BERKELEY lERARY WVEBSM7 or CALIFOBMrA FROM THE OPTOMCTRIC LIRRARY OF MONROE JEROME HIRSCH J^/l THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA GIVEN WITH LOVE TO THE OPTOMETRY LIBRARY BY MONROE J. HIRSCH, O.D., Ph.D. DISEASES OF THE EYE SWANZY'S HANDBOOK DISEASES OF THE EYE AND THEIR TREATMENT EDITED BY LOUIS WERNER, M.B., F.R.C.S.L, Sen. Mod. Univ. Dub. SURGEON TO THE ROYAL VICTORIA EYE AND EAR HOSPITAT, OPHTHALMIC SURGEON TO THE MATER HOSPITAL, PROFESSOR OF OPHTHALMOLOGY, UNIVERSITY COLLEGE, DUBLIN, AND EXAMINER IN OPHTHALMOLOGY, DUBLIN UNIVERSITY ELEVENTH EDITION WITH ILLUSTRATIONS LONDON H. K. LEWIS, 136 GOWER STREET, W.C. 1915 OPTOMETRY "(f^ dC London H. K. LEWIS, 136 GOWER STREET, W.C. PREFACE oero In this edition, the first which has appeared since the death of my esteemed friend and colleague the late Sir Henry Swanzy, I have carefully avoided making any change in the general plan or character of the book. The text has again been completely revised and brought up to date, with the result that a considerable amount of new matter has been incorporated, but without any notable increase in the number of pages. The Chapter on the Pupil, which was omitted in the last edition, has now been restored to its place. In the chapter on Glaucoma, the trephine operation has been dealt with in greater detail, and a description of Schiotz's tonometer has been added. The Diseases of the Retina have been to some extent re-arranged ; Hsemorrhagic Retinitis is no longer treated as a separate entity, but is referred to under Thrombosis of the Retinal Vein, while a separate paragraph is allotted to Retinal Haemorrhages in general ; Angio-sclerosis and obstruction of the Retinal Circulation receive more attention than heretofore, and Capillary Angiomatosis of the Retina and Massive Exudation are briefly described. The chapter on Nystagmus has been altered and amplified, and now includes a brief account of Vestibular Nystagmus. Numerous minor improvements and additions have been made, amongst which may be mentioned the introductory paragraphs to Chapters V, VI, X, and XIX, the articles on CEdema of the Eyelids, Artificial Eyes, Maddox's Wing Test for Heterophoria, etc. Many new illustrations have also been added. I have again to thank Dr. Kathleen Lynn for the care and trouble which she has taken in the preparation of the index. L. Werner. 31, Merrion Square, Dublin. PREFACE TO THE TENTH EDITION In the present edition, as in the previous ones, the endeavour has been to keep the book abreast of modern ophthalmology, in so far as this is possible in a work of its size, mainly intended for students. The amount of text is about the same as before, although, in con- sequence of an alteration in the shape of the book, the number of pages is less. The chapters are differently arranged, with the result that the earlier ones now treat of the normal eye and its functions, and the methods for examining them. The book has been thoroughly revised throughout, obsolete matter having been discarded, while new developments have been introduced. The book now, for the first time, contains coloured figures, to the number of twenty-one, from original paintings by one of us (L. W.), and it is believed that these w^ill prove helpful to the student. Our thanks are due to Dr. Kathleen Lynn for the great pains she has taken in the preparation of the index. We desire also to express our thanks to Mr. H. K. Lewis for the care he has given to the production of the book and for his readiness to carry out all our suggestions. H. R. S. L. W. Dublin, CONTENTS CHAPTER I. PAGE Preliminary Note on the Clinical Examination of Eye Patients . 1 Optical Structure and Functional Examination of the Eye . . 2 Refraction — Accommodation — The Mechanism of Accommodation — The Far Point and the Near Point — The Amplitude and Range of Accommodation — Connection between Accommodation and Convergence (Relative Accommodation)^ — Convergence — Range and Amplitude of Convergence ..... 4 The Sense of Sight (Light- Sense, Colour- Sense, Form- Sense) . . 10 The Field of Vision — Perimetry — Pathological Defects in the Field of Vision — Perception of Colours in the Periphery of the Field • — Perception of Form in the Periphery of the Field . . .17 CHAPTER 11. THE OPHTHALMOSCOPE. Laws of Reflection— Images formed by Plane and Concave Mirrors — How to distinguish Plane and Concave Mirrors . . .26 The Ophthalmoscope — Why Necessary — Helmholtz's Ophthalmo- scope — Modern Ophthalmoscope — Direct Method — Indirect Method 27 Detection of Opacities in the Refractive Media by aid of the Oph- thalmoscope ......... 35 The Normal Fundus Oculi as seen with the Ophthalmoscope — The Optic Disc or Optic Papilla — The Retina — The- Macula' Lutea — The General Fundus Oculi — The Retinal Vessels ... 36 CHAPTER III. DISEASES OF THE CONJUNCTIVA. Preliminary Note — The Examination of the Conjunctiva . . 42 Hypersemia — Conjunctivitis in General (Causes — Diagnosis — Varieties) — Bacteriology of Conjunctivitis — Catarrhal, Simple, Acute, or Muco-purulent Conjunctivitis — Diplobacillary or CONTENTS Angular Conjunctivitis — Chronic Simple, or Chronic Ca- tarrhal, Conjunctivitis — Acute Blennorrhoea of the Conjunctiva, or Purulent Ophthalmia — Membranous Conjunctivitis (Croupous and Diphtheritic) — Hay Fever — Trachoma. Granular Con- junctivitis, or Granular Ophthalmia (Acute and Chronic) — Fol- licular Conjunctivitis — Tubercular Disease — Parinaud's Con- junctivitis — Ophthalmia Nodosa — Sporotrichosis — Lupus — Syphilis — Ulcers of the Conjunctiva — Spring Catarrh, or Vernal Conjunctivitis — Pemphigus — Conjunctivitis Petrificans — Sub- conjunctival Ecchymosis — Subconjunctival Serous Effusion, or Chemosis — Emphysema — Injuries — Degenerative Diseases — Pinguecula — Epithelial Plaques — Pterygium — Lithiasis — Xerosis or Xerophthalmia — Hj^aline, Colloid, and Amyloid Degeneration 93 Cysts — Simple Cysts — Sub-conjunctival Cysticercus . . .98 Tumours — Dermo-Lipoma — Osteoma — Naevus, or Mole — Hseman- gioma — Polypus and Granuloma — Lj^iiphoma — Papilloma, or Papillary Fibroma — Epithelioma — Sarcoma — Tumours of the Caruncle 99 CHAPTER IV. PHLYCTENULAR CONJUNCTIVITIS AND KERATITIS. Solitary, or Simple, Phlycten of the Conjunctiva — Multiple, or Miliary, Phlyctens of the Conjunctiva — Primary Phlyctenular Keratitis 102 CHAPTER V. DISEASES OF THE CORNEA. Introduction . . . . . . . . . .110 Clinical Methods of Examining the Cornea . . . . .110 Inflammations of the Cornea — (a) Ulcerative Inflammations — Simple Ulcer — Deep Ulcer — Serpiginous Ulcer — Marginal Ring Ulcer — Diplobacillus Ulcer — Rodent Ulcer — Keratomalacia — Neuro- paralytic Keratitis — Herpes Corneae Febrilis — Dendriform Keratitis — Bullous Keratitis — Filamentary Keratitis — Keratitis Aspergillina . . . . . . . . .112 (6) Non-Ulcerative Inflammations — Abscess — Ring Abscess — Syphilitic Diseases (Diffuse Interstitial Keratitis — Specific Punctiform Interstitial Keratitis — Gumma) — Nodular, and Reticular Keratitis — Discoid Keratitis — Tubercular Keratitis — Keratitis Punctata — Sclerotising Opacity — Ribandlike Keratitis — Superficial Epithelial Dystrophy . . . . .136 Ectasies of the Cornea — Staphyloma — Conical Cornea — Atrophic Marginal Degeneration . . . . . . . .146 Tumours of the Cornea . . . . . . . .153 CONTENTS Injuries of the Cornea — Foreign Bodies — Losses of Substance, or Abrasions — Recurrent Abrasion, or Disjunction — Haemorrhagic Discoloration — Blows — Injuries with Caustic Substances — Per- forating Injuries . . . . . . . . .153 Opacities of the Cornea — Nebula, Macula, Leucoma — Arcus Senilis 160 CHAPTER VI. DISEASES OF THE SCLEROTIC. Introductory — Episcleritis — Deep Sclerotis — Gumma — Tubercle — Brawny Scleritis . . . . . . . .164 Tumours — Pigment Spots . . . . . . . .168 Injuries . . . . . . . . . . .168 Staphyloma — Coloboma — Congenital Defects . . . .171 CHAPTER VII. DISEASES OF THE UVEAL TRACT. Inflammations of the Iris, or Iritis — Acute Iritis . . , .173 Syphilitic — Gonorrhoeal — Tubercular — Rheumatic . . .177 Chronic Iritis or Irido-cyclitis . . . . . . .183 Inflammations of the Ciliary Body, or Cyclitis — Acute — Chronic — Syphilitic — Gumma — Tubercular Cyclitis . . . .187 Inflammations of the Chorioid, or Chorioiditis — Disseminated — Central Senile Guttate — Central — Syphilitic Chorioido-Re- tinitis — Purulent Chorioiditis . . . . . .189 Sympathetic Ophthalmitis and Sympathetic Irritation — Injuries of the Iris — Foreign Bodies — Iridodialysis — Retroflexion — Rup- ture of the Sphincter — Dehiscence — Aniridia — Mydriasis and Miosis • . 193 Injuries of the Ciliary Body — Punctured Wounds and Foreign Bodies . . . . . . . . . .214 Injuries of the Chorioid — Foreign Bodies — Incised Wounds — Rupture — Extravasation of Blood . . . . . . .214 New Growths of the Iris — Cysts — Granuloma — Solitary Tubercle — Sarcoma — Carcinoma — Ophthalmia Nodosa . . . .216 New Growths of the Ciliary Body — Sarcoma — Myosarcoma — Car- cinoma . . . . . . . . . .217 New Growths of the Chorioid — Sarcoma — Carcinoma — Tubercle — Sarcoma .Carcinomatosum, Osteo-Sarcoma, and Lymphoma . 217 Other Diseases of the Chorioid — Posterior Staphyloma — Detach- ment — Central Senile Areolar Atrophy . . . . .221 Malformations of the Iris — Heterophthalmos — rCorectopia — Polycoria — Persistent Pupillary Membrane — Coloboma . . .223 Malformations of the Chorioid — Coloboma — Alterations in the Colour of the Iris — Albinismus ....... 224 Operations on the Iris . . . . . . . .225 CONTENTS CHAPTER VIII. THE PUPIL. pa(;e Contraction of the Pupil — Dilatation of the Pupil — Action of Mydri- atics — Action of Miotics . . . . . . .229 CHAPTER IX. GLAUCOMA. Primary Glaucoma — Schiotz Tonometer — Chronic Simple Glaucoma — Acute Glaucoma — Subacute Glaucoma — Etiology — Pathology — Treatment .......... 235 Secondary Glaucoma — Haemorrhagic Glaucoma .... 258 Congenital Glaucoma, or Hydrophthalmos ..... 260 CHAPTER X. DISEASES OF THE CRYSTALLINE LENS. Introduction — Complete Cataracts — Senile Cataract — Complete Cata- ract of Young People — Diabetic Cataract — Glass-Blower's Cataract — Black Cataract . . . . . . .201 Partial Cataracts — Central Cataract — Zonular, or Lamellar, Cataract — Punctate Cataract — Anterior Polar, or Pyramidal Cataract — Fusiform, or Spindle-shaped Cataract — Posterior Polar Cataract 269 Secondary Cataract — Posterior Polar Cataract — Total Secondary Cataract .......... 272 Capsular Cataract ......... 273 Traumatic Cataract . . . . . . . . .273 Operations for Cataract — Extraction — Linear Extraction — The Combined Operation — Extraction without Iridectomy — Ex- traction in the Capsule . . . . . . .275 Discission ........... 293 Dislocation of the Lens . . . . . . . .294 Congenital Defects of the Lens — Ectopia — Coloboma — Lenticonus 9( Aphakia ........... 295 CHAPTER XL DISEASES OF THE VITREOUS HUMOUR. Purulent Inflammation — Other Inflammatory Affections — Haemor- rhage — Muscae Volitantes — Synchysis — Synchysis Scintillans . 298 Foreign Bodies — Rontgen Rays for Detection of Foreign Bodies — The Sideroscope — Removal of Foreign Bodies — The Magnet . 303 Cysticercus — Blood Vessels — Persistent Hyaloid Artery . . .311 CONTENTS CHAPTER XII. DISEASES OF THE RETINA. PAGE Alterations in the Retinal Circulation — Hyperemia and Anaemia — Pulsation of Vessels . . . . . . . .313 Inflammations — Retinitis — Syphilitic, Albuminuric, Diabetic, Leu- coemic, Metastatic . . . . . . . .314 Retinal Haemorrhages and Allied Diseases — Retinitis Proliferans — Retinitis Exudativa — Retinitis Circinata — Capillary Angio- matosis .......... 320 Diseases of the Retinal Vessels — -Sclerosis — Obstruction of the Central Artery — Tlirombosis of the Central Artery — Thrombosis of the Retinal Vein — Quinine Amaurosis — Amaurosis from Filix Mas 323 Atrophies, or Degenerations — Retinitis Pigmentosa — Retinitis Punctata Albescens — Gyrate Atrophy . . . . .328 Injury of the Retina by Strong Light — Direct Sunlight — Snow- Blindness — Electric Light . . . . . . .331 Tumours of the Retina — Glioma — Tubercle ..... 334 Parasitic Disease of the Retina — Cysticercus . . . . .335 Detachment of the Retina . . . . . . . .336 Traumatic Affections of the Retina — Ana?sthesia — Commotio Re- tinae — ' Holes ' at the Macula Lutea ..... 339 CHAPTER XIII. DISEASES OF THE OPTIC NERVE. Optic Neuritis (Papillitis), due to : Cerebral Tumours — Tubercular Meningitis — Hydrocephalus — Tumours of the Orbit — Inflam- matory Processes in the Orbit — Exposure to Cold — Suppression of Menstruation — Chlorosis — Syphilis — Rheumatism — Lead- Poisoning — Peripheral Neuritis — Disseminated Sclerosis — Tabes Dorsalis — Hereditary Predisposition — Certain Fevers . .341 Retro-Bulbar Optic Neuritis — Optic Neuritis Associated with Per- sistent Cerebro- Spinal Rhinorrhoea . . . . .347 Toxic Amblyopia (Axial Neuritis) ...... 349 Atrophy of the Optic Nerve, due to : Optic Neuritis — Pressure — Embolism of the Central Artery — Syphilitic Retinitis — Retinitis Pigmentosa — Chorioido-Retinitis ...... 353 Primary Atrophy, due to : Hereditary Predisposition, with Disease of the Spinal Cord, as a Purely Local Disease, from Poisoning with Organic Preparations of Arsenic ..... 354 Tumours of the Optic Nerve — Hyaline Outgrowths . . . 357 Injuries of the Optic Nerve ....... 357 Amblyopia due to Haemorrhages from the Stomach, Bowels, or Uterus — Glycosuric Amblyopia ....... 357 CONTENTS CHAPTER XIV. PART I. pa(;e OCULAR DISEASES AND SYMPTOMS LIABLE TO ACCOMPANY FOCAL DISEASE OF THE BRAIN. Hemianopsia — Arrangement of the Cortical Visual Centres, their Relations to the Retina, and the Course of the Optic Fibres between these Two Points — Localisation of the Lesion in Hemianopsia — Word -Blindness — Visual Aphasia — Dyslexia — Amnesic Colour-Blindness — Visual Hallucinations — Mind- Blindness, or Optic Amnesia ...... 3G0 PART II. OCULAR DISEASES AND SYMPTOMS LIABLE TO ACCOMPANY CERTAIN DIFFUSE ORGANIC DISEASES OF THE BRAIN. Disseminated Sclerosis of the Brain and Spinal Cord — Diffuse Sclerosis of the Brain — General Paralysis of the Insane — Am- aurotic Family Idiocy — Maculo-cerebral Degeneration — Menin- gitis — Traumatic Meningitis — Hydrocephalus — Infantile Para- lysis — Paralysis Agitans — Epilepsy — Chorea . . . ,372 FART III. OCULAR DISEASES AND SYMPTOMS LIABLE TO ACCOMPANY CERTAIN DISEASES AND INJURIES OF THE SPINAL CORD. Tabes Dorsalis — Hereditary Ataxy — Myelitis — Syringomyelia — Myo - tonia Congenita — Acute Ascending Paralysis — Injuries of the Spinal Cord 379 PART IV. NERVOUS AMBLYOPIA, OR NERVOUS ASTHENOPIA. Nervous Amblyopia in Neurasthenia — Nervous Amblyopia in Hysteria — Nervous Amblyopia in Traumatic Neurosis . . 383 PART V. VARIOUS FORMS OF AMBLYOPIA. Transitory Hemianopsia, or Scintillating Scotoma — Congenital Amblyopia — Amblyopia during Pregnancy — Reflex Amblyopia — Night-Blindness — Ura3mic Amblyopia — Pretended Amaurosis — Erythropsia 390 CONTENTS CHAPTER XV. ELEMENTARY OPTICS. PAGE Divergence and Parallelism of Rays of Light — Refraction — Index of Refraction — Plane Glass — Prisms — Spherical Lenses — Optical Defects of Lenses — Sphero-Cylindrical and Toric Lenses — Cylindrical Lenses — Numbering and Decentration of Lenses — Protective Glasses ....... 396 CHAPTER XVI. ABNORMAL REFRACTION AND ACCOMMODATION. Ametropia — Myopia — Definition and Causes of M, — Punctum Remotum in M. — Optical Correction of M. — Diagnosis and Determination of Degree of M. — Amplitude and Range of Accommodation in M. — Angle Gamma in M. — Etiology of M. — Non-Progressive M. — Symptoms of M. — Complications of Pro- gressive M. — Pernicious M. — Functional Anomalies attendant upon Progressive M. — Management of ]\I. — The Prescribing of Spectacles in M. — Operative Cure of M. . . . . .414 Hypermetropia — -Definition, and Optical Causes of H. — Punctum Remotum in H. — Optical Correction of H. — Determination of Degree of H. — Amplitude and Range of Accommodation in H. — Angle Gamma in H. — Varieties of H. in relation to Accom- modation — Etiology of H. — Symptoms of H. — Accommodative Asthenopia in H. — Internal Strabismus in H. — The Prescribing of Spectacles in H 428 Astigmatism — Varieties of As. — Symptoms of Regular As. — Estima- tion of Degree of, and Correction of As. — The Astigmometer — Lental As. — Irregular As. ....... 436 Anisometropia . . . . . . . . . .447 Estimation of the Refraction by Aid of the Ophthalmoscope . .447 Retinoscopy . . ... . . . . . . 452 Anomalies of Accommodation — Presbyopia — Paralysis of Accom- modation — Accommodative Asthenopia — Spasm of Accommo- dation .......... 460 CHAPTER XVII. THE ORBITAL MUSCLES AND THEIR DERANGEMENTS. Normal Action of the Orbital Muscles — Inclination of the Vertical Meridian in the Several Principal Positions — ]\Iuscles called into Action in the Several Principal Positions — Subjective and Objective Localisation — The Field of Fixation . . . 466 CONTENTS Strabismus — Latent Strabismus, or Heterophoria — Binocular Vision and Sense of Fusion — Diplopia ..... 472 Paralyses of the Orbital Muscles — General Symptoms — Paralysis of the External Rectus — Paralysis of the Superior O liquc — Paralysis of the Internal Rectus, Superior Rectus, Inferior Oblique, and Levator Palpebrse — Mnemonic Diagrams — Mea- surement of the Degree of Paralysis — Causes of Paralysis of Orbital Muscles — Ophthalmoplegic Migraine — Ophthalmoplegia Externa, or Nuclear Paralysis — Fascicular Paralyses — Myas- thenia Gravis — Cerebral Paralysis of Orbital Muscles — The Localising Value of Paralyses of Orbital Muscles in Cerebral Disease — Congenital Defects of Motion ..... 476 Convergent Concomitant Strabismus — Causes — Single Vision in — Amblyopia of Squinting Eye — Clinical Varieties of — Measure- ment of — Mobility of Eye in — Treatment — Optical Treat- ment — Orthoptic Treatment — Operative Treatment — Tenotomy — Advancement of External Rectus — Dangers of the Strabismus Operation — Treatment subsequent to Operation . . , 506 Divergent Concomitant Strabismus . . . . . .525 Latent Deviations (Heterophoria) — Tests for Latent Deviations — Symptoms — Treatment — Latent Torsion — Insufficiency of Convergence — Spasm of the Orbital Muscles — The Diplcscope — Harman's Test 526 Nystagmus — Amblyopic Nystagmus — Coal Miner's Nystagmus— Vestibular Nystagmus — Nystagmus in Diseases of Nervous System 536 CHAPTER XVIII. DISEASES OF THE EYELIDS. Eczema — (Edema — Marginal Blepharitis (Ophthalmia Tarsi) — Phthei- riasis Ciliorum — Hordeolum (Stye) — Chalazion (Meibomian Cyst, Tarsal Tumour) — Milium — MoUuscum — Nnpvus — Xanthelasma — Chromidrosis — Herpes Zoster Ophthalmicus — Syphilitic Affections — Vaccine Vesicles — Rodent Ulcer — Solid CEdema, or Elephantiasis Lymphangioides — Plexiform Neuroma — Lymphoma — Epithelioma, Sarcoma, Adenoma, and Lupus — Gangrene — Clonic Cramp of the Orbicularis Muscle — Blepharo- spasm — Ptosis — Operations for its Cure — Lagophthalmos — Symblepharon — Blepharophimosis — Canthoplastic Operation — Distichiasis and Trichiasis — Operations for their Cure — Entropion, Spastic Entropion, Senile Entropion, Opera- tions for its Cure — Ectropion — Operations for its Cure — Ihe Restoration of an Eyelid — Ankyloblepharon — Injuries — Epican- thus— Congenital Coloboma . . . . . • .541 CONTENTS CHAPTER XIX. DISEASES OF THE LACRIMAL APPARATUS. PA(.R ivfalposition of the Punctum Lacrimale — Stenosis, and Occlusion of the Punctum Lacrimale — Obstruction of the CanaHcuhis — Stricture of the Nasal Duct — Blennorrhcea of the Lacrimal Sac — Extirpation of the Lacrimal Sac — Acute Dacryocystitis — Dacryoadenitis — Tumours of the Lacrimal Gland — Cysts of the Lacrimal Gland — Symmetrical Chronic Swelling of the Lacrimal and Salivary Glands — Extirpation of the Lacrimal Gland . , Mi) CHAPTER XX. DISEASES OF THE ORBIT. Exophthalmos — Orbital Cellulitis — Tenonitis — Periostitis of the Orbit — Caries of the Orbit — ^Injuries of the Orbit — Enophthalmos — Orbital Tumours — Hernia Cerebri — Cysts — Solid Tumours — Symmetrical Tumours — Pulsating Exophthalmos — Intermit- tent Exophthalmos — Tumours of the Optic Nerve — Implication of Neighbouring Cavities — Shrinking of the Conjunctiva- Temporary Resection of the Outer Wall of the Orbit — Exoph- thalmic Goitre ......... 590 APPENDIX Regulations as to Defects of Vision which Discjualify Candidates for Admission into the Civil, Naval, and Military Government Services, the Royal Irish Constabulary, and the Mercantile Marine 625 Index . . . . . . . . . . .63' TO THE STUDENT. The student may at first omit the portions printed in small type, and those marked with an asterisk, including the whole of chapter xiv. With these exceptions he should carefully read chapters i., ii., XV., and xvi., immediately on joining the ophthalmic hospital or department. xvm DISEASES OF THE EYE CHAPTER I. Preliminary Note on the Clinical Examination of Eye Patients. In general medicine and surgery, the importance of systematic clinical methods is well recognised. System is even more necessary in the clinical study of diseases of the eye, where the changes from the normal are often so minute that they may readily escape observation, and the symptoms depending on derangement of the functions of the organ are sometimes such, that the patient may himself be unaware of them. Before examining the eye, a general observation of the patient should be made, whereby suggestive hints are often obtained for diagnosis. For example : the manner m which a patient enters a room may help to distinguish between an affection of the nervous apparatus of the eye and cataract, or his gait may suggest an affec- tion associated with disease of the spinal cord. Again, a strumous appearance, enlarged glands, eczema, syphilitic eruptions, or the aspect due to hereditary syphilis afford information not to be disregarded. There are many obvious local conditions, which are liable to escape the attention of a beginner who is, as so many are inclined to be, too hasty in his desire to make a close inspection of the eyeball itself ; for example, the presence of slight strabismus, photophobia, slight ptosis, or the sleepy appearance due to the heavy thickened lid in granular ophthalmia. We mention these merely to indicate the advantages which may be gained by quietly taking a general view of the patient, and of his eyes, at a little distance, before proceeding to examine the latter more closely. The examination of the eye may be divided into three parts, 1 DISEASES OF THE EYE. [chap. t. which are usually taken in the following order : 1. Objective examination in daylight. 2. Subjective, or functional, examina- tion. 3. Objective examination in the dark room. All these will be described in their appropriate places in the following pages, and it is only necessary here to mention some of their subdivisions. Under the first will come inspection (and palpation when possible) of the orbit, eyelids, lacrimal passages, conjunctiva, cornea, anterior chamber, iris (its colour and structure, and the mobility, shape, and size of the pupil), anterior layers of the lens in the pupillary area, and testing the intra-ocular tension. The second will include tests for acuteness of vision, field of vision, accommodation, binocular vision, orbital muscles, colour-vision, and light-sense. Finally, in the dark room the anterior parts of the eye, including the lens, and sometimes the anterior portion of the vitreous humour, are first examined by reflected light, with oblique illumination, and then with a strong -\- lens in the ophthalmoscope. The details of the fundus are then observed with the ophthalmoscope, and the refrac- tion is estimated if necessary. One should never omit to compare the affected eye with its fellow, if only one eye be diseased. It is not intended that all these methods of examination should be put into use, or considered even necessary, in every case ; but they should be borne in mind, if nothing is to escape attention. OPTICAL STRUCTURE AND FUNCTIONAL EXAMINATION OF THE EYE. Optical Structure of the Eye. — The eye is a dark chamber lined by the uveal pigment, which prevents the rays of light from entering the eye, except through the transparent media and pupil. It possesses three refracting or dioptric ^ media, limited by three convex surfaces. The dioptric media are the aqueous humour, the substance of the crystalline lens, and the vitreous humour. The convex surfaces are the anterior surface of the cornea,^ and the anterior and posterior surfaces of the crystalline lens. 1 The phenomena of refraction are sometimes referred to as Dioptrics, and those of reflection as Catoptrics. 2 The posterior surface of the cornea may be neglected, since it is parallel to the anterior surface, and the index of refraction of the cornea is the same as that of the aqueous humour. CHAP. I.] OPTICAL STRUGTVUE OF THE EYE. 3 By aid of this apparatus, which is called the Dioptric System of the eye, distinct inverted images of external objects are formed on the retina, in the same way as images are formed by a convex lens (see § 22, chap. xv.). The refracting surfaces, which are practically spherical, are centred on the Optic Axis (0 P, Fig. 1), an imaginary line which, passing through the optical centre (N) of the eye, meets the retina at a point (P), the posterior principal focus (§ 15, chap, xv.), slightly to the inner side of the macula lutea (M). The optic axis of the eye is similar to the principal axis of a convex lens (see § 14, chap. XV.). The optical centre N, which is called the Nodal Point, is situated just in front of the posterior surface of the lens, and rays Fig. 1.— P, Optic axis ; FM, Vis^ passing through it are not "^^^^."^' ^/ F angle y; ^.centre of T . , T. ,T . ,1 1 . rotation ; iV, nodal point , C, centre of deviated m their path, being cornea in fact secondary axes (§ 14, chap. XV.). F M is the Visual Line, which unites the object looked at (called the point of fixation) with the macula lutea (M) and passes through the nodal point. The Line of Fixation {R V) joins the centre of rotation (7?) of the eye with the point of fixation. The angle R V formed at the centre of rotation, by the optic axis and the line of fixation, is called the angle y.^ The line of fixation and the visual line so nearly coincide that in practice we regard them as identical ; and hence the angle y is practically the same as iV F. The angle k is the angle between the fixation line and a per- pendicular line through the cornea, opposite the centre of the pupil. In practice it is the angle k which is measured. It is not 1 Some writers call this angle a (alpha). But the angle a originally- meant the angle between the visual line and the major axis of the corneal ellipse, and was founded on the view that the cornea was an ellipsoid — a view which has been shown to be erroneous by Tscherning and others. Indeed, the " working area," or optical portion of the cornea, which includes 13° to 16°, is approximately spherical. DISEASES OF THE EYE. .