB 105A. Scliiotz Tonometer (Original Model) . . . . 320 105B. Ditto (New Model) . . ... . .321 106. Gradle's Tonometer . ' . : . .322 107. The McLean Tonometer . . . 322 108. Application of the Schiotz Tonometer .... 330 109. Ditto ........ 331 1 10. Tonometric Chart ...... 336 111. Bailliart's Ophthalmo-dynamometer ..: ; . . . 337 112. Author's Light Sense Apparatus . . . . 341 113. Zeiss' Photometer . . ..: . . .343 114. Ditto (in Section) ...... 344 115. Wound of Cornea : Secondary Glaucoma . . . 349 116. Perforating Ulcer of Cornea : Secondary Glaucoma . . 350 117. Staphyloma of Cornea . .;>... . . . 351 118. Ditto ........ 352 119. Fistula of Cornea . . .353 120. Ditto, Higher Magnification ..... 353 121. Annular Posterior Synechia . . . . 354 122. Diris bombd . ... . . . . 355 123. L'iris bombtf . . . . . . .355 124. Anterior Dislocation of Lens ..... 356 125. Nucleus of Cataract, freely movable between Chambers . 356 126. Anterior Dislocation of Lens ..... 357 127. Lens Nucleus impacted in Angle of Anterior Chamber . 358 128. Lateral Dislocation of Lens ... . . . 359 129. Ditto, Higher Magnification . , . . .360 130. Posterior Dislocation of Lens . . . . . . .361 131. Reclined Cataract . . . . . .361 132. Blocking of Angle of Chamber by New Formation . . 362 133. Epithelial Cyst of Anterior Chamber . . . .369 134. Ditto, Higher Magnification - . . . . .369 135. Downgrowth of Epithelium along Track of Wound . .371 136. Capsulo-Corneal Synechia . . . . .371 137. Tumour of Iris and Ciliary Body .... 376 138. Tumour, of Iris . . .377 139. Sarcoma of Choroid ... . 378 140. Vitreous Streamers . . . 392 141. Buphthalmic Child . . . .404 142. Section of Buphthalmic Eye ... .405 143. Ruptures of Descemet's Membrane .... 406 LIST OF ILLUSTRATIONS xxi FIO. I'AiiK 144. Ruptured of Descemet's Membrane, in Section . . . 417 145. Fcetal Condition of Angle of Chamber . . : . . ... 419 146. Iridectomy for Glaucoma . . . -. . 485 147. Madras Eye Bandage . . . 509 148. De Wecker's Sclerotomy . . , . . . : . 510 149. Lagrange's Operation . ... . .512 150. Ditto . . . . .512 151. Ditto ... . 513 152. Ditto ... .... 513 153. HoltVs Forceps . . . . . . .516 154. Hoi tb's Keratome . . .516 155. Holth's Double Hook . ... 516 156. Holth's Iris Forceps . .516 157A. Holth's Punch-Forceps . . . . . . 517 157s. Ditto (New Model) . . . . . . . 517 158A. Diagram of Holth's Operation . . . . . .517 158B. Ditto ...... .517 158c. Ditto .... . .517 159. Diagram of Holth's New Operation .... 520 160. Section of Eye to show Holth's New Operation . . 521 161. Herbert's Wedge-Isolation Operation ... . . 523 162. Ditto . . . .... . .523 163. Herbert's Small Flap Operation . .... 524 164. Ditto . . . . . . . .524 165. Ditto ... . . .524 166. Herbert's Triple Small Flap Operation . ... . 525 167. Ditto . . . . - . . . . . . .525 168. Ditto . . . . .... .525 169. Early Incision in Sclero-Corneal Trephining . . . 533 170. Present Incision in Sclero-Corneal Trephining . . 533 171. The Flap in Sclero-Corneal Trephining . . . 535 11-2. Disc Forceps for Trephining ... . 546 173. Diagram of Parts concerned in Trephining . . . 553 174. Ditto ........ 554 175. Ditto ...... .555 176. Ditto . . . . . . . .556 177. Bowman's Trephine ... . 560 178 Stephenson's Trephine ... . 560 179. Author's Trephine . . . . . .560 180. Gray Clegg's Slotted Trephine Blade . . . .561 XX11 LIST OF ILLUSTRATIONS FIQ. PAGE 181. Lang's Trephine . . . . . . .561 182. Pusey's Trephine . . . . .561 183. Butler's Trephine . . . . . .561 184. Young's Trephine ...... 562 185. Von Hippel's Trephine . . . . . .562 186. Vogt's Motor Trephine . . . . .563 187. Taylor's Motor Trephine . . . . .563 188. Desmarres' Knife used in Splitting the Cornea . . 564 189. Lang's Knife for Splitting the Cornea .... 564 190. Stephenson's Knife for Splitting the Cornea . . . 564 191. McEeynold's Corneal Wedge ..... 564 192. Von Mende's Flap ..... 565 193. Dupuy-Dutemps' Flap ...... 565 194. Hill Griffith's Flap .... . 566 195. Photo of Filtering Scar during Life .... 568 196. Ditto ........ 569 197. Method of Fixation of Eye by Traction of Thread . . 572 198. Filtering Scar after Removal of Eyeball . . . 606 199. Filtering Scar in Section ..... 607 200. Ditto ........ 608 201. Ditto . . . . . . . .609 202. Ditto . . . . . . . .610 203. Ditto ........ 620 204. Trephined Disc in Section . . . . 623 205. Ditto ........ 624 206. Ditto ........ 625 207. Ditto . . . . . . . .626 208 Ditto ........ 628' 209. The Splitting up of Descemet's Membrane . . . 630 210. Excrescences on Descemet's Membrane .... 