Ophthalmology and ophthalmoscopy, for practitioners and students of medicine

Front matter

«s äu V

UNITED STATES OF AMERICA.

OPHTHALMOLOGY

Preface

THIS work principally subserves didactic purposes, and is intended to present modern ophthalmology in a form which will facilitate its reception. This requires above all a distinct separation— which should also be apparent externally — of the different divisions and subdivisions, and a gradually advancing presentation of the subject, that assumes as little as possible. This explains the introduction of the optical and anatomico-physiological data which are necessary to the comprehension of the subject. This appeared to me to be especially important in the chapter on errors of refraction and accommodation, whose mastery is impossible without such preliminary knowledge. As I know from experience the widespread antipathy of physicians to mathematics — it is difficult to determine whether this is congenital or acquired — I have reduced it to such a homeopathic dose, that even the student who most dreads calculations and formulae can tolerate it without bad effects.

The retention of the formula ->= - + t, which will suffice approximately in practice, will probably not give rise either to physical or mental strain. But this very knowledge of the errors of refraction will find an important application in medical work, when we finally discontinue the bad habit of simply sending patients to the optician for the purpose of selecting spectacles. This is somewhat similar to intrusting the apothecary with the treatment of patients. Examinations of refraction — in addition to the examination of vision and color blindness — also possess special significance for hygienists and military surgeons. I have therefore paid due attention, in the proper place, to their special needs.

Furthermore, a more detailed description has been devoted to ophthalmoscopy and everything belonging to this category, has been given, in order to furnish the student, within the limits of general ophthalmology, with a somewhat complete guide for use in

IV

PREFACE.

ophthalmoscopic courses. On the other hand, the operations have only been described in their salient features. What has been gained in this way, has been used to advantage in discussing other subjects. The expert reader will soon find that I have not alone written " according to distinguished authority," but that, in addition to the critical sifting of what has been handed down to us, I have also furnished much that is new in form and contents.

H. SCHMIDT-RlMPLER.

Marburg, October, 1884.

Preface To The Second Edition

The favorable judgment of specialists and the rapid sale of the first edition have shown me that the labor devoted to this work has not been useless. I have endeavored to keep it abreast of the times by improvements, and by the introduction of the most recent advances (such as the use of cocaine, more exact methods of measurement of the light sense, etc. >. The alphabetical index has been notably enlarged by the insertion of the general diseases, in so far as they are mentioned in the work.

H SCHMIDT-RlMPLER.

Marburg, April ist. 1886.

Preface To The Third Edition

THIS new edition has again been subjected to careful revision, It has been changed in accordance with the constant increase of our knowledge, and additions have been made. May its continued favorable reception permit the different editions of the work to follow the new acquisitions of ophthalmology, at not too long intervals.

H. SCHMIDT-RlMPLER.

Marburg. December 4th. 1887.

EDITOR'S PREFACE.

The task of editing the translation of Professor Schmidt- Rimpler's book has been an agreeable one. The work is a clearly written, comprehensive and scientific treatise, that cannot fail, I think, to secure the confidence of the profession in the Englishspeaking countries, as it has that of the Germans. I have at a few points added short notes, which I trust may not be considered to mar the symmetry of the original. A few illustrations, chiefly from Stellwag's treatise, the English translation of which is now out of print, have been added.

For the translation, which I believe, on careful comparison with the original, to be a faithful one, I can take no credit, since it was prepared for the publishers by a highly competent hand.

D. B. St. John Roosa:

New York, June 26th, 1! 20 East 30th Street.

Chapter II

A. General Part, ....

i. Optical Introduction, .

2. Physiological Optics, .

3. Refraction and Accommodation

B. Special Part, ....

Myopia, ....

Hypermetropia, Astigmatism, Anisometropia, .

Presbyopia,

Errors of Accommodation, I. Paralysis of Accommodation, II. Spasm of Accommodation - Tension,

94 96

Abnormal Accommodative

CHAPTER III. Amblyopia and Amaurosis

1. Diagnosis, ....

Central Vision,

Peripheral Vision, .