[chap. 1. equal to the angle y, because the centre of the pupil is a little to the inner side of the centre of the cornea. In order to measure the angle k, the eye is placed at the peri- meter (p. 17) as for an examination of its field of vision, that is to say, looking at the zero point. A candle flame is then moved along the arc of the perimeter, until the corneal image of the light appears to the observer (whose eye is in a line with the candle and its image) to be in the centre of the pupil. The number on the arc of the perimeter opposite the candle gives the value of the angle k, the average size of which is 5°. Refraction. By the Refraction of the Eye is meant, in a general sense, the faculty it has when at rest (i.e., without an effort of accommoda- FiG. 2. tion) of altering the direction of rays of light which pass into it, making parallel rays convergent, and divergent rays less divergent. But, as usually understood, it means the relation which the position of the retina bears to the principal focus of the dioptric system. In Normal Refraction, or Emmetropia (e/xyaerpoi/, the standard ; o>i//, the eye), as it is termed, the retina lies at the posterior principal focus (Fig. 2), and therefore parallel rays are brought to a focus on the layer of rods and cones of the retina, and form on it a dis- tinct inverted image of the point or object from which they come. The emmetropic eye, in a state of rest, is thus adapted for seeing distant objects, and its far point (punctum remotum) is at infinity. Conversely, if the retina be illuminated, the rays proceeding from any point on it will emerge from the eye parallel. In the normal eye the posterior focal length of the dioptric system is 23 mm. OPTICAL STRUCTURE OF THE EYE. and the average length of the eyeball including the sclerotic is 24 mm. Accommodation. The eye can see near objects distinctly as well as distant objects, although the rays from any given point (a, Fig. 3) of a near object reach the eye with a divergence so considerable, that they could not be brought to a focus on the retina by the unaided refrac- tion, but would converge towards a point their conjugate focus a' (§16, chap, xv.), namely behind the retina, and would not form a distinct image on the latter, but merely a blurred image or circle of diffusion (at h c). It is obvious, therefore, that an increase of refracting power in the eye is necessary, in order that near objects riG.^3. may be distinctly seen. It is this increase in the refracting power for the purpose of near vision which is called Accommodation. The Mechanism of Accommodation is as follows : — The ciliary muscle (m. Fig. 4) contracts, thus drawing forward the chorioid and the ciliary processes, and relaxing the zonula of Zinn {z), which is attached to the latter. The lens {I), which was flattened by the tension of the zonula, is now free to assume a more spherical shape, in response to its own elasticity. The posterior surface of the lens scarcely alters in shape, being fixed in the patellary fossa ; but the anterior surface becomes more convex, thus increasing its refracting power. Associated with the act of accommodation is a contraction of the pupil. The accompanying figure (Fig. 4) represents the changes which take place in accommodation, the dotted lines indicating the latter state. Tscherning has shown that the increased curvature of the anterior surface of the lens occurs mainly in the centre of that surface — in other words, that in accommodation the anterior surface becomes somewhat conical, and not merely more spherical, 6 DISEASES OF THE EYE. [chap. i. During accommodation, owing to relaxation of the suspensory ligament, the lens sinks down a little, and becomes tremulous on movement of tlie eye, and there is no increase in the intra-ocular tension. Accommodation is always associated with contraction of the pupil and convergence of the optic axes. The Far Point and the Near Point.— It is possible for the eye, Fig. 4. — c, cornea ; a, anterior chamber ; I, lens ; v, vitreous humour ; i, iris ; z, zonula of Zinn ; m, ciliary muscle. by changing the accommodation, to see objects accurately at every distance from its Far Point — i.e., its most distant point of dis- tinct vision (Punctum Remotum, — R.), up to a point only a few centimetres from the eye, called the Near Point (Punctum Proxi- mum, — P.). We can find the latter by directing the patient to look at a page printed in small type, and by bringing it slowly closer and closer to his eye, until a point is reached where he cannot distinguish the words and letters, which become blurred. A point very slightly more removed from the eye than this, where he can read distinctly, is the near point. Between the near point and the eye vision is indistinct, because no effort of the ciliary muscle can produce the amount of convexity of the lens required for so short a distance. The Amplitude and Range of Accommodation. — This is the amount of accommodative effort of which the eye is capable — i.e., the effort it makes in order to adapt itself from its Far Point (R.) up to its Near Point (P.). The amplitude of accommodation CHAP. I.] FUNCTIONAL EXAMINATION OF THE EYE. 7 {a), therefore, is equal to the difference between the refracting power of the eye when its accommodation is exerted to the utmost (p), and when at rest (/•), as expressed by the formula a = f — r. It may be represented by that convex lens placed close in front of the eye, which would take the place of the increased convexity of the lens, or, in other words, which would give to rays coming from the nearest point of distinct vision a direction as if they came from the far point. The number of this lens expresses the ampli- tude of accommodation in a given eye. Fig. 5. For example : if, in an emmetropic eye {E, Fig. 5) the near point be situated at 20 cm., then a convex lens (L) of 20 cm. focal length placed close to the eye (between that point and the eye) would give to rays coming from the near point a direction as though they came from a distant object {i.e., would make them parallel), and this normally refracting eye would then be enabled, by aid of its refraction alone, to bring these rays to a focus on the retina. Making use of the above equation, we find in this case — since a focal length of 20 cm. represents a lens of 5 D — that p = 5 and therefore a = 5 — r, but R being situated at infinity (designated by the sign oo) , r = i = i = ; therefore a = 5 — = 5 D.i K 00 ^ It must be observed that R represents the distance of the Far Point from the eye, while r represents the refractive power which is added to the eye by accominodation, or by a lens, in order to adapt it for the dis- tance R. Hence it is evident that r = ^, because the strength, or re- R fractive power, of a lens is inversely as its focal length — e.g., a lens of the strength of 4 D will have a focal length of ^ that of a lens of 1 D — 1 m. 100 cm. „_ / ooo 1 \ o- 1 1 1 1 1 I.e., — — — = =25 cm. (see § 28, ch. xv.). similarly, p = ^ and a = .' P representing the distance of the Near Point, and A the focal length of the lens a which represents the Amplitude of Accomniodation. DISEASES OF THE EYE. [CHAP. I. Fig. 6. — Eye accommodated for which forms a distinct image on the retina, R. Parallel rays now unite in front of the retina at a shorter distance, F. The amplitude of accommodation {i.e., the number of the lens which would represent it) is the same in every kind of refraction, according to the age of the individual, but in emmetropia alone is a = J) a,s above, because in it alone is r = 0. It is evident that, as the refractive power of the eye is increased during accommodation, the eye is rendered temporarily myopic as regards parallel rays (Fig. 6). Under the head of " Anomalies of Accommo- dation," chap, xvi., will be found Bonders' diagram representing the amplitude of accommodation at dif- ferent ages. The Range of Accommodation is the distance between the far point, R, and the near point, P. As will be seen later on, it is not always the same for a given amplitude. Connection between Accommodation and Convergence (Relative Accommo- dation). — By convergence we mean the inward rotation of the eyes which is necessary in looking at a near object, in order to obtain single vision with both eyes. With each degree of convergence of tlie visual lines a certain effort of accommodation is associated. Thus, if the object be situated 2 metres from the eye, the visual lines converge to that point, and a certain effort of accommodation (0*5 D) is made. But this connection between accommodation and convergence is somewhat elastic, for the accommodative effort may be increased or decreased, while the object is kept distinctly in view, and the same convergence maintained. That it may be increased is shown by the experiment of placing a weak concave glass before the eye, when it will be found that the object is still distinctly seen ; or if a weak convex glass be held before the eye the object will also be clearly seen, showing that the accommodative effort may be lessened without affecting vision or convergence. This amplitude of accommoda- tion for a given point of convergence of the visual lines, found by the strongest concave and strongest convex glasses with which the object can still be distinctly seen, is called the Relative Amplitude of Accommo- dation. That part of it which is already in use, and is represented by the convex lens, is termed the negative part ; while the positive part is repre- sented by the concave lens, and has not been brought into play. For sustained accommodation at any distance, it is necessary that the positive part of the relative amplitude of accommodation be considerable in amount. Moreover, the convergence may be altered, while the same effort of accommodation is maintained, as is shown by the experiment of placing a CHAP. I.] FUNCTIONAL EXAMINATION OF THE EYE. 9 weak prism with its base inwards before one eye. In order that the object may then be seen singly, it will be necessary for the eye before which the prism is placed to rotate somewhat outwards ; and it will be found that the individual can do this, while at the same time he sees the object with the same distinctness, showing that the same effort -of accommodation has been maintained, although the angle of convergence of the visual axis is less than before. Convergence. * Range and Amplitude of Convergence. — The nearest point for which the eye can converge and still see single is the Near Point of convergence. The Far Point of Convergence is the point at which the visual lines meet when the eyes are at rest ; as the position of rest is one of slight divergence, this imaginary point usually lies behind the head, and the devia- tion from parallelism to this degree of diver- gence is known as negative convergence. The Amplitude of Convergence is the sum of the positive and negative convergence. The Range of Convergence is the distance be- tween the far and near points of convergence. The near point of convergence is found by bringing an object, such as a fine line, up to the eyes in the middle line, until it begins to be seen double. The far point of convergence, or rather the negative con- vergence, can be measured by prisms placed base inwards while the patient looks at a distant object. In some cases the eyes are parallel or slightly convergent when at rest, and then convergence is altogether positive. Fig. 7. The Unit of Convergence. The Metre Angle. If the visual line {E 1, Fig. 7) of an eye {E) be brought to bear on a point (1, Fig. 7) 1 metre distant from it in the median line {M 1), the angle of convergence {E 1 M = I E D) which the visual line thus makes with the median line is called the Metre Angle. It expresses the degree 10 DISEASES OF THE EYE. [chap. i. of convergence necessary for binocular vision at that distance, and is employed as the unit for expressing other degrees of convergence. If, for example, an object be situated ^ a metro (^, Fig. 7) from the eye, the angle of convergence {E | M) must be practically twice as large as at 1 metre : C. (Convergence) = 2 metre angles. If the object be only | of a metre distant, 3 metre angles are required : C. =3 metre angles. If the object be situated 2 metres from the eye, the angle of convergence will only be one-half as great as that at 1 metre, and here C. = ^ metre angle ; while if the eye be directed towards a distant object (D) there will be no angle of convergence, and if the visual lines be divergent the metre angle will be negative. Now the emmetropic eye normally requires for each distance of bino- cular vision as many metre angles of convergence as it requires dioptrics of accommodation. For a distance of 1 metre an effort of accommodation of 1 dioptre is required, and also 1 metre angle of convergence ; at \ metre from the eye 2 D of accommodation is required and 2 metre angles ; at ^ metre from the eye 3 D of accommodation and 3 metre angles, and so on ; while for distant objects neither convergence nor accommodation is reqviired. The positive portion of the average normal convergence is about 10 metre angles and the negative 1 metre angle. Binocular Vision will be described in chap. xvii. THE SENSE OF SIGHT. The Sense of Sight consists of three Visual Perceptions or Sub- Senses — namely, the Light-Sense, the Colour-Sense, and the Form- Sense. The Light- Sense is the power the retina, or the visual centre, has of perceiving gradations in the intensity of illumination. The light-sense can be tested by Forster's, or by Izard and Chibret's photometer. On looking through the latter towards the sky two equally bright discs are seen. By a simple mechanism one of the discs can be made darker. If the eye does not perceive the difference in illumination between the two discs within 5° its light-sense is abnormal, or we may say its L.D. (Light Difference) is too high. Again, if one disc be made quite dark, and be then gradually lighted, the patient is required to indicate the smallest degree of light, or L.M. (Light Minimum), by which he can observe the disc issuing from the darkness. This should not be more than 1° or 2°. Another good method is that of Bjerrum, in which the light-sense is tested by grey letters on a white ground, the letters being constructed on the same principle as Snellen's Test Types. A useful and ready clinical method consists in gradually diminishing the illumination of the test-types and comparing the acuteness of vision of the patient with that of the surgeon, provided the latter have a normal light-sense. The L.D. is most affected in diseases of the optic nerve, and the L.M. in chorioido-retinal affections ; but the measurement of the foymer is not often required in clinical work. CHAP, i.l FUNCTIONAL EXAMINATION OF THE EYE, 11 Retinal Adaptation. — It is a common experience, on passing from daylight into a darkened room, to find that at first nothing is visible, but that after a time the various objects in the room begin to appear, until final y almost everything can be seen. This phenomenon is called " Adaptation " and is due to the fact that the retinal purple, which has been bleached by light, is only gradually regenerated. In testing the light-sense, therefore, it is necessary to allow some time for the eye to adapt itself. Complete adaptation is very slow, but for practical purposes 20 minutes may be deemed sufficient. Adaptation is slower at the macula lutea than ovitside it, probably because of the absence of rods, which alone contain the visual purple. In some diseases, such as retinitis pigmentosa, the power of adaptation is extremely slow and defective, and gives rise to night blindness. In- creased power of adaptation, curiously enough, is only met with in total colour-blindness. * The Colour-Sense is the power the eye has of distinguishing light of different wave-lengths. According to the Young-Helm- holtz theory, the retina possesses at least three sets of colour-per- ceiving elements, those for Red, Green, and Blue or Violet. These are termed primary colours because by their combination white light as well as all other colours can be produced. According to Hering's theory, the colour-sense and the light- sense depend upon chemical changes in the retina or in the visual substances contained in the retina. He suggests the existence of three different visual substances, the white-black, the red-green, and the blue-yellow, by the using up or Dissimilation, and restora- tion or Assimilation of which substances the sensations of light and colour are produced. These theories are not satisfactory, for they do not explain cases in which shortening of the spectrum occurs, and many other facts connected with colour-vision, and they are not founded on an anatomical basis. Hering's views are com- pletely disposed of by the discovery that the electrical reactions in the optic nerve, produced by stimulation of the retina by different colours, differ only in degree and not in kind. Edridge-Green's theory, which is the result of many years' study of the subject, is, that light falling upon the retina, liberates the visual purple from the rods, and a photograph is formed. The rods are concerned only with the formation and distribution of the visual purple, not with the conveyance of light impulses to the brain. The decomposition of the visual purple by light chemically stimulates the ends of the cones (very probably through the electricity 12 DISEASES OF THE EYE. [chap. i. which is produced), and a visual impulse is set up, which is con- veyed through the optic nerve-fibres to the brain. The character of the impulse set up differs according to the wave-length of the light causing it. Therefore in the impulse itself we have the physiological basis of the sensation of light, and in the quality of the impulse the physiological basis of the sensation of colour. Colour-vision, therefore, consists in the power of distinguishing between rays of different wave-length, and the greater the degree of development of the colour-perceiving centre in the brain, the more acute will be the power of distinguishing differences of wave-length, consequently the smaller will be the interval in the spectrum between the rays which are recognised as different, and therefore the more numerous will be the colours perceived. When the colour-perceiving centre is badly developed, the points of differ- ence will be greater, that is to say, the rays perceived as different will be farther apart in the spectrum, and the number of colours recognised fewer — in other words, there will be blindness for one or more colours. It may also happen that the visual purple is not acted upon by the rays at the extreme ends of the spectrum, and then the spectrum will appear shortened. According to this theory, therefore, the colour-blind are divided into two distinct classes independent of each other, but which may be associated. The first class includes those who see the spectrum shortened at the red or violet ends, or at both ; while in the second the number of colours visible in the spectrum is smaller than the normal. A consideration of the way in which the colour-per- ceiving centre develops, according to Edridge-Green, will help us to understand the various degrees of colour-blindness. At first no difference would be recognised, the whole spectrum would appear of a neutral colour. In the next stage only the extreme ends of the spectrum would be differentiated, namely, the red and violet, with a more or less wide neutral band of grey between them ; the grey band would gradually diminish until the two colours met ; following on this stage a third colour would appear at the next point of greatest difference, namely, at the centre of the spectrum in the green, and so, in order of succession, yellow, blue, and orange would be added. Thus, if the normal- CHAP. I.J FUNCTIONAL EXAMINATION OF THE EYE. 13 sighted be designated as liexacliromic (seeing six colours) ,i the colour- blind may be divided into the pentachromic (seeing five colours — red, yellow, green, blue, violet), the tetrachromic (seeing four — red, yellow, green, violet), the trichromic (seeing three — red, green, violet), the dichromic (seeing two — red and violet), and finally, the monochromic, or totally colour-blind. It must be remembered, however, that all grades of transition exist between total colour-blindness and a normal colour-sense, so that even in one class, say the dichromic, it is difficult to find two colour-blind persons who will behave exactly alike with all tests. Colour Tests. — Testing the colour-sense is by no means a simple matter. It requires a good deal of experience, as well as a know- ledge of colour-blindness and of the eye itself, to apply the tests in a really satisfactory way. It is advisable therefore that they should not be entrusted to laymen, or even scientists, but should be carried out by ophthalmologists. The spectrum affords the most accurate of all tests, but a special spectroscope is required, and, owing to the expense and expert knowledge necessary, as well as to the fact that a certain degree of intelligence on the part of the patient is required, it is hardly suitable for clinical use. It is now almost universally admitted that Holmgren's coloured wool test is inadequate as an efficient test. Edridge-Green uses two tests, a classification test and a lantern test. The Classification Test consists of a number of coloured beads in which every variety of confusion colour of the colour blind is well represented, and a box with four compartments into which the beads can be dropped. The aperture to each of the compart- ments is such that the observer cannot see the bead after it has been dropped into the box. The four compartments of the box are labelled Red, Yellow, Green and Blue. The examinee is told to, pick out from the beads in front of him, which are placed on the white porcelain lining of the box, all those that are red, keeping as nearly as possible to the exact hue, but selecting those that are lighter or darker of the same colour, and to drop them one by one into the compartment labelled Red. He then goes through the 1 In very rare cases a seventh colour, called ind'go, is seen in the spectrum. U DISEASES OF THE EYE. [chap. i. same process with the three other colours ; he is not allowed to compare the colours directly, but must select them entirely according to the name which he gives to the colour. It will be found that whilst the normal-sighted are able to select the correct colours with the greatest ease, the colour-blind will make their characteristic mistakes. This test, like the lantern, will detect cases of colour scotoma as well as those of ordinary colour-blindness. The Lantern Test, which is very efficient and practical, consists of a lantern with coloured glasses revolving behind a circular opening which can be altered in diameter. The colours can be shown separately or combined, and can be modified by neutral or ribbed glass, so as to represent signals as they are affected by distance? fog, or rain. It forms an ideal test for railway servants and sailors. The examinee is asked to name the colour of the light shown. The use of colour names is absolutely necessary, or normal-sighted persons will be rejected, through paying attention to shade rather than to colour. It does not matter what name is applied to a colour ; but ground for rejection is afforded when the examinee calls two of the main colours of the normal-sighted, as, for instance, red and green, by the same name. Since all grades of colour-blindness exist, the practical question therefore is to draw the line at which rejection should take place. The following should be rejected as being dangerously colour- blind : 1. Those who see only three colours (trichromics), or less than three. 2. Those who have a shortened red end in their spec- trum, even though they may be hexachromics. 3. Those affected with central scotoma for red or green. Stilling's test, in which spots of a given colour are printed on a background of a confusion colour, finds favour with some. Colour-blindness is either congenital or acquired. Congenital colour-blindness occurs in 3 '5 per cent, of men and less than 1 per cent, of women. It is hereditary, but is transmitted by females with normal colour sense. Acquired colour-blindness* is found in toxic amblyopia, in atrophy of the optic nerve, and in some other conditions. The Form-Sense (Acuteness of Vision). — By Acuteness of Vision (V) is meant the power which the eye, or rather the macula lutea, has of distinguishing form, any anomaly of its refraction, if such CHAP. I.] FUNCTIONAL EXAMINATION OF THE EYE. 15 exist, having been first corrected. In clinical ophthalmology the testing of this function is an important and ever-recurring duty. When applied to by a patient on account of imperfect sight it is our first duty, as a rule, to ascertain accurately the condition of refraction and accommodation of his eyes. Should these be abnormal, and it be found that by aid of the correcting glasses perfect vision is obtained, it may, in general, be concluded that the eye is organically sound, and that the patient's complaints are due to the defect in accommodation or refraction. If glasses do not Fig. 8. restore perfect vision, we must then, by the ophthalmoscope and other methods, decide the nature of the defect. Now, in order to measure the acuteness of vision we must have a normal standard for comparison — i.e., we must find what is the size of the smallest retinal image whose form can be distinguished. We cannot, of course, measure this image on the retina directly ; but, as its size is proportional to the visual angle — the angle which the object subtends at the eye — it is sufficient to determine the smallest visual angle under which the form of an object can be distinguished. It has been found, experimentally, that the average size of this angle is 5 minutes (Fig. 8).^ In order practically to ascertain the degree of acuteness of vision we place our patient with his back to the light, while facing him at a distance of 6 metres, and in good light, are placed Snellen's Test-Types for distance. These types are so designed that, at the distance at which they should be seen, they each subtend an angle ^ The minimum separabile or smallest angle under which two points can be distinguished is 1 minute, and corresponds approximately with the distance between three retinal cones, the central one not being stimulated. 