631 211. Ditto, under Higher Magnification .... 632 212. The Splitting up of Descemet's Membrane . . . 635 213. The Author's Microscope for the Measurement of the Cornea . 639 A TREATISE ON GLAUCOMA CHAPTER I PRELIMINARY SUMMARY PART I INTRODUCTORY. PART II THE ANATOMY OF THE PARTS CONCERNED. PART III HISTORICAL. PART I Introductory THE term " glaucoma " is not the title of any one single disease. It is rather a convenient clinical label for a large group of pathologic conditions, the distinctive feature common to all of which is a rise in the intra-ocular pressure. The causes of these conditions are many and varied, the pathological findings are most diverse, and the differ- ence in the symptoms presented is so extraordinary, that very careful study is required to detect the bond which serves to unite these very dissimilar manifestations of disease in a common category. When we speak of the hardness of a glaucomatous eye, or of its rise in tension, we are referring to the outward \ 2 GLAUCOMA manifestations of an increase of the fluid pressure within the globe. To this increase all the causes of glaucoma lead up ; on it every sign and symptom of the condition depend. If the rise in pressure can be traced to the action of some antecedent local disease, we speak of the glaucomatous condition as secondary ; failing this we term it primary. The presence of an increase in intra-ocular pressure necessarily brings about some measure of interference with the free escape of blood from the interior of the eye to the surface. So long, however, as such interference does not give rise to obvious congestion of the eye or of its con- junctiva, we speak of the condition as " simple or non- congestive glaucoma." When evidence of interference with the venous return makes its appearance, the disease is said to be " congestive." The term " inflammatory," though often used in this connection, is erroneous and should be dropped. The classification of all cases of glaucoma into three groups viz., the acute, the subacute, and the chronic has been productive of much confusion, owing to the difference in the way in which these terms have been used by writers on the subject. Those cases which present the signs and symptoms of severe congestion, as a result of a steep rise in intra-ocular pressure, may reasonably be spoken of as acute, the term subacute being reserved for those in which the evidence of congestion is less pronounced. To define a chronic case is more difficult. All that the term really implies is that the condition has lasted for some time ; but, in accepted usage, it is also understood that the case is not in an acute or subacute stage. Any glaucoma- tous eyeball, whether of the simple or of the congestive type, may fall into this category. The point to be emphasised is that there is no such thing as acute, sub- acute, and chronic glaucoma. Any glaucomatous eye may be in an acute, a subacute, or a chronic stage, and may readily pass from one to another of these stages, and back again into that from which it sprang ; but to speak of PRELIMINARY 3 acute, subacute, and chronic glaucoma, as if we were deal- ing with so many clinical entities, is wrong and misleading. PART II The Anatomy of the Parts concerned in Glaucoma Before we can study the processes of disease in an organ, or the methods of combating them, it is essential that we should make ourselves acquainted with certain anatomical details of the structures concerned. The ciliary body and the parts adjoining it are " the cock- pit " of glaucoma. A study of Figs. 1 and 1 1 (v. pp. 4 and 74) will make a number of important points clear ; a few of the more essential anatomical features demand some attention. The Conjunctiva. It will be noted in the illustration (Fig. 1) that the subconjunctival tissue is continued well in advance of the sclero-corneal junction. It is along this layer that we work in " splitting the cornea " in the oper- ation of trephining, and the looseness of the tissue just referred to explains the ease with which that manoeuvre is conducted. Schlemm's Canal (Figs. 1 to 4 and 11) lies at the junction of the cornea and sclera, close to the inner surface of the corneo-scleral envelope. It is separated from the aqueous chamber only by the loose open network of the pectinate ligament (Figs. 1 and 11). Fluid can pass readily from the chamber to the canal through the open spaces of this meshwork, but there is no direct connection between the canal and the chamber. The anatomy of these parts has recently been very carefully worked out by Maggiore, and some points of special interest deserve