Light Sense, ....

Color Sense, ....

Daltonism, ....

Phosphenes,

2. Prognosis, Etiology and Treatment,

Special Forms of Amblyopia, Simulation of Amaurosis, Blindness, ....

CONTEXTS.

Chapter I

i. Theory of Ophthalmoscopic Examination

2. Various Forms of Ophthalmoscope, .

3. Source of Illumination,

4. Method of Ophthalmoscopic Examination

5. Focal Illumination, ....

6. Measurement of Refraction with the Ophthalmoscope.

7. Diagnosis of Differences of Level in the Ophthalmoscopic Image of

the Fundus Oculi,

PAGE

Chapter II

Ophthalmoscopic Appearances in the Healthy Eye, Anatomy of the Optic Nerve, Retina and Tunica Uvea, 1. Optic Papilla,

2. Retina,

3. Choroid,

186 186 194 198 201

CHAPTER III. Diseases of the Optic Nerve

Hyperemia of the Optic Nerve, .

Papillitis, Neuritis Optico-intraocularis, Choked Disk, Neuroretinitis (Neuritis descendens, Papillo-retinitis), True Inflammation of the Optic Nerve,

Atrophy of the Optic Nerve,

Excavation of the Optic Papilla

Tumors of the Optic Nerve,

Chapter IV

1. Hyperaemia and Anaemia of the Retina,

2. Retinitis Simplex (Retinita Serosa), .

3. Retinits Parenchymatosa,

4. Hemorrhage of the Retina — Retinitis Haemorrhagica,

5. Pigment Degeneration of the Retina (Retinitis Pigmentosa), .

6. Retinitis Proliferans,

7. Detachment of the Retina (Amotio s. Sublatio Retinae), .

8. Embolism of the Central Artery of the Retina (Ischaemia Retinae), Glioma Retinae,

Chapter V

1. Hyperaemia of the Choroid,

2. Exudative Choroiditis

3. Staphyloma Posticum, Sclerectasia Posterior

choroiditis Posterior, .....

4. Hemorrhages into the Choroid, Detachment of the Choroid

Conus, Sclerotico

230 230 235 239 241 244

245 250

256 256 256

261 263

CONTENTS. xi

PAGE

5. Rupture of the Choroid 264

6. Tuberculosis of the Choroid, ........ 264

7. Choroidal Tumors, 266

Chapter VI

1. Opacities of the Vitreous Body, . ,

2. Suppurative Hyalitis,

3. Foreign Bodies and Entozoa in the Vitreous,

4. Persistence of the Hyaloid Artery, Detachment of the Vitreous

268 269

273 278

Chapter I

A. Glaucoma, 285

1. Clinical History, 285

I. Glaucoma Simplex 287

II. Glaucoma Inflammatorium 290

III. Secondary Glaucoma, 292

2. Occurrence and Etiology, 294

3. Pathological Anatomy 295

4. Theory of the Pathogenesis and Nature of Glaucoma, . . . 296

5. Prognosis and Treatment, 301

B. Ophthalmomalacia .307

CHAPTER II. Diseases of the Lens, 309

Anatomy and Pathological Anatomy of the Lens, .... 309

I. General Diagnosis ; Ripeness, . . . ... . 311

II. Partial, Non-progressive Cataract, 314

III. Total Opacities of the Lens, 318

Visual Disturbances, . . . ... . . 320

Treatment 323

Cataract Operations, 325

After-treatment 336

IV. After Cataract ; Secondary Cataract, .... 338

2. Aphakia 339

3. Errors of Position, 34a

Chapter III

1. Hypersemia of the Conjunctiva, 345

Xll

CONTENTS.