16 DISEASES OF THE EYE. [cHAt. I. of 5' at the eye. The largest type should be seen at 60 metres (Fig. 8) by the normal eye, and the types range from this down to a size visible not farther off than 6 metres. If V=Acuteness of Vision, d = the distance from the eye to be tested to the test- types, and D = the distance at which the type should be distin- guishable, then V = ^. For example : if d = 6 metres (a distance which most rooms can command), and if the eye see type D = 6, then V = f = 1, or normal V. ; but if at 6 metres the eye see only D = 60, which should be seen at 60 metres, then V = -^^, in short V = 6 divided by the number of the type read. A distance of 6 metres is selected because the test-types are also used to test the refraction, and at that distance the rays proceeding from the type may be considered to be parallel. In practice these fractions must not be taken in a strict mathe- matical sense. For example, /^ does not mean that a patient with that degree of V has his visual capacities lessened by one-half. A series of types resembling the letter E, in various positions, is also used for testing illiterates. Or, better still, an incomplete circle like the letter C in different positions can be used, the patient being required to tell where the break in the circle is placed. This has lately been recommended as a universal test. The types of Jaeger for near vision are sometimes used for testing the acuteness of V. Should the patient's sight be so defective that he is unable to read any of the letters, it may be tested by finding at what distance he can count the surgeon's fingers ; and if he cannot even do that, then his power of perception of light (his P.L.) should be tested. This is done by means of a lamp in a dark room, the eye being alternately covered and uncovered, and the patient being required to say when it is " light " and when " dark." If the flame be gradually lowered the smallest degree of illumination perceptible will be ascertained. The eyes must be examined separately, that one not under examination being excluded from vision by being shaded with the patient's own hand or other suitable screen ; but it must not be at all pressed on, as ^ny pressure would dim its vision when its turn for examination may come. When a trial frame is put on, the patient should not be allowed to turn his face to one side, or else he may be with the eye which is covered. CHAP. I.] FUNCTIONAL EXAMINATION OF THE EYE. 17 With the advance of age the acuteness of vision undergoes a slight but steady reduction, owing to certain senile changes in the eye. THE FIELD OF VISION. By the Field of Vision (F.V.) is meant the space within which objects can be seen by one eye, the other being closed, the gaze of the former being fixed on some one object or point. Thus, if stand- ing on a hill, we fix the gaze of one eye on some object on the plain below, the field of vision includes not only that object, but many others also for miles around it. The fixation object is seen by central or direct vision, its image being formed on the macula lutea ; the other objects in the field of vision correspond with as many different points in the more peripheral parts of the retina, and are seen by eccentric, or indirect, vision. Eccentric vision is of great importance for guiding oneself and for the avoidance of obstacles. This may be realised by the ex- periment of looking through a long small-bore cylinder {e.g., a roll of music) with one eye, thus cutting off its eccentric field, while the other eye is closed. The Examination of the Field of Vision (Perimetry) is carried out for clinical purposes by means of an instrument called the peri meter. This is a semicircular arc of metal capable of revolving upon its middle point, so as to describe a hemisphere in space. The arc is divided into degrees from 0° at its middle point, to 90° at either extremity. At the centre of the hemisphere is situated the eye under examination, while the fixation point is placed exactly opposite, in the middle of the semicircle, at 0°. The test object, a small bit of white paper 5 or 10 mm. square, is slowly moved along the inner surface of the arc from the periphery towards the centre, until it comes into view, and the observation is repeated in various meridians. The horizontal, vertical, and two intermediate meridians, at least, should be examined by placing the arc of the perimeter in the corresponding planes. The patient's eye must be carefully watched, as any movement of it away from the fixation point would vitiate the results. The boundary of the field is noted on a diagram or chart (Fig. 9) , which represents the projection of a sphere on a plane surface. The radii represent different meridians, and are indicated by a 18 DISEASES OF THE EYE. [chap. i. dial with pointer on the back of the perimeter, while the concentric circles correspond with the degrees marked on the arc. A pencil mark is placed on the chart at the spot corresponding with that on the perimeter at which the test object comes into view ; and, when the different meridians have been examined, these marks are united by a continuous line, which then represents the outer boundary of the F.V. In some cases (hemianopsia, etc.) it is better to take Right Eye 80 tias. ^1 100 3^ 80 ^.20 40^ '"^ _70 ^7\" ^\40 /^ GO :3° — -^ 2^ ^v 60/ 5 ^ Xeo / />' y^X ^ \J0 7= :->^^Cn Sv\ r— A 7// Ml X 1 ~i w u\ 1 n 7I0 GO fi (M^ ^ ^ Y^f^ bjojep "1 aUp rV TV jm V- V xT ff\ //' \ ^ ^ \S \/ 720 ^ >yf y /2o\ 140^ 1 160 C n rSi ^>I40 ^20 ? ^ ^ — — ^ \^ 80 160 temp ISO Fig. 9. the field by the circular method, i.e., by placing the test object successively on the different degrees of the arc, and each time rotating the arc through a complete circle, the points or meridians at which the object appears and disappears from view being noted. The normal F.V. is not circular, but extends outwards about 95°, upwards about 53°, inwards about 47°, and downwards about 65°, as represented by the strong curve in Fig. 9. The limitation upwards and inwards is partly due to the projection of the supra- orbital margin and the bridge of the nose, but also to the fact that the outer and lower parts of the retina are less practised in seeing than are the upper and inner parts, and their functions consequently CHAP, i.j FUNCTIONAL EXAMINATION OF THE EYE. iw less developed. The acuteness of vision diminishes progressively towards the periphery of the field, two points of a certain size close together being distinguishable from each other only a short distance from the fixation point, while the farther towards the periphery the larger must be the test objects. Fig. 10 serves to illustrate the projection of the field of vision of the right eye on the semicircle of the perimeter to its extreme temporal (95°) and its extreme nasal (47°) boundaries, as well as the portion of the retina {a to b) which corresponds with this extent of field ; and it shows that the sensitive portion of the retina, or Fig. 10. rather perhaps the portion of the retina which is most used, ex- tends farther forward on the nasal than on the temporal side. The diagram also explains the remarkable fact that the field extends in the temporal direction more than 90°. The Blind Spot of Mariotte is a small blind island or scotoma in the F.V. It takes the shape of an oval with the long axis vertical, whose centre is situated about 15° to the outer side of the point of fixation and just below the horizontal meridian. It is shown as a dark spot in Fig. 9. It is due to the optic papilla (optic disc), for at that place the outer layers of the retina are wanting, and hence it possesses no power of perception. 20 DISEASES OF THJS EYE. [CHAt*. 1. For the detection of small defects such as enlargement of the blind spot and central scotomata in the early stage, it is necessary to employ Bjerrum's Method, in which the observations are made with a black (velvet) screen at a distance of 1 or 2 metres, using a very small test object, of 1 or 2 mm., or Priestley Smith's scotometer may be used. The field of vision when taken in this way is much smaller, and is approximately circular, measuring about 30°. An exact record, therefore, of a perimetric examination should give the size of the test object and its distance from the patient's eye ; these particulars are then entered as a fraction having the former as numerator and the latter as denominator. The presence of a gross alteration in the field may be roughly ascertained if the ob- server face the patient, who has his back to the light, and use his own hand as a test ob- ject. The eye of the observer which is oppo- site the patient's eye serves as a control, as its field can be tested at the same time as that of the patient's eye. In the Binocular Field of Vision, since the two visual lines meet at the fixation point, the central portion is common to both eyes (Fig. 11). * Pathological Defects in the Field of Vision.— As these are often of great diagnostic importance, it will be advisable to give a summary of the various types which are met with. Pathological alterations of the fields of vision may be divided into (1) Contractions of the field which begin at the periphery, (2) Insular defects, and (3) Loss of a half of the field, usually affecting both eyes and extending to the middle line. Contractions of the visual field may be {a) concentric as in atrophy of the optic nerve (Fig. 12), retinitis pigmentosa, and hys- FiG. 11. — Binocular Field of Vision. The white area is common to both eyes, P being the fixation point. The shaded portion on the right belongs to the right eye alone, while that on the left belongs to the left eye alone. Left Eye temp temp Fig. 12. — Extreme concentric^con- Fig. 13. — F.V. from case of Glaucoma, traction of F.V. in atrophy of the optic nerve. 160 '80 Fig. 14. — Sector defect in F.V. from branch embolism of the central artery of the retina. left Eye 160 '80 Fig. 1 5.— Sector-like defects in F.V. from case of disseminated sclerosis. 22 DISEASES OF THE EYE. [chap. terical amblyopia or (6) the defect may begin at a certain part of the periphery, as in glaucoma (Fig. 13), where the nasal side is the first to become affected, or as in detachment of the retina, when the portion of the field which is lost will depend on the position of the detachment. If this be below, as is most commonly the case, then the defect in the field will of course be above, (c) Sometimes the defect is irregular, or sector-like ; examples of this variety of field occur in embolism of a branch of the central artery of the retina (Fig. 14), and in some cases of atrophy of the optic nerve associated with tabes or multiple sclerosis (Fig. 15). An insular defect, which is termed a scotoma, may be central, ISO 180 Fig. l(i. — Central scotoma for red and green in toxic amblyopia. that is, involving the fixation point, or paracentral, in close proximity to it, or again it may be situated in any part of the remaining field. A central scotoma is an important symptom in toxic amblyopia (e.g. from Tobacco and Alcohol poisoning. Fig. 16) and in retrobulbar neuritis due to other causes, such as disease of the posterior nasal accessory sinuses. It sometimes makes its appearance in the very earliest stage of multiple sclerosis. In the cases just mentioned both eyes are affected, whereas the scotoma following on disease of the macula lutea is often unilateral. Non-central scotomata may arise from retinal haemorrhages (Fig. 17), intra-ocular tumours (Fig. 18), and disseminated chorioiditis. A peculiar form of scotoma is the annular or ring-scotoma which Lef) Eye lUyhtEyc Fig. 17. — Scotoma in the F.V. Fig. 18. — Large scotoma caused caused by a large retinal haemorrhage. by an intra-ocular sarcoma. Fig. 19. — Irregular annular scotoma due to specific chorioido-retinitis. 80 80] 7 r~7ioo 100 Fig. 20. — Bitemporal hemianopsia in a case of pituitary disease which proved fatal. 24 DISEASES OF THE EYE. [chap. i. surrounds the fixation point, without involving it. It is met with in retinitis pigmentosa and in syphilitic chorioido-retinitis (Fig. 19). ^ 3. Hemianopsia will be dealt with more particularly in chap. xiv. When the right or left halves of both fields are lost, the condition is termed Homonymous Hemianopsia. If both temporal halves are blind then we have a Bitemporal Hemianopsia. The commonest cause of the former is a haemorrhage in the mesial surface of the occipital lobe, and of the latter tumour of the pituitary body (Fig. 20). In some instances a quarter of the field only is lost in each eye ; but this is merely an incomplete form of hemianopsia. A defect in the field is Positive if it be visible to the patient as a dark area. Negative if it be invisible. If the blindness be complete, the defect is said to be Absolute ; but if the acuteness of vision be merely diminished, it is said to be Eelative. A relative defect may exist for colours only (Fig. 16), most commonly for red and green. In all eyes the blind spot is a negative and absolute scotoma in the field of vision. When the vision is too defective to permit of the field of vision being tested in the ordinary way, the patient may be asked to indicate the position of a light placed in different parts of the field ; this is called testing the Projection of Light. The Perception of Colours in the Periphery of the Field can be examined with the perimeter, by means of bits of coloured paper not more than 5 mm. square. It has been in this way ascertained that the boundaries of the power of eccentric perception for the different colours do not seem to correspond with the boundary for white light, nor do the boundaries of the different colours seem to incide. Examining from the periphery towards the centre by ordinary daylight, blue is the colour which can be distinguished as such most eccentrically, its field extending nearly as far as the general F.V. ; then come yellow, orange, red, and, with the most limited field, green. Blue, red, and green being the most important, their fields are noted in Fig. 9. Although the respective colours are distinguishable within the limits indicated, they are by no means so brilliant in hue as when seen by direct vision. It has, however, been demonstrated that every colour is recognisable up to the outer limit of the F.V., if the coloured object be of sufficient surface and be sufficiently illuminated; so that there is, in fact, no absolute CHAP. I.] FUNCTIONAL EXAMINATION OF THE EYE. 25 colour-blindness in the peripheral parts of the retina, but merely a diminished sensitiveness to coloured light. Pathological Changes in the Colour Fields need only be referred to briefly. The most important are : (1) The central scotoma for red and green which occur in toxic amblyopia (Fig. 16). (2) The concentric contraction of the colour fields in atrophy of the optic nerves, which often precedes the failure for white, and in the later stages progresses more rapidly, so that the field for colours is rela- tively more reduced in size than that for white. (3) A hemianopsia may also exist for colours only (see chap. xiii. part 1), to be followed later by loss of the half fields for white. (4) Finally the normal order of the boundaries of the fields for the different colours may be, to a certain extent, reversed, or instead of being concentric they may overlap. These conditions have been observed in cerebral tumours and in hysteria. That colour defects can exist alone, does not require the assump- tion of the existence of a separate cortical centre for colour vision ; indeed, facts seem rather to support the view that lesions of the visual nerve fibres interfere more easily with the transmission of those impulses which produce colour vision, than with those which cause the sensation of white. The Perception of Form in the Perifhery of the Field is very defective, and its examination is not of much practical importance ; but this portion of the field is very sensitive to the movement of objects. Enlargement of the Blind Spot occurs in cases of opaque nerve fibres, posterior staphyloma, and optic neuritis, but of late it has been pointed out that an increase in size of the blind spot for white or colours is one of the earliest signs of involvement of the optic nerve in disease of the posterior nasal accessory sinuses and appears before the central scotoma. Accord- ing to Van der Hoeve the blind spot measures on an average about 7° vertically, 5° horizontally, and is surrounded by a colour-blind area of less than 1°. CHAPTER II. THE OPHTHALMOSCOPE. Before proceeding to describe the ophthalmoscope, a brief statement of the properties of plane and concave reflecting surfaces (or mirrors) will be of use. Laws of Reflection. — When a ray of hght, O S (Fig, 21), meets a polished surface or mirror, M M, at a given point, S, the angle of incidence, i, formed with the perpendicular to the surface, P, is equal to the angle of reflection, r, and the incident and reflected rays O S, S R, lie in one plane. Images formed by a Plane Mirror. — To an observer placed at R the point O would seem to be at I, where the prolonga- tion of R S intersects the line I O per- pendicular to the mirror, and O M is equal to M I. Similarly the image of the point B is found on the perpendicular B E, E D being equal to D B. The image I E therefore, formed by a plane mirror, is virtual, erect, and situated behind the mirror &X the same distance from it as the object O B. Images formed by a Concave Mirror. — In Fig. 22, c is the centre of curva- ture of the mirror M M. The rays a, b, parallel to the axis S /, meet the surface of the mirror at M and M' and are reflected to F the principal focus. The angle of incidence a M c being equal to the angle of reflection F M c, the radius c M being perpendicular to the surface of the mirror at M, F lies midway between S and c ; that is to say, the focal length of a concave mirror is equal to half the radius. Rays from a point /, beyond c, are made to converge at /', between F and c, and the farther away / is the nearer will /' be to F ; / and /' are con- jugate foci. The conjugate focus of a point nearer the mirror than F would be virtual, because the rays then diverge after reflection. In ophthalmoscopic work the source of light is usually farther away than the centre of curvature of the mirror, and Fig. 23 shows how, in this case, a real inverted and diminished image of the light is formed. The image of the point O is found at I, the point of intersection of the ray 26 Fig. 21. — Reflection by a plane mirror. THE OPHTHALMOISCOPE. 27 O I, which passes through the centre of curvature C, without deviation, and the ray O S parallel to the axis, which passes through the principal focus F, after reflection ; the image of the point B is found in a similar manner. As O B ap- proaches C, I M also approaches it, and in- creases in size until at C object and image are of equal size and coincide. When the object lies between F and the mirror, a vir- tual, erect, magnified image is seen. A con- cave mirror therefore resembles a convex lens in its action (chap, xv., § 5.) Fig. 22. — Reflection by a concave mirror. To distinguish a Plane from a Concave Mirror the student should stand with his back to the source of light and, with the ophthal- moscope held in front of him and a little to one side, should throw the light reflected from it into his own eye ; he will then see an erect image, if the mirror be plane, or an inverted image, if the mirror be concave. A simpler method consists in facing the source of light, and throwing the reflected light on a screen, say the palm of the hand, and moving the mirror towards or away from it ; then, if the mirror be plane, a round image with a dark central spot will be formed at all distances ; but. if the mirror be concave, at a certain distance an inverted image of the source of light will be formed. The Ophthalmo- scope .—Although the dioptric media of an eye may be perfectly clear and normal, yet no de- tail of its fundus can be discerned by the unaided eye of an observer who looks through the pupil, the latter being for him merely a dark opening. The reason of this is, that light can only enter the eye through the pupil and the refractive media. In albinos the pupil appears red, because Fig. 23. — Image formed by a concave mirror when the object is beyond the centre of cur- vature. DISEASES OF THE EYE. [chap. II. the absence of the uveal pigment allows the light to penetrate the sclerotic and illumine all the interior of the eye in a diffuse manner. To explain : — Suppose the inside of a small box {vide Fig. 24) to be blackened, and on its floor some printed letters fastened, and a hole cut in the lid, which is then replaced — it will be found that, by aid Fig. 24. of a lighted candle and with a little experimentation, the letters may be read through the aperture. The rays passing from the light (L) into the box through the aperture illuminate the opposite surface, and from this surface the rays a. h, and others pass out again through the opening, and some of them fall into the observer's eye at E. But if, in order to make this box represent an eye, we place a convex lens, 71, of the proper strength, immediately within the aperture, all the rays passing into the box (Fig. 25) from L are brought to a focus on its opposite side at m by the convex lens n, Fig. 25. and, according to the law of conjugate foci (§ 17, chap. xv.). all the rays passing out from the box meet again at the source of light (L), and hence none of them can be received by the eye (a) of the observer ; nor can this eye be placed in any position where it could receive any of these rays, for if it be placed anywhere between the aperture and L, it would cut off the light passing from L into the box. CHAP. II.] THE OPHTHALMOSCOPE. '20 If the back of the box were further forward, the light would not be focussed on it, and the emergent rays would form parallel or conical divergent beams passing back to and surrounding L. In the latter case, if an observer held his eye close beside the light, some of the divergent rays would enter it, and the letters would be visible. This explains the red pupil often seen in hypermetropia and aphakia. Hehnholtz's Ophthalmosco'pe. — If the eye of the observer could itself be made the source of light, the difficulty would be solved ; and, practically, this is what Helmholtz accomplished with his ophthalmoscope in the year 1851. The instrument he invented Fig. 26. was composed of a number of small plates of glass {0, Fig. 26), from which light from L was reflected into the eye (E), and thus the fundus of the latter was illuminated. From m rays pass back again by the same path to the ophthalmoscope, some being reflected back to L ; but some, passing through the ophthalmoscope, and falling into the observer's eye placed close behind the instrument at a, form in it an image of m. Modern Ophthalmoscope. — For the original ophthalmoscope of Helmholtz a concave mirror of 20 cm. focal length with a central opening has been substituted. This mirror (0, Fig. 27) throws convergent rays into the eye {E) ; and these, being made more con- vergent by the refracting media, cross in the vitreous humour, and light up part {a b) of the fundus. From every point of this illumin- ated surface rays are reflected back again out of the eye. If the latter be emmetropic, the rays from any one point become parallel on leaving it ; and some of these parallel rays, passing through the aperture of the ophthalmoscope, fall into the observer's eye, and, if it be emmetropic, are brought to a focus on its retina ; the rays 30 DISEASES OF THE EYE. [chai'. it. from m at m\ those from a: at a;', and those from y at y' — and thus an image of the part x m y is formed on the observer's retina. Fig. 27. The foregoing method of examining with the ophthalmoscope is called the Direct Method, or the Examination of the Upright Image. The light should be placed on the same side as the eye to be examined, it should be on a level with the eye, and sufficiently behind the patient to leave the eye in the shade. The observer uses his left eye for the patient's left eye, and his right for the patient's right eye, and by a slight inclination of his head he can get very close to the patient's eye without coming into contact with his face. By this method the various parts of the fundus are seen in their natural positions, but much enlarged. The magnification is about 15 diameters in Em., more in M. and less in H. ; and it is consequently very valuable for examining minute details. The area visible at one moment is, however, small, not much larger than the optic disc. It is necessary that the observer should approach his eye as close as he can to the eye under examination, in order to receive as much of the light coming out of it as possible, and also to obtain the largest possible field. The extent of the area visible at one moment depends also on the refraction, being greatest in H., and least in M. Moreover, the accommodation both of the observer's and of the patient's eye must be at rest, as otherwise the rays coming from the latter cannot form an image on the retina of the former, at least if both be emmetropic. If the patient exert his accommoda- tion, the rays will, on leaving his eye, become convergent instead of parallel, and, falling into the observer's eye, will be brought to a focus in front of his retina. The same will happen if the observer OHAP. ii.l THE OPHTHALMOSCOPE. exert his accommodation, and still more so if both patient and observer accommodate. The patient's accommodation can be relaxed by making him gaze at the black wall behind the observer's head, or his accommodation may be paralysed with atropine. But atropine should never be used in adults unless absolutely necessary, owing to the inconvenience it causes the patient. Voluntary relaxation of the accommodation on the part of the observer is often a matter of much difficulty to beginners. With parallel optic axes our accommodation is relaxed ; therefore, when we want to relax our accommodation, we produce parallelism of our optic axes. . This sounds easy enough ; yet, when the beginner approaches his eye close up to that of his patient, the knowledge that he is so close to the object he wishes to see renders the accom- plishment of this parallelism and relaxation of accommodation very difficult to many. It can only be attained by practice, but it is assisted by the fact that the eye which is not in use gazes at the black wall behind the patient's head. A beginner will find a low concave lens behind the mirror of great assistance. Fig. 28. The Indirect Method, or the Examination of the Inverted Image, is employed in order to obtain a more general view of the fundus than the direct method admits of. In addition to the ophthalmoscope, a convex glass — the object lens — {I, Fig. 28) of about 14 D is here used. The latter is held at about its focal length from the eye {E) under examination, while the observer throws the light from the mirror through it into the eye. In passing through I the rays are made convergent, and this convergence is increased by the refracting media, so that the rays cross in the vitreous humour, and light up a portion of the fundus 32 DISEASES OF THE EYE. [chap. n. oculi. From any points {a and h) of this illuminated place pencils of rays pass out again from the eye, and, becoming parallel, pass through I and are united by it at a' h' ; and thus a real inverted image, magnified about 4 or 5 diameters, is formed of the part a b, which image may be seen by the observer whose eye is placed behind 0. In Em. the image will be formed at the principal focus of the object lens because the emerging rays are parallel, in H. it will be found farther away from the lens, and in M. nearer to the lens than in Em. The stronger the object lens (/) the more convergent will the rays from the examined eye be made ; and consequently the closer must a' h' be to each other, and the smaller and brighter must be the image formed. The weaker the object lens the larger and less brilliant is the image, and the less annoying to the observer are the reflexes from its surfaces. If the lens be held at its focal length from the cornea, and then withdrawn until its principal focus is farther from the eye than the anterior focus of the latter, the image will remain unaltered in size in Em., will increase in size in M., and diminish in H. In examining by the indirect method, the observer first places the upper edge of the ophthalmoscope to his right supra-orbital margin, and, taking care that he is looking through the central opening of the mirror, he reflects the light of the lamp into the patient's eye at a distance of about 50 cm. A red glare from the fundus, known as the " red reflex," will then be seen in the pupil. Keeping the pupil illuminated, the convex lens of 14 D, held between the forefinger and thumb of the observer's left hand, is brought up in front of the patient's eye, and kept there in the perpendicular position, the observer steadying his hand with the tip of the little finger on the patient's forehead. The object lens is now removed just far enough from the patient's eye to cause the margin of the pupil to disappear out of the observer's field of vision. The observer then ceases to look into the eye, and fixes his gaze on the object lens, when the inverted image of the fundus should at once be- come visible, if the observer accommodates for the proper distance — and will seem to be situated in the object lens, although it really is in the air somewhat this side of the lens. Beginners often fail to see the fundus clearly, because they do not accommodate sufficiently, and hence a low -{- lens placed behind the sight hole of the mirror helps to bring the image into focus. CHAP. II.] THE OPHTHALMOSCOPE. 