a reference here. He has reconstructed a schematic section of the area (Fig. 2) from a large number of serial sections, in order to show the connections of the various vascular plexuses of this important neighbourhood. This figure is worthy of the careful study of all who are interested in the ana- tomy of glaucoma. FIG. 2. Reconstruction of a schematic section, showing the blood supply of the ciliary body and the parts adjoining it. The connection of the various vascular plexuses is shown. L, limbus ; C, conjunctival plexus of vessels ; T, plexus of vessels in Tenon's capsule ; PL.e, episcleral plexus : PLi, intrascleral plexus ; C.Sch, canal of Schlemm, with small collector vein, c ; Ac.a, anterior ciliary artery ; VCa, anterior ciliary vein ; Me, plexus in ciliary muscle ; VMc, vessels of the ciliary muscle ; PrC, ciliary processes ; Sc, sclera. PRELIMINARY 5 In addition, he has made a plaster reconstruction of the canal of Schlemm, and photographs of parts of this are shown in Figs. 3 and 4, which are as interesting as they are instructive. He finds that the canal has a complete endothelial lining. Under normal conditions, it contains clear lymph only, and no blood corpuscles ; but it is evidently a vas- cular structure, and it is joined to the deep pericorneal vascular plexus by 20 to 30 connecting trunks, which have a very small lumen, and only appear as slits. This deep plexus (Fig. 2, PLi) is formed of numerous veins with a few slender and scanty arterial twigs. As is well known, it plays a leading part in glaucoma. Maggiore's pathological studies of this area are also interesting, as tending to show that blood corpuscles and inflammatory cells have a strong tendency to work their way from the angle of the anterior chamber, through the spaces of the pectinate ligament, into Schlemm's canal. Similar observations have been made by earlier investigators, especially in connection with free cells detached from malignant growths of those parts of the uveal tract, which abut on the aqueous chamber. The inference from this evidence favours the hypothesis of the outflow of fluid at the angle of the anterior chamber. The point is of interest as the very existence of a drainage flow by way of the angle of the anterior chamber, has recently been challenged. It is difficult to take such a challenge very seriously. The Scleral Spur (Figs. 1 and 11) lies between the pectinate ligament anteriorly and some fibres of the ciliary muscle posteriorly. A contraction of these fibres will pull back the spur and tend to open wide the canal of Schlemm. As soon as muscular contraction ceases, the pectinate ligament, being elastic, will draw the scleral spur back into place, and so close the canal of Schlemm (Arthur Thomson). It will be shown later (Chapter II. Part III.) how this pump action, by its constant repetition during the waking hours, draws the fluid from the anterior chamber into the canal of Schlemm, and then sweeps it on again from the canal into the neighbouring veins. a o " 'C -2 , 3 5 s * , n > 1 1 * s * O (<-i "- 1 m O B feD o I -S & -2 fe a B .S > a II 3 _S o % 05 a 0, - 8 GLAUCOMA The Anterior Chamber has an almost exactly circular contour, while the cornea is oval in shape with its long axis transverse ; the consequence is that the extent of the angle of the chamber concealed by the scleral border varies considerably in different directions. Rochon-Duvigneaud worked this matter out with great care and gave the follow- ing measurements of the interval between the transparent edge of the cornea on the one hand, and the angle of the anterior chamber on the other : (1) above the cornea in the vertical axis, 2' 25 mm. ; (2) below the cornea in the same axis, 2 mm. ; (3) to the nasal or temporal side of the cornea in the horizontal axis, I' 25 mm. These measure- ments naturally vary in individual eyes, and the author's researches showed that in the smaller and lighter Indian patient they are slightly less than those obtained on European subjects by the French worker. The importance of a knowledge of these facts to the surgeon, who has to consider the various operations for glaucoma, is too obvious to need emphasis. The Angle of the Chamber (Figs. 1 and 11) is at the best of times a narrow space. Inasmuch as the outflow of the aqueous fluid takes place in this neighbourhood, it is most important that the angle should remain widely open. Its patency may be infringed in several ways : 1. Extreme dilatation of the pupil, by crowding the membrane out to its periphery, tends to fill up the angle, and so to impede the passage of fluid