Simple (Catarrhal) Conjunctivitis, ...... 347

Conjunctivitis Phlyctaenulosa (Conj.-scrophulosa, Exanthema-

tica ; Herpes Conjunctivae), ...... 350

Blennorrhcea. — Catarrh with Swelling. — Granulakons (Trachoma).— Follicular Conjunctivitis, 353

Pathological Anatomy and General Diagnosis, . . . 353

I. Conjunctivitis Blennorrhoica, . . . . . 358

Ophthalmia Gonnorrhoica, 366

Ophthalmia Neonatorum, 367

Membranous Conjunctivitis, 368

II. Catarrh with Swelling (Epidemic Catarrh), . . 369

Exanthematous Ophthalmia, - 369

III. Conjunctivitis Granulosa, Trachoma, .... 370

Ophthalmia Militaris (^Egyptica) 376

IV. Follicular Conjunctivitis 377

Diphtheritic Conjunctivitis, 378

Pterygium, 382

Xerosis Conjunctivae, . 385

Symblepharon, 386

Subconjunctival Hemorrhage (Hyposphagma). — Chemosis. —

Lymphangiectases, ........ 387

Syphilis. — Lupus.— Tuberculosis. — Amyloid 388

Injuries of the Conjunctiva 389

Tumors of the Conjunctiva, 390

III

1. Keratitis,

I. Circumscribed Superficial Affections of the Simple Corneal Infiltration,

Punctate Keratitis

Fascicular Keratitis, II. Formation of Vesicles upon the Cornea, Herpes Corneae (Keratitis Vesiculosa), Keratitis Bullosa, Purulent Affections of the Cornea, Circumscribed Purulent Infiltration of the Hypopyon-Keratitis, Keratomalacia, Keratitis Xerotica, .

Keratitis Neuroparalytica, Diffuse Infiltrations of the Cornea, Pannus (Keratitis Pannosa).

Diffuse Parenchymatous Keratitis, Scleritic Infiltration of the Cornea, Ulcers of the Cornea, Absorption and Reparative Ulcers Ulcus Rodens,

V. Cornea

Cornea,

415 420 420

CONTENTS.

Xlll

Annular Ulcers of the Cornea Keratitis Dendritica, Corneal Opacities,

Band-shaped Corneal Opacities,

Gerontoxon, ....

Changes of Curvature,

I. Cicatricial Staphyloma, II. Non-cicatricial Kerectasias, III. Flattening of the Cornea (Phthisis Corneas) Injuries to the Cornea, Tumors of the Cornea,

43° 430 432

CHAPTER V. Diseases of the Sclera

Anatomy, .

1. Episcleritis and Scleritis,

2. Ectasia and Staphyloma of the Sclera,

3. Injuries of the Sclera,

4. Ulcers and Tumors of the Sclera,

433 433 433 435 436 437

Chapter VI

1. Hyperaemia of the Iris, 438

2. Iritis, 438

I. Symptomatology, 438

II. Course and Terminations, , 442

Iritis Simplex s. plastica, \\\

Iritis Serosa 444

Iritis Suppurativa, 445

Iritis Condylomatosa s. Gummosa, ...... 445

III. Etiology, 446

IV. Treatment, .... 447

3. Motor Disturbances of the Iris, 450

4. Injuries of the Iris, .......... 451

5. Pseudoplasms and Foreign Bodies in the Iris and Anterior Chamber, 453

6. Congenital Anomalies, 455

7. Operations on the Iris, , . . . 455

CHAPTER VII. Sympathetic Affections. — Pur

Diseases of the Ciliary Body ulent Choroiditis,

1. Cyclitis,

2. Sympathetic Diseases of the Eye,

Enucleation. — Exenteration, .

Optico-ciliary Neurotomy,

Insertion of an Artificial Eye. — Prothesis Ocularis

3. Suppurative Choroiditis. — Panophthalmitis,

462 462 462

469 470 472 474

XIV

CONTENTS.

CHAPTER I. Diseases of the Ocular Muscles

A. General Part,

Physiological Action of the Ocular Muscles.

B. Special Part,

i. Paralyses of the Ocular Muscles, I. General Diagnosis, II. Special Diagnosis, . . .