33 If, as is usually the case, the ophthalmoscope be held in the right hand, it is better to place the light on the patient's left, whichever eye be examined, as the observer's left arm will not then interfere with the light when the lens is held up before the patient's eye. The diagram (Fig. 29) serves to illustrate the eifect of inversion of the image. The left eye is seen in the upright image at a, while the same eye is seen in the inverted image at h. In the diagram the two images are of the same size for the sake of convenience ; although, of course, in reality the upright image is much larger Fig. 29. than the inverted image. Moreover, it should not be supposed that nearly the whole fundus oculi, as here represented, can be taken in at one view with the ophthalmoscope. The portion visible with the ophthalmoscope at one moment, even in the inverted image, is small ; so that it is necessary to examine the different regions in detail, in order to become acquainted with the condition of the whole of the fundus. The reflex from the surface of the cornea gives a good deal of annoyance to every beginner. It cannot be done away with, but is considerably diminished by holding the object lens farther from the cornea than the focal length of the lens ; and, as it moves in the opposite direction to a motion of the object lens, it is possible to see past it. Reflexless ophthalmoscopes which get rid of the corneal reflex by making use of different portions of the patient's pupil for the entering and emergent rays have been designed by Thorner, and by Gullstrand. In Gullstrand's method of ophthalmoscopy a Nernst lamp with a fine vertical slit acts as the source of light. It ensures a brilliant illumination and shows up fine details with great definition. 3 34 DISEASES OF THE EYE. [chap. n. The reflections from the convex object-lens are also extremely annoying, but may be removed to a great extent from the line of sight by a slight rotation of the lens on its axis. If a very high object-lens (say + 20 D) be used, the reflections from it are more disturbing than from a lower number (say + 14 D). To examine the Opic Nerve (or Optic Disc) the observer sits in front of the patient, and directs him to turn his eye somewhat to the nasal side, and slightly upwards ; because the optic nerves, diverging from the chiasma, enter the back of the eye a little to the inner side of the posterior pole, and the papilla, or disc, comes to be situated about 15° to the inner side of the posterior pole of the eye, and about 3° above it. For instance, if the left eye be examined the patient is to direct his gaze, (without turning his head,) to his right and a little upwards, say towards the observer's left ear. It is well always to seek out the optic papilla in the first instance, not only because it is such an important part of the fundus oculi, but also because, examining from it towards the periphery, we are the better able to determine the locality of any pathological alter- ation. Should the patient not direct his gaze in such a way as to enable the observer to see the optic disc or other desired region, it may be brought into view either by a motion of the observer's head in the opposite direction, or by a motion of the object-lens in the same direction, or by a combination of these measures. When the disc is opposite the observer's eye, the pupillary reflex is seen to become paler or even white, and the corneal image of the light will occupy the junction of the middle and outer thirds of the horizontal dia- meter of the cornea. The Macula Lutea should then be examined. It may be seen by directing the patient to look straight at the hole of the ophthal- moscopic mirror, for it will then correspond with the macula lutea of the observer's eye. It is more readily seen in the inverted than in the upright image ; but its examination is often very difficult, owing to contraction of the pupil produced by the strong light falling on so sensitive a portion of the retina, and by the reflections from the surfaces of the cornea and crystalline lens, which fill the area of this contracted pupil. It is therefore a better plan to direct the patient to look somewhat to the side of the eye under examination — e.g., to the right side of the observer's forehead, if the left eye THE OPHTHALMOSCOPE. 35 be under examination, and then by motions of the object-lens to bring the macula lutea into view. After this the Periphery of the Fundus in every direction is to be examined by making the patient look upwards, downwards, to the right, to the left, etc. The indirect method possesses the following advantages : — It gives a large field in which it is possible rapidly to locate the position of a lesion, it can be used no .matter what the error of refraction may be, and it is not necessary to approach close to the patient's face. Detection of Opacities in the Refractive Media by the Ophthal- moscope. — Opacities in the refractive media can be best detected with the ophthalmoscope by the direct method. All opacities look black in the red pupil, because they intercept the light returning from the illuminated fundus. Fig. 30. — Apparent position in the pupil of opacities of the media when the obser\^er alters his point of view. Two methods of examination are employed. In the first the eye is examined at a distance of about 30 cm. ; and the patient is directed to move the eye in different directions, in order to bring any peripheral opacities into view and also to localise them. Movable opacities must lie in the fluid media. They are almost always in the vitreous humour, and can be seen to float to and fro when the eye comes to rest. Fixed opacities move with the eye, and lie in the cornea or lens, or sometimes in the vitreous. Fig. 30 illustrates the apparent displacement of an opacity in the pupil according to its position in the media. When the eye of the observer is opposite the pupil, the opacities 1 to 4 lying on the axis appear as one point in the centre of the patient's pupil (shown by P). When 36 DISEASES OF THE EYE. [chap. ii. the eye is rotated upwards, or the observer moves downwards, 2, which is on the anterior surface of the lens, in the plane of the pupil, will still appear to be in the same position, while 1, seen in the direction a b, will seem to be displaced upwards, and 3 and 4 down- wards, the relative positions being as indicated in the circle at P'. The second and more delicate method of detecting opacities consists in examining the eye close up with a convex lens of 20 D, behind the sight hole of the mirror. Very fine opacities can be seen in this way, such as minute punctate deposits on the cornea. Focussing for different levels can be accomplished by approaching closer for deeper opacities, or by using gradually weaker lenses. Too strong an illumination interferes with the perception of faint opacities, hence the plane mirror serves better for this purpose than the concave. Prominent portions of the interior of the eye, such as a detached retina or an intra-ocular tumour, can also be detected, and examined in detail, by the direct method at a distance, or close up. The estimation of the refraction by the ophthalmoscope will be dealt with in chap. xvi. The electric ophthalmoscope, in which a small electric bulb acts as the source of light, is a very useful instrument, especially in the examination by the erect image. The Marple-Morton model, which has a U shaped mirror, is the best. In its most recent form the current is supplied by a small dry cell contained in the handle of the ophthalmoscope, which is also provided with a rheostat for varying the degree of illumination. THE NORMAL FUNDUS OCULI AS SEEN WITH THE OPHTHALMOSCOPE. The Optic Disc or Optic Papilla. — This is the first object to be sought for by the observer. It presents the appearance of a pale pink disc, somewhat oval in shape, its long axis being vertical. Occasionally the long axis lies horizontally, and sometimes the papilla is circular. The papilla is generally surrounded by a white ring, more or less complete, called the sclerotic ring, and often, out- side this again, by a more or less complete black line, the chorioidal ring (Plate I. Fig. 1). The sclerotic ring is due to the chorioidal margin not coming quite up to the margin of the papilla, the fora- men in the chorioid for the passage of the optic nerve fibres being somewhat larger than that in the sclerotic, and consequently a # PLATE I {To face page 36) Yjg. 1. — The optic disc shows a small central physiological cup, a pale scleral ring, and an outer pigmented or chorioidal ring. Close to the latter is a cilio-retinal vessel. The macula lutea, of a deeper red than the rest of the fundus, is surrounded by a delicate oval light- reflex. The bright spot in the centre of the macula is the fovea centralis. YiQ. 2. — The patch of opaque nerve-fibres is of a brilliant white ; it is prolonged in the direction of some of the vessels, and presents a characteristic finely striated border. Note the dark colour of the disc, which is chiefly a result of contrast. The vision was the same as in the unaffected eye. Plate I. Fig. 1. Normal Disc and Macula. L.W. Fig. 2. Opaque Nerve Fibres. CHAP. II.] THE OPHTHALMOSCOPE. 37 narrow edging of the white sclerotic is exposed. The chorioidal ring is the result of a hyper-development of pigment at the margin of the chorioidal foramen. The complexion of the optic disc results from the pink hue derived from its fine capillary vessels, combined with the whiteness of the lamina cribrosa, and the bluish shade of the nerve fibres. It is frequently not equal all over, but is paler on the outer side, where the margin is more defined, and where the nerve fibres are fewer than on the inner side. The apparent colour of the papilla depends also upon the complexion of the rest of the fundus. If the latter be highly pigmented, the papilla appears pale in contrast ; while, if there be but little pigment in the chorioid, the papilla may appear very pink. The complexion of every normal papilla is not identical, and care must be taken not to make the diagnosis " Hyperaemia of the papilla " where merely a high physiological complexion is present. The upper and lower margins of the papilla are often, especially in young people, a little indistinct, and show a delicate striation by the direct method of examination. This may be greatly exaggerated in hypermetropes, and has in them been sometimes erroneously taken for optic neuritis. A physiological excavation of the optic papilla is often met with as a white depressed area (Plate I. Fig. 1) either on the temporal side or in the centre of the papilla, and can be recognised by the parallax 1 which may be produced, and by its colour. When the excavation is very deep, one may sometimes observe the lamina cribrosa in the form of grey spots (the nerve fibres) surrounded by white lines (the fibrous tissue of the lamina). A physiological excavation differs from a pathological excavation, in that it does not reach the margin of the papilla all round. It is caused by the crowding over of the nerve fibres to the inner side of the papilla. Yet sometimes, a healthy optic papilla will be met with, in which the excavation apparently reaches the margin all round. The Normal Retina is so translucent that it cannot be seen, the red reflex being due to the chorioidal vessels. At most, a shim- mering reflection of shot-silk appearance is obtained from it, par- ticularly about the region of the yellow spot (Plate I. Fig. 1) and ^ For explanation of the parallax see chap. ix. 38 DISEASES OF THE EYE, [chap. n. along the vessels, but also towards the equator of the eye, and especially in dark eyes, and in young people. A peculiar, but physiological, appearance known as opaque nerve fibres (Plate I. Fig. 2) is occasionally seen. It is produced by some of the nerve fibres forming the internal layer of the retina regaining the medullary sheath on the distal aspect of the lamina cribrosa, or near the margin of the papilla, which they had lost in the optic nerve just before entering the lamina cribrosa ; the rule being that the nerve fibres lose their medullary sheath at the latter place definitely, and enter the retina as axis cylinders only, and hence are quite translucent. But in these cases the nerve fibres reflect the light strongly, giving the effect of an intensely white patch, com- mencing at the disc, extending more or less into the surrounding retina, and terminating in a brushlike extremity. In such cases the optic papilla appears to be darker than normal, partly from contrast. This appearance is constant in the rabbit's eye. The Macula Lutea is generally seen as a bright oval ring with its long axis horizontal, this ring being probably a reflex from the surface of the retina (Plate I. Fig. 1). It is remarkable that this halo is not visible with the direct method of examination — a fact due probably to the illumination being much weaker than with the indirect method. The area inside the ring is of a deeper red than the rest of the fundus, and at its very centre there is an intensely bright point, the fovea centralis. The ring is not seen in old people. The macula lutea is situated to the temporal side of the optic disc, about two disc diameters away from it, and slightly above the lower margin of the disc. The General Fundus Oculi surrounding the optic papilla and macula lutea varies a good deal in appearance, according to the amount of pigment contained in the chorioid and in the pigment- epithelium layer of the retina. 1. If there be an abundant supply of pigment in each of these positions, the chorioidal vessels are greatly hidden from view, and the effect is that of a very dark red fundus. 2. If there be but little pigment in the pigment-epithelium layer, the larger chorioidal vessels may be visible, and the fundus may appear to be divided up into dark islands surrounded by red lines. 3. If the individual be a blonde, there is little pigment either in the pigment-epithelium layer or in the chorioid, and the fundus is seen of a, very l)right red colour, the chorioidal vessels down CHAP. II.] THE OPHTHALMOSCOPE. 39 to their fine ramifications being discernible. In albinos even the chorioidal capillaries may be seen. The chorioidal vessels are flat, they vary much in size, and anastomose freely (see Plate IV. Fig. 1, and Plate IX. Fig. 2). The Retinal Vessels. — The arteries are recognised as thin bright red lines running a rather straight course, in the centre of each of which is a light-streak. As to the cause of this light-streak there is considerable divergence of opinion. Some attribute it to reflection Fig. 31. {Groefe and Scemisch.) a.n.s., Art. nas. sup. ; aji.i., Art. nas. inf. ; a.t.s., a.t.i., A. temp. sup. and inf. ; v.n.s., v.n.i. Ven. nas. sup. and inf. ; v.t.s.,v.t.i.,\en. temp. sup. and inf. ; a.m.c.,v.m.e.,^^vt. and ven. median a.m., v.ni.. Art. and ven. macularis. from the coats of the vessel, or from the surface of the blood column ; while others believe that the light is reflected from the fundus through the vessel, which then acts as a very strong cylindrical lens. This light-streak divides the vessel into two red lines. The vems are darker, wider, and more tortuous in their course than the arteries, and, their coats not being so tense, the light-streak on them is very much fainter. 40 DISEASES OF THE EYE. [chap. ii. On reaching the level of the nerve-fibre layer of the retina the central artery and vein divide into a principal upper and lower branch. This first branching often takes place earlier in the vein than in the artery, and the former may even branch before appearing on the papilla, as in Fig. 31. The second branching may take place in the nerve itself ; and when this occurs it will appear as though four arteries and four veins sprang from the optic papilla ; but more usually this branching occurs on the papilla, as in Fig. 31. The vessels produced by this second branching pass respectively towards the median and temporal side of the retina, and are termed the Art. and Ven. nasalis and temporalis sup. and inf. {vide Fig. 31). The temporal branches run in a radial direction towards the anterior part of the retina. A small horizontal branch, the Art. and Ven. mediana, from the first principal branches is found passing towards the nasal side of the retina. The temporal branches do not run in a horizontal direction, but make a detour round the macula lutea, sending fine branches towards the latter. Two or three minute vessels from principal branches run directly from the papilla toward the macula lutea, and around the macula lutea a circle of very fine capillary vessels is formed which cannot be distinguished with the ophthalmoscope ; but no vessels run to, or cross over, the fovea centralis itself. The retinal arteries do not anastomose, nor do the larger retinal veins. The small retinal veins have some slight anastomoses near the ora serrata. Occasionally, a vessel emerges near the margin of the disc, usually at the temporal side. It arises from the ciliary vessels, and is hence called a cilio-retinal vessel (Plate I. Fig. 1). No pulsation of the arteries is observable in the normal eye. In the larger veins near or on the optic papilla, or more usually just at their point of exit, a pulsation may sometimes be seen. This venous puliation is due to the following sequence of events ; systole of the heart ; diastole of, and high tension in, the retinal arteries ; consequent increased pressure in the vitreous humour ; communication of this to the outside of the walls of the retinal veins, impeding the flow of blood through them, especially in their larger trunks, which offer little resistance, or at their exit from the eye, where the blood pressure is lowest ; and in this way the veins are emptied — the blood gradually coming on from the capillaries overcomes the resistance, and the veins are for a moment refilled. CHAP. II.] THE OPHTHALMOSCOPE. 41 The phenomenon can be most readily observed, if the normal tension of the globe be increased by gentle pressure with the finger during the ophthalmoscopic examination. By increasing the pressure the arteries also can be made to pulsate even in a normal eye, but such a degree of pressure is dangerous. CHAPTER III. DISEASES OF THE CONJUNCTIVA. The Conjunctiva, or Conjunctival Sac, whicli is a mucous membrane, may for descriptive purposes be divided into three portions : the palpebral, which forms a smooth lining for the inner surface of the eyelids ; the bulbar, loosely covering the sclerotic ; and the retro- tarsal folds, uniting ^these two, which form the sulcus or fornix, upper and lower. When the bulbar conjunctiva reaches the margin of the cornea it overlaps the latter sHghtly, and this overlapping portion is known as the limbus conjunctivae, or cornese. At the inner angle or canthus there is a vertical crescentic fold, the plica semi- lunaris, on the nasal side of which is a rounded mass of modified skin called the caruncle. On the palpebral surface of the upper lid close to, and running parallel to the margin, is a shallow groove, called the subtarsal sulcus. Some adenoid tissue exists in the fornices of the normal conjunctiva, and follicles are sometimes found, the latter being probably due to the constant irritation to which the conjunctiva is exposed. The conjunctiva is lubricated by the secretion from the glands and conjunctival epithelium. The lacrimal fluid, which has only a very slight bactericidal action, merely exercises a mechanical effect which consists in the washing away of foreign particles. The Examination of the Conjunctiva.— Simple inspection in good diffused daylight, the patient facing the window, is better than artificial illumination. The whole of the mucous membrane should be examined, and for this purpose the lids must be everted. The eversion of the lower lid is a simple matter, but a certain amount of practice is required in the case of the upper lid. Eversio7i of the upper lid. — The surgeon should face the patient and direct him to look down and to continue looking down, in order to render the upper edge of the tarsus accessible. The point of 42 CHAP. III. THE CONJUNCTIVA. 43 the thumb of one hand is then placed on the outer surface of the lid, just above the tarsus, and with it the skin is drawn a little Fig. 32. — First steps in eversion of upper lid. Fici. 33. — Everted lids held in position with one hand. upwards and backwards ; this causes the margin of the lid to start forwards. The eyelashes (or the margin of the Hd) are then taken between the thumb and forefinger of the other hand (Fig. 32) and Fig. 34. — Method of examining a child's eye. raised upwards, while the thumb above is depressed. The thumb which acts as the depressor should not be taken away too soon, a mistake often made by beginners, and it is better to slide it away 44 DISEASES OF THE EYE. [chap. III. sideways. In case of failure a probe or glass rod can be used instead of the thumb. When everted, the lids can be retained in position by one hand (Fig. 33), while ap- plications are being made to the conjunctiva. The method of examining the con- junctiva and cornea in infants and children is shown in Fig. 34. The head is firmly held between the surgeon's knees. The conjunctiva is easily inspected, as the lids be- come everted on merely attempting to open the eye by pulling on the skin near the lid margins. In order to examine the cornea, the lids must not be allowed to become everted, but must be separated with the points of the fingers placed on the ciliary margins as shown in Fig. 35. The cornea at first rotates under the upper lid, but soon comes down into view. Care must be taken to avoid injuring the cornea with the finger nails, or using too great pressure on the eye, which might rupture a corneal ulcer. The surgeon too must beware lest retained secretion should spurt up into his own eyes. The normal conjunctival surface of the upper lid is smooth. Fig. 35.— Method of exposing a child's eye. Fig. 36. — Examination of retro- tarsal folds of upper lid. Fig. 37. — Exposure of upper fornix ; lid everted and raised with retractor. yellowish-pink in colour, and the conjunctiva is adherent to the tai'siis The small l)i'anches of the tarsal arches can be seen runninjj; Plate II. Fig. I. Conjunctival Congestion. Fig. 2. Ciliary Congestion (Iritis). Fig. 3. Ciliary Congestion (Phlyctenular). Pig, 4. Ciliary Congestion (Glaucoma). Fig. o. Congestion in Scleritis. Fio. 0. Ecchymosis of Conjunctiva. PLATE II (To face page 4.1) TYPES OF CONGESTION Fig. 1. — Conjunctival congestion associated with catarrhal conjunctivitis. The vessels are bright red, tortuous, and easily seeii. The congestion is greatest towards the periphery. Fig, 2. — The delicate pink zone of ciliary congestion immediately sur- rounds the cornea, and is composed of very minute vessels which are not easily seen separately. A pointed posterior synechia renders the pupil irregular, and on the iris is a reddish yellow tumour (a gumma). Fig. 3. — These small patches of ciliary congestion precede or follow the development of marginal phlyctens. Fig. 4. — The ciliary congestion here consists of a fine venous reticulum. Note the few large tortuous veins, and the dilated and greenish pupil. Fig. 5. — Note the patch of deep violet congestion, with slight diffuse swelling, the discoloration of the sclerotic above and below, and the irregular outline of the cornea due to the encroachment of ' sclero- tising opacities.' Fig. C. — The appearance of the effusion of blood under the conjunctiva is easily distinguished from a localised congestion. ■■•■■-.;!