through it. 2. The ciliary body may become swollen by congestion with blood. If it does so, its apices move forward. A glance at the illustration (Fig. 1) will show that, if this happens, these apices will press upon the base of the iris, and push the latter forward against the cornea, thus closing the angle. A second point may be learnt from this drawing : If the apices of the ciliary body move forward, the attachments of the suspensory ligament of the lens do the same ; this, obviously, will allow the lens to advance, and so to press on the base of the iris. In this connection Figs. 21 and 23 may be profitably consulted now. 3. As life advances, the lens enlarges, whilst the tunic PRELIMINARY 9 of the eye remains stationary in size. The swollen lens tends to press the iris forward, and so to occlude the angle, just as in the previous case. 4. When the iris and cornea are brought into close apposition, in one of the ways above described, their adjacent surfaces are apt to be glued together by the exudate they throw out. In this way a permanent oblitera- tion of the angle may be brought about. The Iris. On the anterior surface of this membrane are found pit-like depressions, the crypts of the iris (Fig. 1), which lead to the depth of the iris stroma, and which place its tissue spaces in free communication with the cavity of the aqueous chamber. In this stroma the fluid comes into intimate contact with the thin-walled iris veins, and passes into the latter, probably by osmotic action. The crypts are of importance when the angle of the chamber is in an early stage of closure, for the fluid from the chamber can enter through them and find its way along the iris stroma to the neighbourhood of the pectinate ligament, across which it then passes to enter Schlemm's canal. The Ciliary Body. Whilst few authorities now accept the suggestion that there are definite tubular secretory glands in this body, it is believed that its lining cells have the power of taking up fluid transuded into their neighbourhood from the capillary vessels, and passing it across on to the free surface by a definite act of secretion. The view usually accepted is that the fluid thus poured out passes by two streams, one backward into the vitreous, and the other inward and forward into the posterior divi- sion of the aqueous chamber ; thence it finds its way through the pupil into the anterior division of that chamber, and flows outward all round to reach the angle. The ciliary body presents a large surface of attachment to the sclera. This is of interest in connection with the operation of cyclodialysis, the purpose of which is to tear the former structure away from the latter over the area marked out by a limited incision ; the pectinate ligament is obviously divided during this step. The object aimed at is to open up a communication between the anterior 10 GLAUCOMA chamber in front and the suprachoroidal space behind, by means of the detachment of the ciliary body. The vessels and nerves which supply the ciliary body and iris pass forward between the choroid and the solera. In this course they are exposed to the full force of the intra-ocular pressure, since they lie against the hard un- yielding scleral coat. There is a free communication between the vascular system in the interior of the eye and that on its surface through the perforating vessels, which pierce the sclera close behind the cornea. Morax has discussed the nature of these anterior ciliary vessels which are so constantly found dilated in subacute glaucoma. He appears to lean to Heerfordt's view that these are arterial and not venous, but he has had some difficulty in making up his mind on the subject. The author has devoted some attention to these vessels, and is strongly inclined to believe that they are venous and not arterial for the following reasons : (1) If a length of the vessel is rendered bloodless and pressed on with spatulae at two distant points, it fills quite as readily, if not more readily, from the direction of the eyeball than from the opposite one. (2) When one of these vessels is cut during an operation, the bleeding from it is never pulsatile. (3) When quite a large trunk of this kind is examined under very high magnifications, with a corneal microscope, not the faintest trace of pulsation can be detected. The whole of the choroidal and retinal circulation lies between the fluid contents of the eye and the unyielding sclera, and must suffer whenever the pressure within the eye is increased. The arterial and venous circulations react differently. The pressure diminishes the