III. Course and Termination, .

IV. Etiology, . .

V. Treatment, ....

2 Strabismus Concomitans (Muscular Squint) I. General Diagnosis, II. Special Diagnosis and Etiology, .

III. Course,

IV. Treatment,

Squint Operation,

3. Insufficiency of the Internal Recti. — Asthenopia,

4. Spasms of the Ocular Muscles. — Nystagmus,

PAGE

493 498

514 520

Chapter II

1. Diseases of the Bones, . 529

2. Inflammation of the Cellulo-Fatty tissue. Thrombosis of the Veins, 530

3. Exophthalmus. Basedow's Disease, 532

4. Tumors of the Orbit, 533

5. Injuries of the Orbit, 535

6. Congenital Malformations of the Eye 535

Chapter III

1. Diseases of the Edges of the Lids 539

I. Blepharitis Marginalis, 539

II. Hordeolum, 541

III. Distichiasis and Trichiasis 542

IV. Ankyloblepharon. Blepharophimosis 545

2. Diseases of the Integument of the Lid and the Tarsus, . . . 545

I. Chalazion 546

II. Tumors, 548

3. Anomalies of Position, 548

I. Entropium, . . 548

II. Ectropium, 550

III. Blepharospasm 552

CONTENTS. xv

IV. Ptosis. Lagophthalmus, . 553

4. Congenital Anomalies, 555

CHAPTER IV. Diseases of the Lachrymal Organs, ...... 556

1. Diseases of the Lachrymal Gland, 557

2. Diseases of the Lachrymal Excretory Passages, . . . . 558

I. Anomalies of the Lachrymal Puncta and Canaliculi, . . 558

II. Diseases of the Lachrymal Tube 558

Dacryocystitis, . 558

Dacryocysto-Blennorrhcea. Strictures of the Lachrymal Duct, 559

Part First. General observations on the examination and treatment of the eye

DISEASES OF THE EYE.

Chapter I. General Remarks Ox Examination Axd Treatmext Of The Eye

A. Examination of the Eye.

OPHTHALMOLOGY not only endeavors to save and improve the eyesight of the patient, but it also aids the sight of him who uses his eyes in the capacity of physician — he learns to see clearly and accurately. Almost all diseases of the eye are diagnosticated by the sense of sight; an ophthalmologist with poor sight would be at a great disadvantage. But in addition to the necessary acuteness and exercise of the sight and a knowledge of the morbid pictures, a correct method of examination is also required. As in the clinics for internal medicine, great importance is attached to taking the exact present condition, in which the entire body is subjected to inspection in a certain order, so that we may avoid overlooking or neglecting any symptom, so likewise a regular sequence must be carried out in examination of the eye. In both cases, however, the experienced observer may occasionally permit himself omissions and deviations.

We should begin with an inquiry concerning the symptoms which have led the patient to consult the physician. It is especially in diseases of the eye that this point is apt to be neglected, because a single glance sometimes informs us concerning the disease: at all events, the expression, "Yes, I know," would be more often justified here than in other diseases. Nevertheless, the complaints should be carefully listened to, particularly as the affected organ may be subjected at the same time to external inspection. The symptoms sometimes refer to entirely different matters than is supposed at the first glance. A patient with chronic inflammation of the lids, perhaps, does not consult us concerning this disease, to which he has become accustomed, but in order to have glasses prescribed. As a matter of course, excessive prolixity is to be checked.

The condition of the integument of the lids is first noticed, whether there is redness, eczema, or oedema. We notice further whether the lids can be raised easily and freely, or the eye remains entirely or partly covered by them. Attention is to be directed to epiphora or the escape of a watery, mucous, or purulent secretion which adheres to the angles of the lids or the cilia. By pulling gently on the lids, the appearance of the edge of the lid can be seen: whether it is sharp-angled and pale, or somewhat blunt and red, whether the lashes are present in normal number and what their position is. Not infrequently a few hairs rub against the globe, or the entire edge of the lid is directed against the eyeball (entropium). In other cases the edge is turned away from the globe, more or less to the outside, so that portions of the mucous membrane which cover the inner surface of the lid become visible (ectropium).