• >■ : I" IM lilUi, ■ ' oi 9ub aenioo edi lo CHAP, iii.l THE CONJUNCTIVA. 45 in a vertical direction, and the Meibomian glands appear as yellowish or grey lines at right angles to the ciliary margin of the lid. The stndent should note the appearance and thickness of the edge of the normal tarsus when everted. Figs. 36 and 37 illustrate the method of inspecting the retro-tarsal folds and fornix. The double eversion (Fig. 37) is necessary in cases of suspected foreign bodies in the fornix. The blood-vessels of the conjunctiva consist of the posterior conjunctival vessels derived from the palpebral vessels, and the anterior conjunctival vessels which pass backwards from the anterior ciliary vessels. In general affections of the conjunctiva the former are chiefly involved. Engorgement of the vessels of the conjunc- tiva is known as conjunctival congestion (Plate II. Fig. 1), in order to distinguish it from ciliary congestion, which accompanies diseases of the cornea and iris. It is bright red in colour, most marked towards the fornix, and is formed by a network of large, tortuous, superficial vessels, which move with the conjunctiva. Ciliary con- gestion (Plate II. Fig. 2) on the other hand is limited to the cir- cumcorneal area, and diminishes towards the periphery. It is due to engorgement of the episcleral branches of the anterior ciliary vessels. It is pink or violet in colour, and is composed of minute straight radiating vessels, which are frequently indistinguishable to the naked eye as separate vessels. They are situated under the conjunctiva, and cannot be moved with it. In severe inflammations of the eyeball, such as a purulent ulcer of the cornea, these two forms of congestion are frequently present together. Hyperaemia of the Conjunctiva.— In this condition the blood- vessels of the palpebral conjunctiva are especially engaged. A slight serous exudation sometimes takes place, which may raise the conjunctiva around the cornea, a condition known as chemosis {xatiw, to gape open). Yet there is not any abnormal discharge from the conjunctiva, and herein lies the chief clinical difference between this affection and simple conjunctivitis. Of course a hyperaemia may be the earliest stage of a conjunctival in- flammation. Causes. — Foreign bodies. Dust, foul air, or air loaded with tobacco-smoke. Alcoholic excesses. Accommodative asthenopia. Stenosis lacrimalis, and other forms of lacrimal obstruction. The use of unsuitable spectacles, or the use of the eyes for near work 46 DISEASES OF THE EYE. [chap. m. without spectacles, "wlien the conditiou of the accommodation {e.g. hypermetropia, presbyopia) requires them. Symptoms. — Tlie eyes are irritable. There is lacrimation and photophobia, with hot, burning sensations, and sensations as of a foreign body in the eye, and the eyelids feel heavy. All these symptoms are aggravated in artificial light. Treatmeyit. — In addition to the removal of the cause, the in- stillation of mild astringents or of a drop of tincture of opium and distilled water in equal parts morning and evening will be found beneficial. Adrenaline has no permanent effect on the hypersemia. The eyes should be protected from the glare of light by dark glasses, and out-of-door exercise is to be recommended. Conjunctivitis in general. — The term Ophthalmia is commonly used as a synonym of Conjunctivitis, ^ which differs from mere hypersemia in the presence of abnormal secretion. Apart from mechanical or chemical irritation, inflammation of the conjunctiva is almost always caused by micro-organisms gaining access to the conjunctival sac ; or perhaps, in some cases, by the sudden develop- ment, under favourable conditions, of those which had been already present in a latent condition. They can easily be detected in the discharge, except sometimes in the rare cases of metastatic or endo- genous origin, and are the cause of its infectious nature. Sporadic cases are very common, but the disease frequently spreads through the members of a household, or occurs as an epidemic. Infection takes place by the direct transference of the secretion from person to person, or indirectly by a common use of the same articles by different people. Inflammations of the conjunctiva are met with in patients of all ages, and at all seasons of the year ; but some forms are more common in the spring and autumn. The palpebral conjunctiva is often affected when the bulbar portion remains normal, and the conjunctiva of the lower lid is more frequently attacked than that of the upper lid. Differential Diagnosis. — The milder forms of conjunctivitis are apt to be mistaken, by those who are inexperienced, for iritis and vice versa, but with care there should be no difficulty in distinguish- 1 Blepharitis is sometimes called Ophthalmia tarsi, and to this there can be little objection, but the name Sympathetic Ophthalmia is liable to mislead, as this disease has nothing to do with the conjunctiva, being in fact an inflammation of the uveal tract. OHAP. TIT.] THE CONJUNCTIVA. 47 ing between the two affections. Conjunctivitis is accompanied by conjunctival congestion, the secretion is muco-purulent, and if not in sufficient quantity to be detected in the conjunctival sac, its presence is indicated by the fact that the Hds are gummed to- gether in the mornings. The pain is superficial and limited to the eye itself (sensation of foreign body, heat, itching). Vision is not aflfected, except temporarily by secretion on the surface of the cornea, which is easily removed by rubbing the lids over the eye. Iritis, on the other hand, is recognised by the presence of ciliary congestion, lacrimation instead of a sticky secretion, and by the character of the pain, which is neuralgic and circumorbital. More- over, the vision becomes impaired at a very early stage of the disease. The ultimate diagnosis rests of course on the appearance of the iris and on the effect of atropine (see chap. vii.). Varieties of Conjunctivitis. — Although an accurate diagnosis of the different forms of conjunctivitis depends on the discovery of the particular micro-organism in each case, nevertheless the usual classification, which is based on clinical appearances, must for the present be adhered to, partly because these appearances are suffi- cient in most cases to indicate the line of treatment required, but chiefly because the type of inflammation excited by a given microbe is not sufficiently constant. In the majority of cases no doubt a definite group of symptoms is associated with a particular micro- organism, but occasionally the reaction takes a different form.^ Again, one and the same clinical picture may be produced by different micro-organisms. In exceptional cases, too, a mixed infection may take place. From a clinical point of view, then, conjunctivitis is divided into different varieties, depending on the nature of the discharge, the pathological changes in the tissues, and the severity of the symptoms. In Catarrhal Conjunctivitis, which may be acute or chronic, the discharge is muco-purulent in character, whereas in Purulent Conjunctivitis pure pus is secreted. The discharge becomes fibrinous and coagulates to form a membrane, lying on the surface of the conjunctiva, in the so-called Croupous variety, or it extends into the substance of the tissues in the Diphtheritic form. In some ^ This may be due to altered conditions, such as differences in the resistance of the tissues or blood, or to variations in the degree of virulence of the microbe. 48 DISEASES OF THE EYE. [chap. hi. cases (Spring Catarrh) the discliarge contains kirge numbers of eosinopliil cells. All inflammations of the conjunctiva are accom- panied by more or less increase of the normal lymphoid tissue, which is of a diffuse character, l)ut in certain cases lymphoid masses are formed which become visible to the naked eye, as in Follicular and Granular Ophthalmia. In Phh/ctenular Conjunctivitis small papules, or pseudo-vesicles, are found on the bulbar conjunctiva. Severe cases of conjunctivitis are often attended with slight swelling of the preauricular gland ; but in the condition known as ParinaucVs Conjunctivitis the glandular enlargement is considerable, and reddish ^vegetations form on the palpebral conjunctiva. Traumatic Con- junctivitis may be produced by physical or chemical causes, and inflammation of the lacrimal sac frequently extends to the conjunc- tiva. In rare cases a Metastatic Conjunctivitis due to endogenous infection has been observed. Finally Eczema, Impetigo, and some of the exanthemata (Measles, Scarlatina, Small-Pox) are frequently accompanied by conjunctivitis. The Bacteriology of Conjunctivitis. — The micro-organisms which are commonly met with as the active causes of conjunctivitis are not very numerous. The following is a list of them, with the clinical type of disease to which each most frequently gives rise : — Bacilli. The Koch-Weeks B. — (Acute Contagious Conjunctivitis). The Diplobacillus of Morax — (Subacute Angular C). The Diphtheria B.— (Membranous C). Cocci. The Gonococcus. — (Purulent C). The Pneumococcus. — (Cat- arrhal C). Streptococcus. Staphylococcus albus et aureus. The last two most frequently occur as part of a mixed infection, along w4th the gonococcus and the diphtheria bacillus. They are, however, also found, alone or together, in the conjunctivitis (often membranous) which accompanies impetigo of the face, or which follows scarlatina, but they have never been known to cause an epidemic. The Xerosis Bacillus (see Xerosis), which is non-pathogenic, is very frequently present in the normal conjunctiva and in the rnAP. III.] THE CONJUNCTIVA. 40 Meibomian secretion ; but it should also be remembered that some of the pathogenic forms, such as the staphylococcus, pneumococcus, and, it is stated by some, the streptococcus, are also found (especially the first named) in conjunctival sacs devoid of all signs of irritation. In fact the normal conjunctiva is rarely free from micro-organisms, and the results obtained by cultures may vary from day to day. According to Mayou there are fewer micro-organisms in the upper fornix than in the lower. The epithelium of the conjunctiva offers a certain resistance to the entrance of organisms, and hence many of them will not set up an inflammation unless there be a superficial loss of substance. All the above, with the exception of the gonococcus, the Weeks bacillus, and the diplobacillus, stain by Gram's method.^ The number of micro-organisms does not always correspond with the amount of discharge, and in some instances none can be found. We have recently had a case of this kind in which, although the discharge was profuse, both cover-glass preparations and at- tempts to obtain cultures gave negative results on three different occasions. The etiology of such cases is unknown ; they may perhaps be due to toxins circulating in the blood or to organisms as yet undiscovered. In addition to those which have been mentioned, other micro- organisms have occasionally been found in conjunctivitis. In the case of some of them it is very doubtful if they were the exciting cause of the condition of the conjunctiva w4th which they were associated. The most important varieties will be briefly referred to as we proceed. Catarrhal, or Simple Acute, or Muco-purulent Conjunctivitis.— In mild cases the affection is confined to the palpebral conjunctiva, often even to the conjunctiva of the lower lid ; but in the severer cases it extends to the bulbar conjunctiva. In the latter event the lids may be slightly hyperaemic and swollen. Both eyes are usually affected, either simultaneously or at a short interval. Lymph follicles and enlarged papillae are sometimes present. There 1 For clinical work, in most cases, cover-glass smears stained by Gram's method, followed by a counter-stain, such as weak Carbol-Fvichsin, or Loeffler's ^Methylene Blue, will suffice, but in some cases the identity of the particular microbe can only be established by cultures and inoculation experiments. 4 60 DISEASES OF THE EYE. [chap. hi. is a sticky, thin, mucous, or muco-purulent secretion which is often visible in the form of strings in the lower fornix. It dries on the eyelids at night so as to fasten them together when the patient awakes in the morning, and sometimes produces ulceration of the intermarginal portion of the eyelids (intermarginal blepharitis). In some of the very mildest cases this stickiness, or gumming, on awaking in the morning is a valuable diagnostic sign, for in such cases it is difficult or impossible to recognise by inspection the very slight variation from the healthy appearance of the conjunctiva. In the severer cases the papillae are markedly swollen, and may even conceal the Meibomian glands from view. Also, one often sees small ecchymoses in the bulbar conjunctiva, especially in certain epidemics ; but these have no serious import. Minute grey infiltrations which may break down and form small ulcers sometimes appear at the margin of the cornea, more especi- ally in old people. When there are many of them they may become confluent and form a small grey crescent, which ulcerates, and thus a crescentic marginal ulcer is formed, and very occasionally such an ulcer is followed by iritis. The catarrh may become chronic (p. 56). The chronic form of the disease is much less contagious than the acute, which frequently affects a whole family or may result in an epidemic. The Symptoms are those of a severe case of hyperaemia (sensa- tions of sand in the eye ; hot, burning sensations ; weight of the eyelid), with the addition of the annoyance consequent on the secretion, which, by coming across the cornea, may cause momentary clouding of sight. Photophobia is not generally severe unless there be some corneal complication. The symptoms are worse at night, or by artificial light, and are much less troublesome when the eyes are exposed to the open air. Causes. — Direct infection with secretion, or increase of the micro- organisms already present in the conjunctival sac, favoured by conditions which lower the resistance of the tissues, either locally by causing hyperaemia, or generally through the system (impure air, exposure to cold, etc.). Perhaps also the microbes are more widespread or more virulent at certain times, as in the spring or autumn. Some of the above-mentioned causes act, no doubt in combination, in the conjunctivitis which accompanies impetigo, scarlatina, measles, and smallpox. Diplohacillus {Momx and Axen- Koch-Weeks bacillus. Secretion jeld). From a case of subacute from acute conjunctivitis. A few angular conjunctivitis. deeply stained Xerosis h. are also present. Pneumococciis. From a case of Gonococcus. From a case of catarrhal conjunctivitis. ophthalmia neonatorum. Xerosis bacillus. Culture from Xerosis bacillus. Culture, diph- normal conjunctiva, showing iew theroid form, clubs. From preparations and drawings by L. W. CHAP. III.] THE CONJUNCTIVA. 53 The Koch-Weeks hacillus produces an acute contagious con- junctivitis, which chiefly attacks young people, and occurs most frequently in an epidemic form. It is more severe in adults than in children ; and is often attended by an erythematous condition of the upper lids, or even by slight oedema. Ecchymoses occur on the bulbar conjunctiva. The pre- auricular glands are sometimes enlarged. The Koch-Weeks bacillus may be easily overlooked, as it is a very fine bacillus and stains feebly. This form of conjunctivitis is not common in Ireland. The Pneumococcus is responsible for a mild form of catarrhal ophthalmia, occurring in children or adults, sometimes in small epidemics. A characteristic sign of this variety of conjunctivitis is (according to Morax) an oedema or rose-coloured hyper^emia con- fined to the margin of the upper lid. It also gives rise to minute ecchymosis of the bulbar conjunctiva. The secretion is at times fibrinous. This variety does not appear to be as common in the United Kingdom as elsewhere. It is of short duration (ten days or so), and can be readily cured. The conjunctivitis associated with impetigo sometimes assumes a mild catarrhal form. Both Strepto- and Staphylococci are found to be present. The former can no doubt set up conjunctivitis, but attempts to produce conjunctivitis in man with virulent cultures of staphylococcus aureus have proved ineffectual. In rare cases catarrhal conjunctivitis has been caused by the Diplococcus Intracellularis Meningitidis, not necessarily accompanied by meningitis. In influenza epidemics conjunctivitis sometimes occurs along with the other symptoms, or it may precede them. It is due to the Influenza Bacillus, which is shorter and stouter than the Weeks B. but is difficult to distinguish from the latter. It is much rarer in adults than in children. Cases of conjunctivitis have also been observed, which were undoubtedly caused by the hay bacillus {B. Suhtilis.) In all of them particles of earth had found their way into the eye. The Prognosis of catarrhal conjunctivitis is good, if there be no reason to suspect that the mild form is but the commencement of a more severe inflammation. The infiltrations, and even the ulcers which sometimes form at the margin of the cornea are not often 54 DISEASES OF THE EYE. [chap. hi. of serious import, and usually heal, according as the treatment restores the conjunctiva to health. Treatment. — It will be advisable here to make a few observations on the treatment of conjunctivitis in general. Patients should always, in the first place, be warned of the danger of infecting other persons. And in order also to avoid re-infecting themselves, droppers should be sterilised, or at least should not be brought into contact with the eye when being used. For bathing the eye sponges should be avoided, and small pieces of lint employed, which must be burnt immediately after use. Bandages should not be worn, nor should the patient be confined to the house, unless in severe or complicated cases. In catarrhal conjunctivitis cold or iced compresses, with the use of a 1 in 5000 solution of sublimate as a lotion, should be used frequently at the onset, and in mild cases will alone bring about a cure. But the habit, which some patients so readily acquire, of bathing the eyes frequently with cold water should not be permitted, for it is deleterious to the conjunctival affection. When in a day or two the irritation and swelling have somewhat subsided — or from the very commencement, if there be discharge — a solution of nitrate of silver, of from 5 to 10 grains to §j, should be applied by the surgeon to the palpebral conjunctiva with cotton wool twisted on the end of a small piece of stick, such as is used for matches, the lid being well everted. The excess may be neutralised with solution of common salt. The neutralisation with salt water checks pro- longed action of the nitrate of silver, and obviates conjunctival staining (called Argyrosis, from apyvpos, silver) when the treatment is a lengthened one. The application is to be repeated after twenty- four hours, by which time the slight loss of epithelium, the result of the superficial slough, will have been repaired. Immediately after such an application cold sponging or iced compresses are useful, and grateful to the patient. Gentle removal of the loose coagula also gives much relief. Of the organic silver salts the best are protargol, in 5 to 20 per cent sol., sophol 5 per cent., and argyrol 25 per cent. They do not coagulate albumen, and are therefore supposed to have greater penetrating power, and are practically painless. Personally we still rely on the nitrate in preference to them. Even weak solutions of nitrate of silver as eye-drops to be used CHAP. III.] THE CONJUNCTIVA. 55 at home by the patient, should be avoided, for staining of the con- junctiva is very apt to be caused in this way. Protargol and argyrol also cause staining. Subconjunctival injections of Potassium Iodide, 30 per cent, to saturated sol., help to remove argyrosis. Three or four minims only are injected at a time on account of the rather severe reaction. Should the surgeon be unable to see the patient daily, astringent and antiseptic eye-drops are very beneficial, and indeed often effect a cure. Sulphate of zinc (gr. ij to the 5J), with or without Tinct. Opii, 3jj alum (gr. iv to 5J), tannic acid (gr. v to viij to §j) are those which are most commonly used. They may be combined with boracic acid in saturated solution, corrosive sublimate (1 — 5000), or oxycyanate of mercury (1 — 2000). Acetate of lead (gr. 1 or ij to 5J) can also be prescribed, provided the cornea be intact; other- wise deposits of lead are liable to form in it. A weak boracic acid ointment should be applied along the margins of the lids at bedtime. It prevents the adhesion of the lids in the morning, which is not only unpleasant to the patient, but also prevents free drainage of the secretion during sleep. Diplobacillary or Angular Conjunctivitis.— This form of in- flammation requires a description apart, not only because it pre- sents a definite clinical picture, but also because it readily yields, to a particular line of treatment. It presents the appearance of a subacute or chronic conjunctivitis, the congestion being limited to the palpebral conjunctiva, more especially of the lower lid, and to the caruncle. The secretion is very scanty, and makes its appear- ance most commonly round the inner canthus, as a slight greyish- white collection, but still the lids are often stuck together in the mornings. The most characteristic sign, and one which has given rise to the name " Angular," is a peculiar moist hyperaemia, with superficial excoriation, of the skin at the margin of the lids, which usually surrounds the canthi, especially the inner canthus, although the whole margin of the lids may be affected by it. In very mild cases this condition of the skin may be absent. The subjective symptoms consist in sensations of heat, pricking, and itching, and are always much worse in the evening. Corneal affections are not common, but occasionally small superficial marginal ulcers occur ; and, less frequently still, severe central ulcers with hypopyon (see chap. v.). 56 DISEASES OF THE EYE. [chap. hi. The disease is chiefly met with in adults, but it also occurs in children, in whom it may even cause blepharitis. We have often seen it too as a complication of trachoma in the later stages. Cause. — The exciting cause is the Diplobacillus of Morax and Axenfeld, the largest of the micro-organisms found in the con- junctival sac (see p. 51). It grows only on sohd media containing serum, in which it produces very characteristic clear depressions. Inoculation easily succeeds in reproducing the disease, but only in human beings. The diplobacilli have also been found in the nose, but it has not been definitely ascertained whether or not they reach the latter through the nasal duct. Treatment. — This affection shows no tendency to spontaneous cure, and, if neglected, it may last for many months ; but fortunately we have in sulphate of zinc an unfailing remedy. Solutions of from 4 to 10 grains to the ounce will effect a cure in ten days or so, and are much more efficacious than very weak solutions, and are not very painful. Cocaine may be added for patients of nervous tem- perament. In order to prevent a relapse, the treatment should always be continued for about a week after the subjective symptoms have disappeared. If the lids be tender, an ointment of oxide of zinc (10 per cent.) and icthyol (2 to 5 per cent.) is very useful. The sulphate of zinc does not kill, but merely checks the growth of the bacilli, hence the necessity for prolonging the treatment after an apparent cure. In rare cases of idiosyncrasy to zinc sulphate, resorcin in 2 or 3 per cent, aqueous solution gives good results. Chronic Simple or Chronic Catarrhal Conjunctivitis.— This form of conjunctivitis occurs in adults and old people, and is extremely obstinate, often lasting for years, and sometimes, with or without intermissions, even for a lifetime. The objective signs vary in degree from those of simple hypersemia without apparent secretion to a moderate catarrh with muco-purulent discharge. But they are never so pronounced as in the acute form of the disease, and the bulbar conjunctiva is seldom much injected. The subjective symptoms resemble those which have been men- tioned in the descriptions of hypersemia and acute catarrh. They are always worse in the evening, and patients often complain that when they attempt to read, the upper lids feel heavy and inclined to close, so that they feel sleepy. A sensation of dryness of the eye- CHAP. III.] THE CONJUNCTIVA. 