amount of blood entering the eye through the arteries, and also that leaving it through the veins. The effect is to dimin- ish the arterial supply and to establish a condition of venous congestion. If the pressure rises slowly, the circulation can adapt itself to the change of conditions, and the glaucoma remains simple. If, on the other hand, the increase in pressure is a rapid one, no such adapta- PRELIMINARY 11 tion is possible, and an attack of congestive glaucoma is the result. This, however, is possibly far from being the whole truth. It seems probable that the anatomical conditions, governing the escape of the venous blood from the eye, and those of the reservoirs into which this blood is passed immediately after its exit, exercise a profound influence on the incidence of the vascular factor when high tension supervenes. To this point we shall return on a later occasion. It is important to bear in mind that there are two quite separate and independent vascular systems within the eye. Of these, one cares for the retina and the retrobulbar seg- ment of the optic nerve, whilst the other is responsible for the uveal tract, the solera, and some part of the episcleral tissue. The most important channels for the uveal tract are the posterior ciliary arteries, which are about 20 in number. The long posterior and the anterior ciliary arteries contribute more modestly to the arterial supply. The veins are two or three times more numerous than the arteries, and are of much larger calibre. They arise sud- denly from the fusion of about fifteen capillaries which meet in a small vortex, and in turn form larger vortices, called " venae vorticosse." The anterior segment of the eye is also rich in veins ; this is especially true of the ciliary region, the ciliary processes being almost entirely made up of bunches of veins. In spite of the seemingly large number of anastomoses between the anterior and posterior venous systems, the suppression of either leads to a marked venous stasis of the eye (Magi tot). The fluids of the eye are of three kinds : (1) The blood, (2) the lymph, and (3) the aqueous humour. The aqueous humour differs from the other two in containing very little albumin and a high percentage of sodium chloride, whilst they contain much albumin and less salt. This matter will be dealt with at more length when we are discussing Magitot's views on the origin of the aqueous humour. The Entrance Canal of the Optic Nerve. The scleral coat is perforated for the passage of the second cranial nerve into the globe. The hole is, however, not clean punched out, 12 GLAUCOMA but is partially blocked by a fibrous membrane, the lamina cribrosa, which, as we shall presently see, is a thinned out portion of the scleral tissue. It has neither the thickness, measured antero-posteriorly, nor the density of the scleral coat ; in addition to this, it is perforated by a number of apertures for the transmission of the bundles of fibres of the optic nerve. It is not strange therefore that this should prove the weakest part of the wall of the eye, and consequently that which is the first to yield under a rise of intra-ocular pressure. If the neighbourhood of the ciliary body may be described as the " cookpit " of glau- coma, this area equally merits the title of the " graveyard " of that disease, for it is here that there lie hid the dead and wasted nerve-heads, killed by the fatal intra-ocular pres- sure. The canal is divided for anatomical purposes into a choroidal and a scleral portion. The inner or choroidal opening of the canal is about 1'5 mm. in width ; it may be taken to be bounded by the margin of the opening in the choroid, and by the contiguous part of the solera. The outer opening, or scleral foramen, as is well known, is usually much wider than the inner ; its boundary is formed by the outermost layers of the sclera. An antero-posterior section through this part of the eye shows the optic nerve and its canal presenting roughly the appearance of a truncated cone with its base external, and its truncated end internal (Fig. 5). The explanation of this lies in the fact that the fibres of the optic nerve lose their medullary sheaths as they pass through the scleral coat of the eye ; at the same time, the coarse intraneural septa disappear ; the bulk of the nerve consequently diminishes considerably from without inward. From such considerations it is easy to understand the shape of the advanced glaucoma cup with its overhanging edges and with the apparent inter- ruption in the continuity of the blood vessels which emerge from it, as seen by