Special attention is to be paid to the puncta lachrymalia, particularly the lower one, which often turns outward and does not dip into the lachrymal canal. At the same time dilatation and hypersecretion of the lachrymal sac may be looked for by means of pressure with the index finger on the integument adjacent to the inner angle of the lids. If there is increased secretion of the mucous membrane of the lachrymal sac and occlusion of the lachrymal duct, fluid will be discharged from the puncta lachrymalia.

We then proceed to the examination of the eyeball itself. In some cases the eye cannot be opened on account of the swelling of the lids or, even apart from such swelling, it is kept closed spasmodically— a phenomenon which is not uncommon in children. Caution must be exercised in separating the lids, especially if f.g. i,-Desmarres' Elevator. we are unaCquainted with the condition of the eye, because an existing extensive and deep-spreading corneal ulcer may perhaps rupture on the application of force and even the lens may protrude. In such cases it is least dangerous to place a Desmarres' elevator (Fig. i) beneath the upper lid. The lid being slightly raised, the curved brass or tortoise-shell surface is allowed to pass between the lid and the globe, and the former is then drawn upward by placing the elevator against the upper edge of the orbit. The following method may be recommended in fixing the head in unruly children. Placing the feet upon a stool, we take a seat opposite the attendant, who holds the child upon his lap, and then place the child's head between our knees, while the attendant holds the hands and presses the legs against himself with his arm. In this way the

EXAMINATION AND TREATMENT OF THE EYE.

necessary examination may be made without special difficulty, and, in the case of children in arms, we are hardly able to effect our object in any other way.

We now notice whether the caruncles and conjunctiva bulbi are injected or swollen. An especial diagnostic significance as regards severe inflammatory processes attaches to the presence of a narrow, red vascular zone around the cornea, consisting of tolerably parallel small vascular twigs (so-called pericorneal or subconjunctival injection). When this is present, we never have to deal with

Fig. 2. — Lateral Illumination.

a simple inflammation of the conjunctiva. If the mucous membrane presents no pronounced changes (granulations or blennorrhcea), special attention must be directed to the cornea and iris. On account of the reflection of the cornea, small foreign bodies, patches, opacities, and ulcers are apt to be overlooked, and we must here strain our sight somewhat. How often are small particles of iron or coal upon the cornea overlooked ? If the changes are very delicate (as in the anterior chamber, on the iris, in the lens), so-called lateral illumination must be employed, the light being concentrated by means of a convex lens upon the spot to be examined. The

DISEASES OF THE EYE.

details of this important method of examination will be found in the chapter on ophthalmoscopy.

The curvature of the cornea, which acts like a convex mirror, is well shown by the image it reproduces of objects situated opposite. If the patient sits with his face turned toward a window, we will see distinctly the miniature image of the window and can infer an error in the corneal curve from an irregularity or distortion of the image. A more distinct image is obtained by the use of the keratoscope (Fig. 3). This consists essentially of a pasteboard or metal disk, upon which are drawn concentric black rings,

like a target. This disk is held in front of the eye of the patient, who sits with his back turned toward the window, and we then look, through the opening in its centre, at the rings reflected on the cornea. Distortion, resulting from irregular reflection of the cornea, is then very easily recog nized.