57 ball is also experienced, when the secretion is scanty or absent. In many cases, however, the sensations complained of are much in excess of the objective appearances. In the later stages, the conjunctiva, in muco-purulent cases, becomes rough or velvety, from hypertrophy of the papillae, and ectropion of the lower lid, epiphora, and blepharitis may result. The skin of the lower lid, from the constant irritation caused by the discharge, becomes eczematous and stif?, the inner end of the lid then becomes everted, so that the punctum lacrimale no longer lies in normal contact with the eyeball, and this, together with narrowing of the punctum and canaliculus by the hypertrophied conjunctiva, leads to epiphora, which again intensifies the irritation of the skin, and still further increases the ectropion. Marginal ulcers of the cornea, too, are liable to occur in old people with chronic conjunctival catarrh. The Causes of this affection are very numerous. It seldom originates in an acute catarrh, but more commonly begins gradually, and owes its origin to local irritation of the conjunctiva or to con- stitutional causes. Amongst the former are included dust, chemicals, smoke, bad ventilation, exposure to heat or steam, in- turned eye- lashes, infection from the lacrimal sac, errors of refraction, prolonged reading by artificial light, sleeplessness, and constant exposure to wind or rain. Less well-known causes are : inefficient closure of the eyelids at night, so that a portion of the eyeball remains exposed to the atmosphere ; purulent infection of the ducts of the Meibomian glands, or soHd infarcts in the Meibomian glands or in small con- junctival cysts. In many cases no definite cause can be assigned. Treatment is often unsatisfactory, partly owing in many cases to the impossibility of removing the cause when this is due to the nature of the patient's occupation. Indications for treatment are provided by a consideration of the above-mentioned causes. Atten- tion should also be paid to the general health ; relief of constipa- tion ; avoidance of alcoholic stimulants ; correction of errors of refraction and presbyopia ; treatment of the lacrimal apparatus (chap, xix.) and of ectropion (chap, xviii.). In case of defec- tive closure of the lids, a bandage at night may be applied. Sup- puration in the Meibomian ducts can be effectually relieved by expression of their contents, daily if necessary. Any solid white infarcts^ if they project above the surface, should be picked out of 58 DISEASES OF THE EYE. [chap. hi. the palpebral conjunctiva with the point of a needle or knife. With regard to local applications, astringents are the most useful, but they should not be too irritating. Nitrate of silver may be necessary if there be discharge or hypertrophy of the conjunctiva. Protargol, argyrol, or other organic silver salts are less painful, but the possibility of causing argyrosis should not be forgotten. Other useful astrin- gents are alum in solid stick, or in J to 1 per cent, solution ; copper sulphate ; lead subacetate ; tannic acid in solutions containing 1 or 2 grains to 5J. Boracic acid too may be used in saturated solution, but it is the mildest and least active of all. Adrenaline gives only temporary relief. Frequent use of cocaine is not to be recommended, as it renders the cornea vulnerable to micro-organisms by deranging its epithelium. Very mild cases of diplobacillary conjunctivitis may not be accompanied by the characteristic ex- coriation of the skin, and may then resemble a simple chronic conjunctivitis ; but here a bacteriological examination would at once establish the diagnosis and suggest the appropriate treatment. Acute Blennorrhoea of the Conjunctiva, or Purulent Ophth- almia. — This very dangerous affection, which statistics show to be one of the commonest causes of blindness, is usually seen either as gonorrhoeal ophthalmia or as blennorrhoea neonatorum. Etiology. — In gonorrhoeal ophthalmia the etiological moment is the introduction of some of the specific discharge from the ure- thra or vagina into the conjunctival sac ; while in blennorrhoea neonatorum the infection is believed to take place, either during or just after the passage of the head through the vagina, by ab- normal secretion from the latter finding its way into the infant's eyes. A few instances have been observed of infants born with the disease. Prolonged labour, due to early rupture of the mem- branes, or faulty head presentations, and also repeated examina- tions, would assist infection before delivery. Inoculation may also occur a few days after birth by pus conveyed by the fingers of the mother or nurse, or by towels, etc., used for washing the child's face. The more severe cases of blennorrhoea neonatorum are caused by a vaginal discharge, which is almost always gonorrhoeal, and Neisser's gonococcus, which is the exciting agent, can be found in the discharge from the vagina and in the secretion from the eye. It may be found in the epithelial cells, or in the pus cells, or free. Mild catarrhal conjunctivitis also occurs in newborn infants, and in CHAP. III.] THE CONJUNCTIVA. 59 these cases the ordinary microbes associated with that condition are present, and occasionally the bacterium coli ; but in rare cases even the gonococcus may produce a mild reaction, probably owing to attenuation of the virus by dilution or drying. It should also be noted that a typically purulent ophthalmia has, in exceptional cases, been observed in infants (Morax) without the presence of any micro-organisms, but then it usually takes a benign course. If the infection take place during or immediately after birth, the disease appears most commonly on the third day, but it may appear at any time from the second to the sixth day, according to the virulence of the secretion. If the inflammation come on later than the sixth day, it may be concluded that the infection was produced secondarily by the vaginal discharge being introduced into the eye by the fingers of the mother or nurse, etc. While purulent ophthalmia in adults is usually gonorrhoeal and due to the gonococcus, it may exceptionally be the result of in- fection by the Koch-Weeks bacillus ; the cases due to this bacillus, however, are not so serious as those caused by the gonococcus. In newborn infants both eyes are commonly affected. The reverse is the case in adults, in whom also the disease is more severe. Symptoms and Progress. — In mild cases the bulbar conjunctiva may be but little, or not at all, affected, the palpebral conjunctiva alone becoming velvety and discharging a small amount of pus, while there may be no swelling or oedema of the eyelids. In severe cases of blennorrhoea of the conjunctiva there is, soon after the onset, serous infiltration of the palpebral mucous membrane — which consequently becomes tense and shiny — marked chemosis of the bulbar conjunctiva, serous discharge, dusky red- ness, and swelling of the eyelids — which makes it difficult to evert them — pain in the eyelids, often of a shooting kind, burning sensa- tions in the eye, and photophobia. This first stage, or period of infiltration, lasts from forty-eight hours to four or five days. The preauricular lymphatic glands may be swollen and tender, and a rise of temperature may occur. Then begins the second or furulent stage, in which, owing to swelling of the papillae, the palpebral conjunctiva becomes less shiny and more velvety ; while the discharge alters from serous to the characteristic purulent form, the chemosis, however, remaining unaltered, or becoming more firm and fleshy. The swelling of the 60 DISEASES OF THE EYE. [chap. hi. lids continues, the upper lid often becoming pendulous and hang- ing down over the under lid ; while, at the same time, it becomes less tense and more easily everted. Gradually the chemosis and swelling of the conjunctiva and eyelids subside, and the discharge lessens, the mucous membrane finally being left in a normal state, unless in a small percentage of cases in which chronic blennorrhoea remains. A moderately severe attack of conjunctival blennorrhoea lasts from four to six weeks. A delicate scarring of the conjunctiva in the fornices may be sometimes left after the attack. Complications with corneal affections form the greatest source of danger in this affection. They are found chiefly in four different forms. (1) Small epithelial losses of substance which are apt to go on to form deep perforating purulent ulcers. (2) The whole cornea becomes opaque (diffusely infiltrated), and greyish purulent in- filtrations may form towards its centre. (3) An infiltration may form at the margin of the cornea, and give rise to a marginal ring ulcer, and, later on, to sloughing of the whole cornea. (4) A clean-cut ulcer may also form at the margin of the cornea. These ulcers are par- ticularly apt to occur where there is much chemosis, which overlaps the margin of the cornea ; and, being hidden in this way, they are easily overlooked. The chemosis should be pushed aside with a probe, and these peculiar ulcers looked for. They are very liable to perforate. All the foregoing forms of corneal complication occur both in adults and infants, and the earlier they occur the more likely are they to result in perforation and permanent opacities. It is believed by some that corneal complications are due to secondary infection with other micro-organisms. The severer the case, especially the more the bulbar conjunctiva is involved in the process, the more likely is it that corneal com- plications will arise. Severe chemosis is less common in the blennor- rhoea of the newborn than in gonorrhoeal ophthalmia, and this may be the reason for the fact that the latter is much the more dangerous affection of the two. The Prophylaxis of purulent ophthalmia is a matter of the first importance. It should form part of the routine of lying-in practice. Careful disinfection of the vagina before and during birth, and the most minute care in cleansing the face and eyes of the infant immediately after birth with a non-irritating disinfectant {e.g. a CHAP. ITT.] THE CONJUNCTIVA. 01 solution of corrosive sublimate 1 iu 5000), are to be recommended. Crede's method is as follows : — When the child is in the bath, the eyes are carefully washed with water from a separate vessel, the lids being scrupulously freed, by means of absorbent wool, of all blood, slime, or smeary substance ; and then, before the child is dressed, a few drops of a 2 per cent, solution of nitrate of silver are instilled into the eye.^ The conjunctival irritation which some- times follows is unimportant as compared with the immense advantages which result from this procedure. By its aid Crede reduced the percentage of his cases of ophthalmia neonatorum from 8 or 9 per cent, to 0*5 per cent. Very good results have also been obtained with 5 per cent, sophol. In all cases of gonorrhoea it is the duty of the surgeon to explain to his patients the danger of carrying any of the urethral discharge to their eyes ; and to charge them to exercise punctilious cleanli- ness as regards their hands and finger-nails, and care in the use of towels, handkerchiefs, etc. In respect of Local Treatment when the disease has become established : — In the very commencement of the affection the only local applications admissible are antiseptic lotions (Permanganate of Potash Solution, 1 in 10,000 ; Sublimate, 1 in 5000) and iced compresses, or Leiter's tubes. With the former the conjunctival sac should be freely washed out or irrigated. Syringing is dangerous both for patient and for operator, for in syringing out the conjunc- tival sac the corneal epithelium may be injured and the cornea may become infected ; and, as regards the operator, he is in danger of discharge spurting into his eyes. The iced compresses, or Leiter's tubes, should be kept to the eye for an hour at a time, with a pause of an hour, and so on, or even continuously. Cold inhibits the growth of the gonococcus. In this and in the next stage the chemosis, if severe, should be freely, and daily, incised with scissors. If the swelling of the lids be great, the external canthus should be divided wdth a scalpel from without, leaving the conjunctiva un- injured, in order to reduce the tension of the eyelids on the globe, and, by bleeding from the small vessels, to deplete the conjunctiva. Depletion alone can be obtained by leeching at the external canthus, and in many cases is of great benefit at the very commencement. ^ The general opinion now is that a 1 per cent, solution is just as efficient and less irritating. 62 DISEASES OF THE EYE. [chap. hi. If in iidults the cliemosis, palpebral swelling, and rapidity of the onset indicate that the inflammation is severe, it is well to place the patient quickly under the influence of mercury by means of inunctions or small doses of calomel, as by so doing the cliemosis is often rapidly brought down, and one source of danger to the cornea is removed. In the second stage {i.e. when the conjunctiva has become velvety and the discharge purulent) caustic applications are the most trust- worthy, and in this respect iodoform and other lauded means cannot compete with them. The surgeon should apply a solution of nitrate of silver of 10 to 20 grains in §j of water, to the conjunctiva of the everted lids ; or the solid mitigated nitrate of silver (one part nitrate of silver, two parts nitrate of potash) may be used, the first application being lightly made in order to test its effect, while careful neutralisation with salt water and subsequent washing with fresh water are most important. Iced compresses may be used to relieve the subsequent pain. An interval of twenty-four hours should elapse before the application is renewed. No remedy is of greater value in purulent ophthalmia than the above mentioned mitigated lapis, wdien the proper indications for its use are present, and when it is applied with care and intelligence. Betw^een the caustic applications, the pus should be frequently washed away from the eyelids, and from between the eyelids, with a -i per cent, solution of boric acid, or, better still, the conjunctiva should be douched with a solution of permanganate of potash (1 in 5000) or with a solution of corrosive sublimate of the same strength, and boric acid ointment should be smeared along the palpebral margins, to prevent them from adhering, and thus retaining the pus. No corneal complication contra-indicates the active treatment of the conjunctiva by the method just described. Iodoform, finely pulverised, has been much praised as a local application in the second stage of acute blennorrhoea of the conjunctiva. It is to be dusted freely on the conjunctiva once or twice a day. For our part we should trust to it alone in mild cases only. It can, however, be employed with advantage in combination with the above treat- ment. AVhen but one eye is aflected, it is generally considered neces- sary to protect its fellow from infection by means of a hermetic dressing. This may be made by applying to the sound eye a piece CHAP. III.] THE CONJUNCTIVA. 03 of lint covered with boracic acicT ointment, and over this a pad of borated cotton-wool. Across this, from forehead to cheek and from nose to temporal region, are laid strips of lint soaked in collodion in layers over each other ; or a piece of tissue guttapercha may take the place of the lint and collodion, its margins being fastened to the skin by collodion. The shields invented by Maurel and by BuUer are serviceable for this purpose. Yet with careful instructions given to the patient, and average intelligence on his part, protection of the sound eye is not necessary. In private cases we do not close the second eye, and have never had ill effects in consequence. Any sign of congestion was met by the application of a 2 per cent, solution of nitrate of silver, and it always proved sufficient to check the development of the disease, as it does in Crede's method of prophylaxis. Patients should be advised to sleep on the side of the affected eye, in order to prevent the discharge from trickling on to the other side of the face. Treatment of Corneal Complications. — The involvement of the cornea does not contra- indicate the use of the methods already described, but rather demands their vigorous application. In addition, atropine will relieve pain and diminish the tendency to iritis. Eserine is sometimes employed with the object of reducing the tension, and so improving the nutrition of the cornea by facili- tating the lymph circulation, and also on account of its antiseptic properties. But, as its action on the normal tension is practically nil, and its antiseptic properties are very slight, it is better to reserve it for cases of marginal ulcer with prolapse, or danger of prolapse, of the iris, since by the contraction of the sphincter the iris is drawn away from the periphery. Greater care is now required in everting the lids, lest pressure on the globe should cause rupture of the ulcer ; and it must be remembered that when a case of acute blennorrhoea first presents itself, the surgeon, not knowing the condition of the cornea, must use the utmost caution in making his examination, and yet must never fail to get a view of the cornea for the purposes both of prognosis and of treatment. At each visit the cornea must be examined, and it may be found that, as the conjunctival process subsides, any existing corneal affection also improves. But even though the conjunctiva be improving, the corneal process may progress, until, finally, the ulcer perforates. CA DISEASES OF THE EYE. [cHAr. in. Should a corneal ulcer become deep, aud seem to threaten to perforate, paracentesis of the floor of the ulcer must be resorted to without delay. Through the small linear opening thus made no prolapse of the iris, or else a relatively small one, takes place. The reduction of the intra-ocular tension after the paracentesis promotes healing of the ulcer. It is often desirable to evacuate the aqueous humour, by opening the little incision in the floor of the ulcer with a blunt probe, on each of the two days after the operation. If an ulcer perforate spontaneously, the aqueous humour is evacuated, and, unless the ulcer be opposite the pupil and at the same time small in size, the iris must come to be applied to the loss of substance. Should the latter be very small, the iris will simply be stretched over it and pass but little into its lumen, and when healing takes place will be caught in the cicatrix, which is but slightly, or not at all, raised over the surface of the cornea, and the resulting condition is called Anterior Synechia. If the perforation be larger, a true prolapse of a portion of the iris into the lumen of the ulcer takes place. This prolapse may either act as a plug, filling up the loss of substance and keeping back the contents of the globe, but not protruding over the level of the cornea, or it may bulge out over the corneal surface as a black globular swelling, and may then play the part of a distensor of the opening, causing fresh infiltration of its margins. In either case cicatrisation will eventually occur ; and if the scar be fairly flat, it is called an Adherent Leucoma, but if it be bulged out, the term Partial Staphyloma of the Cornea is used. If the perforation be very large, involving the greater part of the cornea, with prolapse of the whole iris and closure of the pupil by exudation, the result is a Total Staphyloma of the Cornea. The lens may lie in this staphyloma, or it may retain its normal position, but become shrunken. The question of the treatment of a recent prolapse of the iris in cases of blennorrhoeic conjunctivitis is an important one. It has been, and is still largely, the practice to abscise small iris-pro- trusions down to the level of the cornea, or if large to cut a small bit off their summits, with the object of obtaining flat cicatrices. But in cases of blennorrhoea this proceeding opens a way for purulent infection of the deep parts of the eye, and serious consequences may result. It is better to confine interference with the iris in CHAP. III."! THE CONJUNCTIVA, these eyes to incision of the prolapse, when it seems to be acting as a distensor of the opening, causing fresh infiltration of the cornea ; or merely to instil eserine, which has a marked effect in diminishing the size of the protrusion. The margins of the eyelids may be gummed together by sero- purulent secretion, while the eyelids are bulged out by the pent-up fluid behind them ; the attempt to open the eye should then be very cautiously made, lest some of the retained pus spurt into the surgeon's eye. The surgeon should also be most careful to wash thoroughly and disinfect his hands and nails at the conclusion of his visit. In cases of blennorrhoea neonatorum, when the ulcer has been small, on perforation taking place, the lens, or rather the anterior capsule, comes to be applied to the posterior aspect of the cornea. The pupillary area is soon filled with fibrinous secretion. The open* ing in the cornea ultimately becoming closed, the iris and lens are pushed back into their places by the aqueous humour which has again collected. Adherent to the anterior capsule where it Jay against the cornea is a deposit -of fibrine, which gradually becomes absorbed by the aqueous humour. In the meantimxe changes have been produced by this exudation on the corresponding intracapsular cells, which result in a small, permanent, central opacity at that place, where there is also a sHght elevation of pyramidal shape over the level of the capsular surface. This condition is called central capsular cataract, or pyramidal cataract, and rarely results from cornea] perforation in adults. In cases of blennorrhoea neonatorum an inflammatory swelling of the joints, so-called gonorrhoeal arthritis, is very occasionally seen. The gonococcus has been found in the fluid removed from the joints in some cases, while in others only the usual pyogenic cocci were present. Even more rarely do peri- and endo-carditis, pleuritis, and meningitis occur. Metastatic Gonorrhoeal Ophthalmia is sometimes met with in adolescents or adults, as an accompaniment of gonorrhceal artliritis. It is apt to occur with cessation of the urethral discharge. Both eyes are nearly always affected. The disease presents the appearance of a moderate catarrhal ophthalmia chiefly affecting the bulbar conjunctiva, with scanty secretion, but it is occasionally complicated with keratitis, iritis, or scleritis. It shows a great tendency to recur with a relapse of the " rheumatism." On the other hand, the conjunctival affection may be the only sign of a 5 OG DISEASES OF THE EYE. [chap. hi. systemic affection. Gonococci have sometimes been found in the secre- tion from the conjunctiva. Tliree views are held with regard to causa- tion : (a) that the gonococci are carried to the eye through the circulation ; (6) that it is due to a gonotoxin ; or (c) that the gonococci prepare the soil for a mixed infection. It is easily cured by local treatment. Quite recently good results have been obtained, in all forms of gonor- rhoeal infection, with an atoxic gonococcal vaccine prepared in the Pasteur Institute of Tunis according to a formula of Nicolle and Blaizot. * Membranous Conjunctivitis. — This disease is characterised by the existence of a fibrinous exudation, either on the surface or in the substance of the conjunctiva, in addition to the other symp- toms of inflammation. It was formerly believed, on purely clinical grounds, that the mild form of the disease, known as croupous conjunctivitis, was totally different in nature from the severe or diphtheritic form, and later on this view seemed to be borne out by the discovery of the Klebs-Loeffler bacillus in the diphtheritic cases ; but further experience of the bacteriology of membranous conjunctivitis has altered this view. Not only is the diphtheria bacillus found in mild croupous cases, but any of the micro-organisms which commonly cause conjunctivitis, may give rise to fibrinous exudations and the formation of membranes. The same condition in varying degrees of severity can be produced by chemical irritants, such as lime, ammonia, etc., and also by jequirity. Lastly, the diphtheria bacillus may, in rare cases, lead to a simple catarrhal inflammation without the production of a false membrane. The presence of a membrane therefore is only a symptom, and is not necessarily pathognomonic, although it is very suggestive of the Klebs-Loeffler bacillus as the cause. In severe cases strepto- and staphylo-cocci are generally associ- ated with the diphtheria bacillus, and indeed the streptococcus, staphylococcus, and pneumococcus acting alone can occasionally cause severe membranous inflammation of the conjunctiva. There is reason to believe that the diphtheria bacillus can only act on the conjunctiva when the epithelium has been injured, say by a slight, even imperceptible trauma, or by a previous inflammation. The Xerosis bacillus must not be mistaken for the Klebs-Loeffler bacillus ; the only reliable method of distinguishing one from the other is by inoculation in animals. Microscopically the false membrane consists of a fibrinous net- CHAP. III.] THE CONJUNCTIVA. 67 work contaiiiiiig leucocytes, a few epithelial cells, and often micro- organisms. In the so-called croupous cases the underlying epithelium may or may not be adherent to the false membrane, but even in the latter event, although the epithelium separates along with the membrane, the surface left is smooth and becomes covered by regenerated epithelium, so that no trace of scarring occurs. On the other hand, in the severe or diphtheritic cases the sub- mucous tissue is involved in the exudation, the vessels become compressed by it, and this leads to necrosis. When the dead tissue has been cast off a granulating surface is exposed which heals by cicatrisation. These are true granulations in the surgical sense, and are therefore quite different from the " granulations " of trachoma. Etiology. — Membranous conjunctivitis in all degrees of severity is met with for the most part in children, more especially in those under four years of age. The Streptococcal form often follows an attack of measles or scarlatina, and is frequently accom- panied by eczema or by ulcers of the skin in the neighbourhood of the eyes. One or both eyes may be attacked. It is an acute disease, which occurs sporadically or in epidemics, but a few chronic cases have been seen to last for many months. Clinically, the mild or croupous form of the disease can readily be distinguished from the severe or diphtheritic ; hence they will be described separately, with the understanding that the real nature of each case can only be decided by careful bacteriological examination. Croupous Conjunctivitis. — The symptoms are those of catarrhal conjunctivitis, to which in a few days is added the appearance of a greyish pellicle on the palpebral conjunctiva, sometimes also on the retro-tarsal folds, but rarely on the bulbar conjunctiva. The false membrane can be peeled off, leaving a mucous surface underneath which may or may not bleed. The lids, which may be red and swollen, are always soft and easily everted. After a week or so the second or secreting stage sets in, with the appearance of a discharge, and the false membrane becomes separated, leaving a healthy mucous surface which gradually returns to its normal condition, without any trace of scarring. Observations with reference to corneal complications vary, some observers never having seen them, 68 DISEASES OF THE EYE. [chap. hi. while others have noted them in 40 per cent, of their cases. Con- stitutional symptoms are much less frequent than in the severe or diphtheritic variety of this affection. Treatment. — In the first stage iced compresses or Leiter's tubes applied to the lids, with antiseptic cleansing of the conjunctival sac. No caustic should be used in this stage, as it is apt to produce corneal changes. Sulphate of quinine insufflated, or in 2 per cent, solution, is praised by some surgeons as a useful application at this period. In the secreting stage nitrate of silver applications should be made in the usual way. When the Klebs-Loeffler bacillus is the active agent antitoxin should be used. Simple instillations into the conjunctival sac, with which we have obtained a good result, may suffice in these mild cases. (See Treatment of Diphtheritic Conjunctivitis.) Diphtheritic Conjunctivitis. — There is no more serious ocular disease than this, for it may destroy the eye in twenty-four hours ; while in severe cases treatment is almost powerless. Fortunately it is exceedingly rare in these countries. The subjective symptoms of its initial stage are similar to those of blennorrhoeic conjunctivitis, but severer, especially in the matter of pain. The objective symptoms differ from those of blen- norrhcea, in that the lids are excessively stiff, owing to plastic in- filtration of the sub-epithelial and deeper layers of the conjunctiva, while the surface of the mucous membrane is smooth, and of a grey- ish or pale buff colour. If an attempt be made to peel off some of the superficial exudation the surface underneath will be found of the same grey colour, not red and vascular, as in croupous con- junctivitis. Ulcers of the skin covered with a greyish membrane are often present on the eyelids and cheek, or round the nostrils or lips, and the preauricular glands are enlarged. This stage of infiltration lasts from six to ten days, and constitutes the period of greatest peril to the eye ; for while it lasts the nutrition of the cornea must suffer, and sloughing of that organ is extremely apt to take place. Towards the close of the first stage the fibrinous infiltration is eliminated from the eyelids, and the conjunctiva gradually assumes a red and succulent appearance, and at the same time a purulent discharge is established. This constitutes the second or Uennorrhceic stage. A third stage is formed by cica- tricial alterations in the mucous membrane, which often lead to CHAP. TIL] THE CONJUNCTIVA. 