the ophthalmoscope. A reference to Fig. 31 and to the Frontispiece will make these points additionally clear. The wall of the canal is formed by a whitish fibrous PRELIMINARY 13 tissue, which, in the choroidal part of the tube, is clearly distinguishable from the uveal layers, but which, in the FIG. 5. Optic nerve entrance. (Drawn by E. E. from a lantern projection of a slide. ) R. Retina ; S. Sclera ; 0. Optic nerve ; V. Central vessel. sclerotic portion, blends with the adjacent sclera, with which it appears to be continuous. It is as though the FIG. 6. Semi-diagrammatic representation of lining of the canal of entrance of the optic nerve. R. Retina ; Ch. Choroid ; L.v. Lamina vitrea of choroid. The inturned selvedge edge E of the scleral tissue, which lines the choroidal part of the canal, ceases at the lamina vitrea. Sc. Sclera ; Opt. Optic nerve. (Modified from Salzmann.) sclera around the inner foramen ended in a selvedge edge, which is carried up clear to the membrane of Bruch ; scleral tissue thus lines the whole of the optic canal (Fig. 6) 14 GLAUCOMA There has been much dispute as to the exact nature of this lining, and for this reason Salzmann has preferred to describe it by the indefinite and non-committal name of " the border tissue." It is generally accepted that fibrous tissue elements from this border tissue extend into the framework of the optic nerve, and so help to form the cribriform plate. Differences of opinion exist (1) as to whether elements derived from the choroid take any part in the formation of the fibrous tissue framework of this part of the nerve, and (2) as to the exact part played by other tissues. It is important to understand that the framework or scaffolding of this part of the nerve is derived from two sources (1) the mesodermal, which we have just been discussing, and (2) the ectodermal. The latter tissue is usually spoken of as " neuroglia " or " glia." Considerable differences of opinion exist as to the exact relationship of these two sets of tissue within the intra-ocular portion of the optic nerve. Such discussions are to a large extent academic. It is, however, of much greater and of more practical interest to note that the supporting tissue found in this portion of the nerve varies very greatly both in its distribution and in its amount. Thus, according to Fuchs, we find in some cases a tendency for a large amount of this tissue to he in bundles along the direction of the length of the nerve, and so to run from before backwards, whilst in others it consists of sheets or laminae, which cross the nerve trunk at right angles to its course and which may, and often do, run clean across all round from the marginal ring of the canal of the optic nerve to the central vessels. Moreover, these laminae may vary in number, in strength, and in completeness. These points are well illustrated by a comparison of Figs. 7, 8, and 9. In Fig. 7 it will be ob- served that the large number of strong lamellae, superposed upon each other, give the lamina cribrosa a considerable depth as measured from before backward, whilst in Figs. 8 and 9 the paucity of lamellae has diminished the depth of that membrane. Nor is this all that can be learnt from these illustrations. The strength of the individual lamellae, PRELIMINARY 15 apart altogether from their number, is obviously greater in the nerve depicted in Fig. 7 than in Figs. 8 and 9. Still R- FIG. 7. The transverse lamellae are here very strong and are also very numerous. The result is that they build up a thick strong lamina cribrosa. The longitudinally placed glial elements are relatively poorly marked in this drawing. one more point, the lamellae are not always of even strength right across the section of the nerve ; indeed they appear O.N. R- FIG. 8. The transverse lamellae lie mainly in the anterior part of the optic canal, and are not very strong, as compared with the glial tissue which lies in bundles along the length of the nerve. to vary widely in this respect. If one may illustrate the point : In one case the membrane may be attached to the canal all round its circumference and may stretch across 16 GLAUCOMA the whole section of the nerve ; in another, only a part of the membrane may be present, the remainder being wanting or weak. Granted then such differences in the number, thickness, and completeness of the individual lamellae, it must be at once obvious that not only will there be great differences in the resistance to pressure of the laminae cribrosae thus built up in different eyes, but also that similar differences will surely be found in