We then inspect the anterior chamber, its depth, i.e., the distance between the iris and lens on the one side, and the cornea on the other side, whether the aqueous humor is transparent or cloudy, whether blood (hyphaema) or pus (hypopyon) is visible in it. With regard to the iris, attention is paid to the color, especially in comparison with the healthy eye, the position, brilliancy, and structure of the tissue. Furthermore, whether the pupil contracts well to light, whether it is uniformly round or angular (as from adhesions to the capsule of the lens, posterior synechia), whether it is abnormally large (mydriasis) or small (myosis). A dilated pupil associated with marked inflammation of the eye occurs almost exclusively in glaucoma. As a matter of course, we must have previously excluded dilatation by medicinal agents, for example, atropine. The pupil is normally black. If there is a defect on the capsule of the lens or opacities in the lens itself (cataract), the pupil has a gray, white, or yellowish-brown color, either throughout or in circumscribed places. Artificial dilatation of the pupil is necessary in order to get a thorough view of the lens, its position, and of any

Fig. 3. — Keratoscope.

EXAMINATION AND TREATMENT OF THE EYE. j

opacities which may be situated peripherally; but this may be dispensed with, as a rule, unless the results of the previous examination and of the subsequent ophthalmoscopic examination render it probable that there is some anomaly of the lens.

The external objective examination of the eye is made thus far in this order. If the individual parts were examined in their consecutive order, the examination of the palpebral conjunctiva (the mucous membrane covering the lids) and of the transition fold of the conjunctiva palpebralis into the conjunctiva scleras, should have followed the examination of the conjunctiva bulbi. But it is well to leave this until the end of the external examination just mentioned, because the patients are apt to grow frightened and timid, the tears begin to overflow, and the eye reddens, on account of the inconvenience and pain connected with examination of the palpebral conjunctiva. Moreover, the lids should be everted with the greatest care — in order to avoid pressure on the globe — in cases of large, deep ulcers of the cornea, prolapse of the iris, and similar diseases. In the worst event, we must desist for a time from examination of the mucous membrane of the lids, especially of the upper one, whose eversion is the more difficult.

As a rule, the lower lid can be everted very easily. The patient is directed to look up, the index and middle fingers are placed upon the integument, immediately below the edge of the lid, and the latter drawn down until the mucous membrane turns out, and can thus be seen as far as the globe. In everting the upper lid, the patient is first directed to look sharply downward. This is extremely important to the success of the manipulation and we must make sure that the patient really does look down, because, upon grasping the lid or globe, there is a tendency to look up. With the thumb of the left hand, placed upon the lid immediately below the edge of the orbit, the lid and therefore its rim are raised somewhat from the globe, so that it can be grasped between the thumb and index finger of the right hand. The lid, which is grasped at the edge, not at the lashes, is now drawn somewhat downward, and, while the index finger of the left hand or a penholder, placed immediately below the orbital rim, presses the lid a little backward, is turned upon this fulcrum, so that the edge of the lid is brought against the upper edge of the orbit. The palpebral portion of the mucous membrane thus becomes visible. A view of the transition part to the globe, often requires still further elevation and posterior version of the rim of the lid, the patient being constantly directed to look downward. Resisting patients, who continually withdraw the head, must be seated in such a way that either the head can be held or can be supported against the chair or wall. With some practice, we can, as a rule, effect the desired object. This practice must be obtained, not alone in order to avoid hurting the patient, who will forthwith acquire distrust of the physician, on account of unskilful manipulation, but also in order that this examination may not be neglected on account of the consciousness of inability. Injection, irregularities, deposits, or foreign bodies must be looked for upon the everted mucous membrane.

After this external examination, the globe is palpated in order to ascertain its tension. Since the coverings of the eye are elastic membranes inclosing fluid contents, the tension will vary, as in a rubber bag filled with water, according to the relation between the contents and the size of the coverings. When the contents increase, the coverings will be stretched more firmly, and the eye will feel harder on palpation. This will also happen if the size of the capsule diminishes while the contents remain the same.