69 symblepharon, or to xerophthalmos ; so that, even if the eye escape corneal danoers in the first and second stages, others almost as serious may await it in the final stage. Corneal complications are most likely to occur in the first stage, and are then also most likely to prove destructive to the eye. The earlier they appear the more dangerous are they. If the blennor- rhoeic stage come on before corneal complications appear, or even before an ulcer contracted in the first stage has advanced far, thev are more easily controlled. In the third stage corneal affections, if they occur, are of a chronic nature and are generally accompanied by vascularisation. This disease is nearly always combined with constitutional symptoms, such as fever, malnutrition, albuminuria, and is some- times fatal ; but, strange to say, it is very rarely followed by para- lysis, even of accommodation. It has seldom been observed to follow diphtheria of the throat, although the opposite sequence is not uncommon. Treatment. — If the disease be due to the Klebs-Loeffler bacillus, antitoxin serum is the sovereign remedy, and as the identifica- tion of the diphtheria bacillus takes time, any presumption of its presence should be acted upon without delay. The injections may be given under the skin of the eyelids, and instillations into the conjunctival sac may be made as well. In streptococcal cases anti-streptococcus serum may be used, but it does not act so well as the diphtheria antitoxin. Precautions should of course be taken to avoid the transference of the disease to other persons. In cases caused by the pneumococcus, Romer's pneumococcus serum may be used. These remarks also apply to croupous con- junctivitis. Local treatment in the first stage should consist in cold applica- tions and antiseptics ; later on, warm fomentations, especially if the patient finds them more agreeable, can with advantage be substituted for the cold. In the secreting stage the same lines of treatment should be followed as in catarrhal conjunctivitis, except that greater precaution should be taken in using nitrate of silver ; the greater the discharge the more freely it may be applied. Corneal ulcers must be dealt with, whenever they arise, in the same way as though the case were one of blennorrhoeic conjunctivitis. When the purulent discharge ceases, solutions containing soda or glycerine 70 DISEASES OF THE EYE. [chap. hi. may be prescribed as lotions for the conjunctiva, to relieve the xerophthalmos. Hay Fever. — This is not uncommon among the better classes in these countries, although it is rarely seen in our hospital patients. The symptoms, in those liable to it, appear in the early summer each year, and disappear again in the course of six weeks or two months. They consist in catarrh of the nostrils, accompanied by great itching of them and frequent sneezing ; while the conjunctiva, especially in the lower fornix, becomes somewhat hypersemic, and there is lacrimation. There is excessive itching of the eyes, which renders the patient most wretched, and compels him to rub his eyes violently. There is photophobia. The respiratory tract may become involved, with some bronchitis and asthma, and general malaise and elevation of temperature are present. Some- times the eyes alone are affected. There is no tendency to corneal com- plications. Dviring an attack the eosinophile cells in the conjunctival sac are increased in number as in Spring Catarrh. Treatment is of no avail in preventing the annual recurrence of the affection, nor is it of much use in alleviating the attack. No strong local application should be employed. Weak collyria, or ointments, of sulphate of zinc, or copper, boric acid, or sublimate, etc., may be tried. Adrenaline, cocaine, or holocaine eye drops (2 per cent.) afford the best relief. Dark glasses should be worn. Dunbar's hay fever serum, called pollantine, has been used with benefit in some cases. Trachoma (rpaxts, rough), Granular Conjunctivitis, or Granu- lar Ophthalmia (also called Egyptian Ophthalmia and Military Ophthalmia). — In this disease, in addition to the usual appearances of simple conjunctivitis, there are developed translucent greyish or pinkish-grey bodies about the size of the head of a pin or larger, situated in, and close to the fornix conjunctivae, chiefly of the upper lid. They also occur on the tarsus, in the lower fornix, and some- times on the plica semilunaris, but are very rarely met with on the bulbar conjunctiva. The tarsal growths are smaller, flatter, and yellower in colour than those seen in the fornix. These bodies are the trachoma bodies or granulations, or " sago grains," they somewhat resemble the follicles of follicular conjunctivitis, except that they are paler, more irregular in size and less apt to occur in rows. Microscopically they exhibit the structure of hjmplioid follicles, and consist of an outer zone of small lymphocytes and a central mass of larger endothelioid cells, amongst which some very large cells are found with irregular processes and cell-inclusions. These CHAP. III.] THE CONJUNCTIVA. 71 are the so-called " trachoma cells " or " corpuscle cells " ; they are supposed to be phagocytes or enlarged connective tissue cells, and have even erroneously been taken for protozoa, but since they exist in normal lymph follicles in other places, they are not in any sense specific. The cellular elements of the follicle lie in the meshes of a delicate reticulum, the follicle itself being surrounded by a vascular network and a more or less defined capsule. The unevenness of the conjunctival surface is still further in- creased by a luxuriant formation of fapillce due to the folding of the inflamed and hypertrophied mucous membrane, which also leads to the development of microscopic glands and later on of small cysts. The latter are met with in the furrows between the papillae, or they may be produced by solid downgrowths of epithe- lium, which become softened in the centre. The follicles ultimately become absorbed, or soften, and extrude their contents on the surface. In any case their disappearance is followed by the development of fibrous cicatricial tissue, from the shrinking of which various complications, which will be mentioned later on, ensue. The tarsus may be involved in the inflammation, and in many cases a vascular, richly cellular layer called pannus forms in the cornea between the epithelium and Bowman's membrane. Etiology and Cause. — There can be no doubt but that this disease is contagious, and that it is the result of a specific cause, the nature of which is still unknown. Peculiar cell-inclusions have been found in the epithelial cells, in smear pre- parations of the secretion or of the scrapings taken from recent untreated ^ cases. The appearance which they present varies in different stages. t,. oo /f • • 1 J • Fig. 38.— Epithelial cell bis. 38 (from an ormmal drawmg, , ^, • -• t ^ ^^ ^ , , from the conjunctiva ot a case for which we are indebted to the of trachoma. kindness of Professor Greeff , one of («) ceii inclusions, forming a duster the discoverers of these Cell-inclu- in the protoplasm of the cell, dose to the nudeus (6), (r) isolated granules. sions) illustrates one of the most characteristic stages. The nature of these fine granules has not, however, been ascertained, and their causative relation to granu- lar ophthalmia has not been established. Unfortunately it has not yet been possible to isolate or cultivate them, and hence no 72 DISEASES OF THE EYE. [chap. hi. pure cultures have been obtained with which to perform experi- ments. More recently, similar cell inclusions have been found in non-gonococcal forms of ophthalmia neonatorum (and even in the normal conjunctiva), and for this and other reasons the theory has been advanced that these minute bodies are an involution form of the gonococcus. They have also been found in cases of gonorrhoea, both in males and females, but it is still uncertain whether any real relation exists between this disease and granular ophthalmia. By some these cell-inclusions are held to be merely products of nuclear degeneration. The histological changes are not peculiar to this disease alone — the papillary hypertrophy is well seen in chronic blennorrhoea, for instance — and even lymph follicles occur from other causes ; for 'example, from atropine irritation and in tuberculosis. In- fection occurs only by transference of the secretion from one eye to the other by means of fingers, towels, handkerchiefs, etc. Hence slovenly personal habits, overcrowding of dwellings, schools, or barracks help the disease to spread from one individual to another when it once gains a foothold in a country. A great deal, however, remains to be learned as to the manner in which contagion takes place. The infectiousness of chronic cases cannot be very great, for nurses and doctors rarely, if ever, become infected by their patients. Neither do we see trachoma patients infecting surgeons, nurses, or other patients in the hospitals in Ireland, where the disease is so prevalent. Were the infectiousness of the disease very great, even the precautions taken in a well-ordered hospital against contagion would hardly be sufficient to prevent such an occurrence occasionally. Moreover, inoculation experiments do not always succeed. Amongst the better classes, both here and elsewhere, the disease is very uncommon. Even the poor in high, dry, mountainous countries are almost free from it, so that, probably, the atmospheric conditions play some part in the etiology. Some hold that the affection is dependent on constitutional disease, such as scrofula, tuberculosis, syphilis, etc. ; but we cannot endorse this view. No doubt many of these patients are anaemic and out of health, but this is due to the moping habits they contract, and the little open-air exercise they take in consequence of their semi-blindness. The effect of race as a predisposing cause is doubtful. Jews CHAP. III.] ^ THE CONJUNCTIVA. 73 are said to be peculiarly liable to the disease, but it must be re- marked that in them as in others it only occurs amongst the very poor. Trachoma generally attacks both eyes and is an extremely chronic affection. An acute form is described, which, however, must be very rare, as it is practically non-existent in Ireland, although the chronic variety of the disease is so common here. Acute Trachoma, or Acute Granular Ophthalmia. — The symptoms are those of a more or less acute purulent ophthalmia, associated with the characteristic appearances of trachoma. The acute symp- toms are really due to an additional infection by the gonococcus or Koch- Weeks bacillus. Treatment. — In the early stage the treatment is the same as for acute blennorrhoea, while at a later period the same methods are adopted as in chronic trachoma. Chronic Trachoma, or Chronic Granular Ophthalmia. — In the early stage, which may pass unnoticed, this disease is often un- accompanied by inflammation, and is then unattended by any dis- tressing symptoms, except that the eye may be more easily irritated by exposure, or more readily wearied by reading or near work. At this period the conjunctiva will be found free from injection except perhaps at the inner and outer corners of the palpebral portion of the upper lid, where there may be a slight roughness or some small follicles. But later on greyish-white semi-transparent trachoma bodies, of the size of a rape-seed and less, may be found in the upper fornix, sometimes only by careful examination, or again, they may be seen disseminated over the conjunctival surface of the upper lid, and protruding from it. Gradually these trachoma bodies or granu- lations give rise to a more or less active vascular reaction, attended with swelling of the papillae and purulent discharge — in short, slight blennorrhoea. This is the stage of progression (Fig. 39). The patients then begin to be more inconvenienced, owing to the discharge which obscures their vision, to sensations of weight in the lids and of foreign bodies in the eye, and to partial ptosis, which gives them a sleepy look. This is generally the earliest stage at which we see the disease. The enlarged papillae often grow to a great size, completely hiding the granulations, constituting what is known as the " papillary form " of the disease. In this stage the granulations may become absorbed, and the disease undergo cure ; but more commonly it 74 DISEASES OF THE EYE. [chap. hi. makes further progress. Fresh granulations appear, while the old ones increase in size and undergo a peculiar gelatinous change. They then often become confluent, leaving only here and there an island of vascular mucous membrane. Sometimes the trachoma bodies are very small, and present the appearances of minute yellowish dots, and in this form they are not always easily found. Gradually the follicles become absorbed, or more rarely their contents are expelled, and the connective tissue proliferates so as to cause more or less extensive scarring of the conjunctiva. This constitutes the cicatricial stage of the disease. The scarring frequently / /. .A Fig. 39. — Granular ophthalmia ; Fig. 40. — Granular ophthalmia ; progressive stage. cicatricial stage, with pannus and trichiasis. presents a reticulated appearance, and in many cases assumes the form of a white line situated in the subtarsal sulcus. Fig. 40. The tarsus may undergo fatty or hyaline degeneration or be- come hypertrophied, while the diseased conjunctiva on the inner surface of the lid causes curving of the tarsus with entropion and distortion of the bulbs of the eyelashes, followed by irregular grou'th of the latter, with resulting trichiasis and distichiasis. These changes are represented in Fig. 41. The bulbar conjunctiva may become atrophied, cease to secrete, and become dried, giving rise to xerosis. In consequence also of the shrinking of the conjunctiva, the fornices may become partially or wholly obliterated, thus causing symblepharon (adhesion of the eyelids to the eyeball). The great danger of granular ophthalmia lies in the complications which may attend it, or which follow in its wake ; the former are pannus, ulcers of the cornea, and severe purulent conjunctivitis, while the latter are the distortions of the lids and eyelashes just referred to. CHAP, III. THE CONJUNCTIVA. 75 Fig. 41. {Scemisch.) Section of a trachomatous eyelid. a. Muscle :, h h, Tarsus having undergone fatty degeneration ; c, Atrophied Meibomian Grland ; d d, Hypertrophied Papilla ; e, Cica- tricial Tissue in the conjunctiva ; /, Tarsus. Pannus {Lat. a cloth rag) presents the appearance (Fig. 40) of a superficial vascularisation of the cornea, with more or less diffuse opacity, and often small infiltrations. The new vessels can be seen to grow in from the conjunctiva. It invariably com- mences in the upper portion of the cornea, extending generally over the upper half, and fre- quently remains confined to this region. But in many cases, at a later stage, it extends over the whole surface of the cornea ; this latter occurrence often takes place almost suddenly, and the vascularisation and opacity sometimes become so intense as to present quite a fleshy appear- ance, completely hiding the corresponding part of the iris from view. Histologically, pannus consists of a new growth, which is extremely rich in cells, and which closely resembles the con- junctiva when occupied with confluent granulations. It is in fact a vascular granulation tissue, which grows in from the limbus, and is situated between the corneal epithelium and Bow- man's layer. After a length of time Bowman's layer becomes destroyed in places, and then the cellular infiltration gains access to the true cornea, and gives rise to permanent changes in its transparency and curvature. In some bad cases of old-standing pannus the latter undergoes a connective-tissue change. It then becomes smooth on the surface, and the vessels almost disappear, so that the cornea is covered with a thin layer of connective tissue, which obstructs the passage of light and is not capable of cure. Small ulcers, and sometimes white deposits, are liable to form at the lower edge of the pannus near the centre of the cornea. These deposits are superficial, and can be easily scraped off. Another result of pannus, sometimes seen, is a bulging or staphy- lomatous condition of the cornea, the tissues of which have become 76 DISEASES OF THE EYE. [chap. m. so altered and weakened that they give way before the normal intra-ocular tension. A pannns in which as yet there is no connective-tissue alteration, and where there is no staphylomatous bulging, is capable of under- going cure without leaving any opacity behind, except that which may be due to ulcers that have been present. Pannus is generally accompanied by photophobia and ciliary neuralgia. It may come on at any stage of the disease, and causes defective vision, in proportion to the degree and extent of the opacity. Severe pannus is liable to induce iritis. It was for a long time held that pannus was due to mechanical irritation, caused by the rough palpebral conjunctiva ; but even severe pannus is often seen with a comparatively smooth conjunctiva, while with a truly rough conjunctiva the cornea is frequently perfectly clear. There can now be little doubt that pannus is analogous to the granular disease in the conjunctiva. It is, in fact, the same disease modified by reason of the different tissue in which it is situated, this different tissue being itself a modification of the con- junctiva ; and microscopic examination of the bulbar conjunctiva shows that it is infiltrated though apparently unaffected on clinical inspection. So that pannus is a direct extension of the disease to the cornea. Visible follicles in the bulbar conjunctiva are extremely rare ; we have however seen a neglected case in which the patient refused all treatment, and not only were there follicles on the bulbar conjunctiva, but also on the cornea. Prognosis. — At any period prior to cicatrisation of the con- junctiva an attack of purulent blennorrhoea is liable to come on. If not too severe, this may result in a cure by absorption of the trachoma bodies, and should not be checked. If, however, the attack be very severe, the eye runs dangers similar to those of an ordinary attack of purulent conjunctivitis. These dangers are less the more complete and the more intense the pannus. On the whole, if the disease come under care at an early period, and if treatment be carried out strictly, vision will be retained in a majority of cases, although a radical cure may be difficult or impossible. Patients require to be under constant treatment for long periods, and the very lengthened time, and steady continuous treatment needed for a cure, are probably the main obstacles to that cure. In most cases of chronic granular ophthalmia, attend- OHAP. iii.l THE CONJUNCTIVA. 77 ance three times a week for a year will be required, to effect any- thing that can be called a cure. The common experience is that patients attend for some weeks, and then, being very considerably relieved of their distressing symptoms, and finding their sight vastly impi'oved, they cease attendance long before the disease has been eliminated, to return after a brief interval with a condition of things as bad as, if not worse than, before. It is therefore desirable at the very outset of treatment to explain the tedious and dangerous nature of the ailment to each patient. Treatment. — The aim of this is to bring about the absorption or disappearance of the trachoma bodies with the greatest possible despatch, in order to prevent the destruction of the mucous mem- brane, to which they tend. The methods of treatment on which most reliance is placed, either separately or in combination, are : — the application of caustics, mechanical or operative procedures, and the use of jequirity. In conjunction with these, cases attended by inflammatory symptoms and discharge must be treated according to the general principles indicated on p. 54, and antiseptic lotions or sterilised fluids should be used to keep the conjunctiva free from discharge, and a simple ointment should be applied to the eyelids at night. Complications may require to be dealt with by special methods. Attention should be paid to the general health of the patient, and to the hygienic conditions under which he lives, and finally prophylactic measures should be taken to prevent the spread of the disease to other members of the household or community. I. Caustics. — No caustic application should be made with the object of directly destroying the trachoma bodies, for this can be done only at the expense of the mucous membrane around them. The most useful caustics are nitrate of silver and sulphate of copper. For chronic cases, with but little swelling of the papillae (blen- norrhoea), and with little or no cicatrisation, the best application is the solid sulphate of copper lightly applied to the conjunctiva, especially at the fornix ; but when there is considerable papillary swelling or discharge, a 2 per cent, solution of nitrate of silver, or a light application of mitigated silver nitrate, neutralised with salt solution, is to be preferred, Should there be ulcers on the cornea, or much inflammatory irritation of the eye, sulphate of copper should not be applied to the conjunctiva. An interval of twenty-four 78 DISEASES OF THE EYE. [chap. in. hours at least should be allowed to elapse between each application, whether of sulphate of copper or nitrate of silver, and cold sponging for fifteen minutes should be employed immediately after the application. A change of treatment will be occasionally required, even if the remedy first used answer well in the beginning, and one or other of the following can be adopted. Pure liquefied carbolic acid has been used with good result, but we have no experience of it. It is applied w^ith a camel's-hair pencil, and the excess washed off with plain water. Solution of sublimate, 1 in 1000, or even 1 in 500, may be applied with lint or cotton-wool to the everted con- junctiva with some pressure and rubbing. Alum, in the solid form, is also used in the same way, and in the same class of cases, as sulphate of copper. Ointments of copper sulphate (J to 1 per cent.) or copper citrate (10 per cent.) are sometimes employed, but they are not so active as the crystal. Sulphate of zinc is indicated if, as is sometimes the case, angular conjunctivitis be present as a complication. 2. Mechanical and Operative treatment. — The best of these pro- cedures are : expression, which aims at evacuating the granulations, and excision of the fornix, by which those situated in that region are removed en masse. Expression was formerly practised by the late Sir William Wilde of Dublin, who squeezed out the granulations between the thumb nails. The present-day proceeding is carried out aseptically by means of Knapp's roller forceps, or better still Fig. 42. with Graddy's forceps (Fig. 42). Similar but smaller instruments are also made for the purpose of reaching the inner and outer angles of the lids, where it is difficult to apply the larger ones. The opera- tion is very painful, and general anaesthesia may be necessary. The retro-tarsal fold of the everted lower or upper lid is grasped as far back as possible between the blades of the instrument, com- pressed and drawn upon, and in this way the trachomatous tissue is squeezed out with little or no laceration of the conjunctiva. The CHAP. III.] THE CONJUNCTIVA. 79 instrument has to be re-inserted and a neighbouring part of the conjunctiva treated in the same way, and so on, until the whole conjunctiva of each affected eyelid has been operated on. The four eyelids may be manipulated at one sitting, and the evacuation should be as complete as possible. Particular care should be taken to reach the part of the conjunctiva which is hidden under the commissures. Some cases are immediately and permanently cured by this operation ; while others, although greatly benefited, will still require further routine treatment with local remedies. Ex- pression is indicated only where trachomatous substance can be pressed out. Our experience with this method leads us to regard it as a very useful one for the acceleration of the cure of recent cases, some of which we have seen to recover with scarcely any trace of scarring. We often apply silver nitrate immediately after expression. Excision of the upper fornix of the conjunctiva also renders great service. This method shortens the treatment of all forms of the disease; the granulations in the palpebral conjunctiva, although not directly included in the operation, disappear quickly, and recurrences of the disease are rarer than by other methods of treat- ment. The resulting linear cicatrix has no serious consequence, and is as nothing when compared w4th the extensive cicatricial degenerations of the whole mucous membrane which the operation is calculated to prevent. In order to avoid cicatricial contraction care should be taken, during the operation, that sufficient mucous membrane be left to completely cover the globe when the patient looks down. Supplemental treatment with the customary local applications is employed until the cure is obtained. We find this an exceedingly useful procedure in some cases. When the tarsus is much thickened, partial or complete excision, including the con- junctiva over it, should be performed. Other mechanical methods are : scarification, scraping with a sharp spoon, brushing the conjunctiva with a metallic or stiff tooth- brush, followed by a rubbing with (1 in 500) solution of corrosive sublimate, electro-cautery, and electrolysis. 