different parts of this membrane, even in the same eye. Fuchs O.N. FIG. 9. This resembles Fig. 8, except that the transverse lamellae lie mainly in the posterior part of the canal (the usual arrangement) and the longi- tudinally placed glial bundles are not quite so strongly in evidence. FIGS. 7, 8 and 9 are diagrammatic representations, constructed from Fuchs' microphotographs, and modified in accordance with the text of his article to make the points he emphasises clearer. The lettering is the same in all. R. Retina ; Ch. Choroid ; S. Sclera ; O.N. Optic nerve. believes that those laminae cribrosae, whose elements are mainly made up of transversely running lamellae (Fig. 7), must be much more resistant to pressure applied, as intra- ocular pressure always must be, along the axis of the nerve, than are those in which the bulk of the tissue is built up of bundle-like elements, which run in the direction of the long axis of the nerve (Fig. 8). This proposition is self-evident, for the transverse lamellae, tethered as they are to the sides of the canal of the optic nerve, will check even the slightest tendency to a push of the nerve directly PRELIMINARY 17 backwards, whilst the bundles, which run in the axis of the nerve, will readily be displaced, along with the structures between which they lie. There is another point, of which we were not ignorant, but which has been emphasised for us by Fuchs in his paper under reference, viz., that the situation of the lamina cribrosa varies greatly in different eyes. This of course depends (1) on the position at which the various connective tissue lamellae, which between them form the lamina, find their attachment to the waUs of the optic canal, and (2) on the number of these lamellae. Figs. 7, 8, and 9 illustrate these points clearly. For convenience' sake, we shall take them in reverse order. In Fig. 9, the lamina cribrosa lies in what is usually described as its normal position, i.e., in the posterior segment of the canal. In Fig. 8 it lies almost wholly in the anterior portion of the canal. Fig. 7 forms a contrast with both of the preceding ones, since in it the lamina appears to occupy practically the whole length of the canal. It is obvious, as Fuchs has pointed out, that these variations in anatomical structure must greatly influence the ophthalmoscopic appearances presented by different cases of optic atrophy, unaccompanied by increase of pressure ; in the first case taken above (Fig. 9), the cup would be much deeper than in either of the others (Figs. 7 and 8), that is, if we assume that the underpressed anterior surface of the lamina cribrosa forms the floor of the cup. We shall have to return to this subject when discussing the diagnosis and pathology of the glaucoma cup. Many of the other points which have been dealt with in this section, will be taken up at greater length in their appro- priate places. REFERENCES ELLIOT, R. H. " The Yielding of the Optic Nerve-head in Glaucoma," Brit. Journ. Ophth., July 1921, vol. v. p. 307. FUCHS, E. " On the Lamina Cribrosa," Arch. f. 0., 1916, vol. xci. Part III. MAGGIORE, L. " The Canal of Schlemm in Man," Annul, di Ottal. e Clin. Ocul, May-June 1917. 2 18 GLAUCOMA MAGITOT, A. Ann. d'ocul, vol. cliv. pp. 272, 334, 385; and Amei. Journ. Ophth., 1918, vol. i. p. 587. MORAX, V. Glaucoma e' Glaucoma'eux, Gaston Doin, Editeur, 8 Place de L'Odeon, Paris, 1921, pp. 88 and 89. RocHON-DuviGNEAUD. -The Topography of the Angle of Ihe Anterior Chamber, Paris, 1892. SALZMANN, M. Ana'omy and His'ology of the Human Eyeball, trans. by Dr. E. V. L. Brown, Univ. of Chicago Press, Chicago, 1912, pp. 90 and 91. THOMSON, A. The Ophthalmoscope, 1910, vol. viii. p. 608; and 1911, vol. ix. p. 470. PART III Historical To review the history of glaucoma would be a task which would far transcend the limits of the present work. Interesting as such an undertaking might prove, it would yield the reader little of practical value in return. Hence the decision to take up but a few of the outstanding land- marks of the subject, and to deal with them only in the rough. They loom so large in the dim back pages of the history of ophthalmology, that it would be a poor compli- ment either to the great names linked for ever with them, or to the reader's intelligence, to accord them any different treatment. Over four centuries before the dawn of the Christian era, Hippocrates, in the course of his aphorisms, enumer- ated the diseases of advancing years, and mentioned the " glaucoses " as amongst the known affections of the eyes (o$6a\fji(av Kal piv&v 7/30x77x69, d/z/3/\,uw7rtat,