3. Infusion of Jequirity {Abrus precatorius, Paternoster Bean) is made by macerating 154 grains of the decorticised jequirity seeds in 16 oz. of cold water (a 3 per cent, infusion) for twenty-four hours. Twice a dav for three davs the lids are everted, and the infusion 80 DISEASES OF THE EYE. [chap. hi. thoroughly rubbed into the conjunctiva with a bit of lint. The result is a severe conjunctivitis with a somewhat croupous tendency (even the cornea being often hidden by the false membrane), accom- panied by great swelling of the eyelids, much pain, and considerable constitutional disturbance, rapid pulse, and temperature of 100°, or more. At first the pannus becomes more visible, but as the inflammation subsides, it diminishes or even disappears, while com- plete cure of the granular ophthalmia itself is rarer. Iced compresses to the eyelids may be used during the inflammation. A fresh infusion (not more than seven days old) must be employed in order to secure the best reaction. We find the remedy harmless, if not always successful ; but a good many cases are on record where violent diphtheritic conjunctivitis, followed by blennorrhoea of the conjunctiva, and by more or less extensive ulceration of the cornea, and even complete loss of the eye, were produced. We have, occasionally, seen small superficial ulcers form on the cornea without further injury. The presence of a purulent discharge from the conjunctiva is a contra-indication for this treatment, which is then liable to increase the intensity of the blennorrhoea in a dangerous degree. Cases where there is little or no papillary SAvelling, but merely dry trachoma with pannus, are the most suitable for its use, and we cannot recommend it too highly in these cases. Very rapid and effective cures of the severest pannus sometimes follow the use of this remedy in properly selected cases. But the presence of well- marked pannus of the cornea without ulceration is the only thing that can render the employment of jequirity justifiable, and in addition to this, as stated, the conjunctiva should be free from blennorrhoea. The occurrence of acute dacryocystitis is said to form an un- pleasant complication of the jequirity treatment, even in cases in which the sac was previously quite normal ; but we have never seen it to occur. In our opinion the danger of jequirity ophthalmia can be mini- mised considerably by taking care, when beginning the treatment, to allow twenty-four hours to elapse before making a second appli- cation. One can then gauge the degree of reaction, which is liable to vary with different infusions or Avith the idiosyncrasy of the patient. As a matter of fact, we have seen one patient who was absolutely immune to jequirity. CHAP. III.] THE CONJUNCTIVA. 81 Jequiritol, the active principle of jequirity, dissolved in glycerine and standardised experimentally, is sometimes used instead of jequirity. We have not found it as effective as jequirity, and it has the great disadvantage in hospital work of being very much more expensive. After the subsidence of the jequirity inflammation some of the local remedies, above referred to, should be regularly applied for the purpose of completing the cure of the conjunctival condition. 4. Treatment of complications. — Where pannus is present, an occasional drop of atropine should be instilled, in order to control the tendency to iritis ; but pannus in itself requires no special treat- ment unless it persists after the conjunctival disease has entered the cicatricial stage, when, as stated above, jequirity is of service. The operation of fefitomy may also be performed for pannus. It consists in the excision of a portion of the conjunctiva, about 5 mm. broad, around the corneal margin. Destruction of the vessels with the actual cautery we have also found to do good in the treatment of pannus. Ulcers of the cornea, if small, require no additional treatment beyond atropine ; but if severe must be dealt with accordingly. (See chap, v.) Sometimes small white spots resembling lead de- posits form in the centre of the cornea ; they are quite superficial, and can be easily removed with the point of a knife. Diplobacillary conjunctivitis is not a very uncommon complica- tion of trachoma, but when it occurs the patients do not always present the well-know^n appearances of angular conjunctivitis. In such cases sulphate of zinc relieves the acute symptoms considerably. If the upper lid be tightly pressed on the globe, as it sometimes is, the physiological lid-pressure varying in different individuals, an impediment is offered to the cure by any method, and pannus is promoted. It is then necessary to relieve the pressure by a canthoplastic operation. (See chap, xix.) The treatment of xerophthalmia, entropion, and such-like sequelse is described under their respective headings. Opinions differ as to the value of the treatment of trachoma by X-rays, radium, and high-frequency currents. Carbon dioxide snow is also being used at present. In addition to the local treatment it is of great importance that the hygienic surroundings of patients suffering from granular oph- 6 82 DISEASES OF THE EYE. [cnxv. in. thalmia be seen to, and that they be obliged to spend a considerable time daily in the open air. As regards Proj)hijlaxis, patients should be warned of the danger of infecting others. They should sleep by themselves in well- ventilated rooms, observe habits of cleanliness, and have separate towels, etc. Schools and public institutions should be inspected, and if there be any cases of granular ophthalmia present, an ex- amination should be made of all the inmates, and all persons affected with the disease as well as suspicious cases should be isolated. Follicular Conjunctivitis. — This is characterised by a catarrhal inflammation of a mild type, to which is added the presence in the conjunctiva of small round greyish or yellowish-pink follicles the size of a pin's head, which disappear completely as the process passes off, leaving the mucous membrane as healthy as they found it. The follicles are situated chiefly in the lower fornix of the conjunctiva, and may be discovered by e version of the lower lid, when they will be seen arranged in rows parallel to the margin of the lid. Whether they are easily discovered or not depends on their size and number, and on the amount of co-existing hyper?emia or chemosis of the conjunctiva. Follicular conjunctivitis usually attacks both eyes, and is a tedious affection, lasting often for months. It is met with chiefly in children, and most frequently in schools. Systematic examina- tions of the conjunctiva in schools have shown that a very large number of the children have follicles in the lower fornix, and occasionally they may be seen in the upper lids towards the angles. In some cases post-nasal adenoids are associated with them. The conjunctiva is otherwise normal, and in these cases the follicles produce no irritation or distress of any kind. To this condition the name " Folliculosis " is sometimes given, and it is believed that it renders the eye more liable to catarrhal infection. When this occurs, follicular conjunctivitis is the result. The existence of lymph follicles in the normal conjunctiva is disputed, and it is of course possible that, in cases in which they are found, their presence may be explained by the repeated but transient irritation, to which the conjunctiva, from its exposed position, is constantly liable. Considerable difference of opinion prevails as to the relation of this disease to trachoma, some believing that it is merely a mild CHAr. m.] THE CONJUNCTIVA. S3 or aborted form of the latter. The question cannot be definitely settled until the real nature and cause of these two affections are known. Clinically they seem to be distinct, and from our obser- vation in this country, where both are common, there are no practical reasons for regarding them as different forms merely of the same disease. The chief points of difference between them are : — Folli- cular conjunctivitis affects children, even in the upper-class schools ; trachoma occurs at all ages, but mostly in adults, and is confined to the lower classes. In follicular conjunctivitis the follicles are, with rare exceptions, confined to the lower lid ; they are more uniform in size and more regular in their arrangement than in trachoma ; furthermore they never produce cicatrices, pannus, or any of the ill effects which follow trachoma. The Symptoms are much the same as those of catarrhal con- junctivitis. Frequently there is little or no injection of the bul- bar conjunctiva, and the chief symptom is asthenopia — an inability to continue near work for any length of time — and much distress in artificial light. Causes. — These are much the same as in simple catarrhal con- junctivitis. The long-continued use either of atropine or of eserine is liable to bring on the disease. Treatment. — The most useful remedy in this troublesome affec- tion is an ointment of sulphate or citrate of copper of from gr. ss. to gr. ij in 3j of vaseline. The weaker ointments should be used at first, and later on the stronger ones if it be found that they cause no excessive irritation. The size of half a pea of the ointment is inserted into the conjunctival sac with a glass rod once a day. Eye- drops of equal parts of tincture of opium and distilled water are of use in some cases. Abundance of fresh air, with change from a damp climate or neighbourhood to a dry one, is of importance. If the use of a solution of atropine have induced the disease, it should be discontinued ; and if a mydriatic be still required, a solution of extract of belladonna (gr. viij ad gj) may be employed in its stead. In cases of folliculosis no local treatment is required. It may be well to add that no alarm need be created in a school on account of the occurrence of follicular conjunctivitis. The utmost that may be necessary is the separation of those cases in which there is much discharge, which might spread the catarrhal inflammation. 84 DISEASES OF THE EYE. [chap. hi. * Tubercular Disease oi the Conjunctiva.— This disease affects only one eye as a rule, and usually commences in the palpebral conjunctiva of the upper lid or in the upper fornix, and very rarely on the bulbar conjunctiva, in the form of a caseating ulcer, or as an inflammatory new formation of the granuloma type. The granular form occurs in the shape of small yellow or grey subconjunctival nodules, resembling miliary tubercles, or may result in the develop- ment of flattened outgrowths, cockscomb-like excrescences, or even pedunculated tumours. The margins of the ulcers are well defined, and their floors either of a yellowish lardaceous appearance, or covered with greyish-red granulations. The surrounding con- junctiva is swollen, and if the palpebral conjunctiva be much involved the lid becomes enlarged in every dimension, and the ulcerative process may soon destroy part of the lid. It is liable also to extend to the bulbar conjunctiva, and the cornea may become covered with pannus or affected with ulcerative keratitis. The preauricular and submaxillary glands are usually enlarged. The discovery of the tubercle bacillus would make the diagnosis positive, but as it not infrequently happens that the bacilli elude detection owing to their scarcity, while excised portions of the growths do not always show a typical tubercular structure, one of the various tuberculine tests, or inoculation experiments, may be necessary in order to remove all doubt. The application of one or more of these methods of diagnosis will serve also to distinguish this disease from secondary syphilitic ulceration of the conjunctiva, between which and the tubercular ulceration there is sometimes a resemblance. Moreover, in the syphilitic ulcer the detection of the spirochfcta pallida, or the application of ^Yassermann's test, would decide the diagnosis. The granular form of tuberculosis may sometimes be suggestive of trachoma, or even of a malignant growth. Tubercular conjunctival disease is usually unattended by pain, or there is only a slight burning sensation ; but, again, when the ulceration is extensive, severe pain may set in. The disease is very chronic, its progress sometimes extending over many years. It is rarely met with except in youth. Some of those whose eyes are attacked are already the subjects of tuber- culosis in other organs, but very many of them are perfectly healthy in that respect. In fact, there is reason to believe that tuber- culosis of the conjunctiva is much more often a primary disease, CHAP. III.] THE CONJUNCTIVA. 85 the result of an ectogenic infection, even in cases where already tuberculosis exists elsewhere, than of infection occurring through the blood. Tubercle bacilli introduced into the normal conjunctival sac have, it is true, been found to be harmless, for the intact epithe- lium offers an insuperable obstacle to their entrance into the tissue. But a superficial loss of substance of the conjunctiva is sufficient to allow of its inoculation with the bacilli, and then the disease becomes established. The frequent lodgment of foreign bodies under the upper lid explains why this is the situation in which the disease most commonly begins. But although conjunctival tuber- cular disease is not often secondary to tubercular disease in other parts of the system, yet it is itself liable to be the starting-point of general tuberculosis. Treatment. — The fact last mentioned makes it most important, in cases of primary tubercular disease of the conjunctiva, to thoroughly eradicate the diseased focus so as to avert infection of other organs, and this can often be effected. If the ulcers be not already too extensive they must be curetted, and the actual cautery freely applied. They may then be dusted with iodoform or lactic acid may be applied pure or in 50 per cent, solutions. An ointment of 4 per cent, picric acid in vaseline and lanolin, applied three times daily to the diseased area, has proved useful in some cases. Injections of tuberculin are also useful (see chap. vii.). Parinaud's Conjunctivitis. — This well-defined form of subacute con- junctivitis which may occur at any age was first described by Parinaud. With very rare exceptions it attacks only one eye. The chief features of the disease are : — The appearance of granulations or vegetations on the tarsal conjunctiva or fornices, with painful and considerable en- largement of the preauricular and neighbouring glands, on the same side as the affected eye ; the disease is ushered in with chills and malaise ; there is slight mucous, or fibrinous, secretion but no suppuration. The upper lid becomes swollen and perhaps nodular to the touch, and there is sometimes chemosis ; but the subjective eye-symptoms are slight. The granulations are red or yellowish, and at first semi-trans- parent, and they vary in size, being at times only as large as the head of a pin, while again they may even form polypoid growths. Small yellow granules and superficial erosions are often present, generally in the furrows between the large granulations. The glandular inflammation sets in along with, or immediately after, the eye-symptoms, and may end in suppuration. The sub-maxillary and sometimes even the cervical glands are affected. A complete cure results in the course of some months, without any corneal complication or subsequent scarring of the con- 80 DISEASES OF THE EYE. [chap. hi. junctiva. The last symptoms to disappear are the ptosis and glandular enlargement. Cause. — No case of the transmission of the disease to others has been observed. The theory of an animal origin, which was originally advanced, has not been proved. The histological changes, according to Verhoeff and Derby, consist in areas of necrosis in the subconjunctival tissue and extensive infiltration with lymphocytes, phagocytes, and plasma cells, but no suppuration. The deeper layers are in a state of clu-onic inflammatory reaction. The etiology is still uncertain ; in some cases inoculation experiments gave undoubted evidence of tuberculosis, while in others similar experiments failed. Verhoeff found a filamentous organ- ism (? leptothrix) in ten out of twelve cases. Some authors regard the disease as bovine tuberculosis. The only affections with which this disease is liable to be confounded are trachoma and tuberculosis. Treatment. — The disease tends to get well without treatment in the course of a few months. Various remedies have been tried, but simple antiseptic treatment is almost sufficient. The duration of the disease may be shortened by excision of any large granulations, on the applica- tion of the galvanocautery. If the glands suppurate, they should be opened. Ophthalmia Nodosa. — This disease is caused by the irritation (chemical or mechanical) of the hairs of certain kinds of caterpillars. The hairs give rise to ' foreign body ' granulomata, which appear as small nodules chiefly on the lower part of the bulbar conjunctiva. Both clinically and microscopically the condition bears a resemblance to tuberculosis, hence it has also been called pseudo-tubercular conjunctivitis. The presence of the hairs makes the diagnosis positive. In nearly all the recorded cases there was a history of caterpillars having accidentally come into forcible contact with the eye. The nodules are small, semi-translucent, and reddish or yellowish grey in colour. The disease is chronic, as the elimination or absorption of the hairs takes some time, but it terminates in complete recovery, unless the hairs have made their way into the iris, in which case a severe iridocyclitis may be set up. Sporotrichosis, due usually to the S. Beurmanni, also produces an irregular nodular appearance of the tarsal conjunctiva with superficial ulceration and little secretion or increased vascularity. The preauricular, and sometimes even the submaxillary glands become enlarged. Cultures or inoculation may be necessary to distinguish it from tuberculosis. Iodide of potassium in 10 to 20 grain doses is the best treatment. * Lupus of the conjunctiva usually occurs as an extension ol the disease from the surrounding skin, or rarely from the lacrimal sac. It is seen as a patch or patches of ulceration, covered with small dark-red protuberances or granulations, chiefly on the palpebral conjunctiva, which bleed easily on being touched. Like lupus of the skin, these ulcerations undergo spontaneous healing and cicatrisation in one place (unlike tubercular ulceration CHAP. III.] THE CONJUNCTIVA. 87 ill that respect), while they are still creeping over the surface in another direction. But it is now known that lupus, wherever it may occur, is a tubercular disease, and that the two forms differ only in their clinical aspect. Treatment. — Scraping with a sharp spoon, and the application of the actual cautery. Iodoform. Tuberculin. X-rays. * Syphilitic Disease of the Conjunctiva occurs both as primary and as secondary disease. It will be treated of in chap, xviii., on Diseases of the Eyelids. Ulcers of the Conjunctiva. — In addition to tubercular and syphilitic ulcers, the following conditions may lead to ulceration of the conjunctiva : — Injuries, foreign bodies, the separation of sloughs or membranes, pemphigus, epithelioma, smallpox ; phlyc- tens also appear as small superficial ulcers on the bulbar conjunc- tiva at one stage of their existence. * Spring Catarrh, or Vernal Conjunctivitis. — In this extremely chronic but rather rare disease, which, strictly speaking, is not a catarrhal affection, the tarsal conjunctiva of the upper lid is occupied by hard flattened bodies of a pale pinkish colour arranged close together, and known as tesselated or pavement granulations (Fig. 43). They are often slightly pedunculated. The conjunctiva assumes a milky- white opalescence. The bulbar conjunctiva becomes injected, slightly oedematous, and at the limbus somewhat elevated with hard, gelatinous-looking and nodular greyish swellings in which minute pale-yellow dots can often be seen (Fig. 44). The lower palpebral conjunctiva is often milky-looking, but never shows granu- lations. All these appearances may be present in the same case, or any one (the bulbar appearances, or the pavement granulations, or the milky- white opacity) or two of them may be absent. The margin of the cornea itself is apt to be invaded with a more or less circular infiltration resembling arcus senilis. Very occasionally the cornea becomes seriously implicated owing to the growth on the limbus extending over a great portion, or even over the entire cornea. There is a scanty mucous or muco-purulent secretion, and the patient may complain of the eyelids being stuck together in the morning, of difficulty of using the eyes for near work, of itching and burning sensations, and all these symptoms are increased by exposure to heat. The eyelids droop slightly, giving the patient a sleepy look. The condition of the upper lid might at first suggest granular 88 DISEASES OF THE EYE. [chap. hi. ophthalmia, from which it differs, however, in the solidity, absence of transluceiicy, and tesselated arrangement of the ' granulations,' which moreover do not attack the fornix. The pathological changes con- sist in connective tissue proliferation, hyaline de- generation of the subcon- junctival tissue, and proliferation of the epi- thelium, which sends solid or cystic processes into the stroma. It is still uncertain which of these is the primary change. The conjunctival secre- tion is very rich in eosino- phil cells, a point which cases. Fig. 43. — Spring catarrh. Upper lid everted. From sketch by L. W. would assist the diagnosis in doubtful The affection is chiefly met with in boys between six years of age and puberty, and is in most cases bilateral. The patients sometimes look anaemic, and have in many cases enlarged lymphatic glands. Blood changes are often present, and consist not so much in an absolute increase of the white corpuscles, as in a relative in- crease of lymphocytes. The disease makes its appearance rarely in conjunction with heat erup- tions on the skin, in warm weather in the late spring or early summer, and generally disappears, or is much modified, in the cool seasons, to re- turn again with the next warm season; and this is liable to go on for many years. In the intervals between the attacks the congestion and subjective symptoms disappear, but the other appearances persist until recovery sets in m Fig. 44. — Circuincorneal growth in spring catarrh. Sketched by L. W. This disease has been attributed to the action of strong light, CHAr. iii.l THE CONJUNCTIVA. 80 or to ultra-violet rays, but this is probably not the case. Although an occlusive bandage often produces a rapid improvement, this is not because of the exclusion of light, but on account of the protection from the air, for the same result is attained by the use of well-fitting goggles. We have recently seen a remarkably rapid improvement follow the use of motor goggles. Exposure to snow in high altitudes where the light is particularly strong is also beneficial owing to the cool atmosphere. The cause of the disease is really unknown. The Treatment of the majority of these cases yields unsatisfactory results. Airtight goggles should be worn. So far as possible all exposure to the heat of sun should be avoided. If possible the patients should reside in a cool place in the summer. Weak astrin- gent coUyria, or ointments, may be used ; or iodoform ointment (1 in 15), a little put into the eye once a day ; or massage twice daily in conjunction with yellow oxide ointment. Dilute acetic acid 1 or 2 minims to the 3J is also recommended. De Schweinitz recom- mends borogiyceride locally, and arsenic internally. Antipyrin and quinine internally have proved of use in some cases. Strong salicylic acid ointment (20 grs. — 5J) has been recommended, but we have tried it without much effect. Instillations of adrenalin have proved very beneficial in some cases, and good results have also been obtained with radium. It has been stated by one surgeon that removal of adenoids and enlarged tonsils cures most cases. Pemphigus of the Conjunctiva. — This is another rare disease. It has been seen in connection with pemphigus vulgaris of other parts of the body, but it also occurs as an independent disease. It is attended by attacks of much pain, photophobia, and lacrimation ; and the conjunctiva, at each place where subconjunctival exudation of serum has been situated, undergoes degeneration and cicatricial contraction. Such attacks succeed each other at shorter or longer intervals, for weeks, months, or years, until finally, the entire conjunctiva of each eye may have become de- stroyed and the eyelids are adherent to the eyeball or to each other. The cornea gradually becomes comjjletely opaque, or, having ulcerated, is rendered staphylomatous. In the course of the disease the eyelashes are apt to become turned in on the eyeball, or even entropion may follow. The lacrimal puncta and canaliculi may become obliterated and the cilia may disappear where the lids are adherent. The foregoing is a description of a severe case. In less severe cases the conjunctiva may not be completely destroyed, and the cornea may not be affected. Bullae are seldom seen, for the conjunctival epithelium is so delicate 90 DISEASES OF THE EYE, [chap. III. that the serous exudation beneath it- breaks it down at once. Conse- quently, the conjunctival surface is found in these cases to be covered by what looks like a membranous deposit, upon removal of which a raw surface is exposed. These appearances have led to the mistaken diagnoses of croupous and of diphtheritic conjunctivitis. Rarely deep- seated bluish cysts are present. They existed in the case illus- trated by Fig. 45. Treatment is helpless in re- spect of arresting the progress of the disease, or of restoring sight when lost in consequence of it. The most that can be done is to relieve the distressing symptoms by emollients to the conjunctiva, ^_ _ and, by the use of closely fitting j(MX fe W^'^'^ ^'^''T^^ goggles, to afford protection