If, on the other hand, the coverings are large in proportion to the contents, or the latter are relatively small, the eye will feel soft. This examination, accordingly, will furnish data for determining the pressure which prevails in the interior of the eye and is exercised upon the walls from within. We therefore speak of the tension of the eye or of the amount of intraocular pressure. The harder the eye the greater the tension and intraocular pressure. Abnormal hardness is known as hypertony, abnormal softness as hypotony. The best way of testing the tension is to allow the eye to be gently closed, and then placing the index fingers on the upper lid to the inside and outside, to determine the hardness between the fingers by slight, alternating pressure. Palpation with one finger is less advisable because the globe is then readily pushed backward and in this way it is rather a test of the resistance of the orbital contents than of the eyeball. But we can often effect our object even in this way, by exercising very gentle pressure and avoiding displacement. Instruments (tonometers) have also been devised for the measurement of the tension (see Glaucoma).

It is also to be noted whether there is unusual prominence of the globe (exophthalmus) or deep sinking in (enophthalmus).

When the objective external examination of the eye is finished, before proceeding to internal examination with the ophthalmoscope or oblique illumination, it is usually advisable to determine the refraction and acuteness of vision of each eye separately. As a rule, both measurements are combined, the objects selected for the determination of refraction, by means of spectacles, being tables which contain letters or numbers in which, as, for example, in Snellen's and Schweigger's tables, the distance is also known at which they must be recognized by the normal eye. Hence, the relation of the patient's acuity of vision (V) to the normal is furnished forthwith.

In order to ascertain the power of accommodation, we first determine the near-point of the eye (punctum proxissimum). But inasmuch as the determination of the acuteness of central vision is insufficient, it is also necessary to ascertain the visual power of the peripheral portions of the retina, we must determine the visual field, i.e., the eccentric region in which, with constant central fixation of a point, sight is still possible. As a matter of course, the acuity of vision is not as great in the peripheral regions as in the central portion. This examination is most simply made by directing the patient to look closely at the pupil of the physician's eye, which is situated opposite. When the distance between the fixed and fixing eye is about 50 cm., the physician moves his hand from the periphery toward the centre, in a plane which is situated at right angles to the middle of the line connecting both eyes. As soon as the patient states that he sees the hand, the boundary of his peripheral field of vision is reached. Whether this corresponds to the normal may be determined by a comparison with the surgeon's own eye, since in this examination the examiner (whose other eye is naturally closed) must see the approaching hand at the same time as the patient, if the field of vision has the uniform normal extent. If the patient does not see the hand until later, he suffers from a contraction of the field of vision which, according to its position, is called a defect above, below, etc. In these tests we should be careful that the patient does not turn his eye directly upon the approaching hand, but continues the central fixation on the physician's eye. For accurate measurement of the field of vision and eccentric vision we employ certain instruments (perimeter) (see Amblyopia and Amaurosis).

This examination is followed by a test of the color sense and the light sense. WTith regard to the latter, we will simply mention here that there are diseases of the eye in which the normally lessened acuteness of vision on lowering of the illumination diminishes in an entirely abnormal, and unusually high degree. After each eye has been examined separately in this way, the co-operation of both eyes with regard to accurate convergence upon the fixed object, to mobility and binocular vision is ascertained (see Diseases of the Ocular Muscles).

In order to prevent injury to the eye from the strain, if there are notable signs of inflammation, the above-mentioned examinations should not be prolonged too far, and we must be satisfied with somewhat less exact results. Indeed, certain tests must be omitted if they are not directly necessary to our judgment of the case. If exactness in examination can only be attained by injury to the patient, the choice will not prove difficult to the conscientious physician who does not regard his suffering fellow-creatures as exactly synonymous with " clinical material." Such considerations should guide us in making an ophthalmoscopic examination. While a hasty glimpse will hardly cause any bad effects, even if the eye is very much inflamed, prolonged examination must be avoided.

In examination with the ophthalmoscope the light is, at first, simply thrown into the eye and the patient directed to look up and down, to the inside and outside. If there are opacities of the cornea, lens, or vitreous humor, we will then see darker shadows appear upon the red fundus. Their position is shown by oblique illumination, by means of which we can directly recognize opacities of the refracting media, even in the lens and the adjacent portions of the vitreous humor. With the interposition of a convex lens we then examine with the ophthalmoscope the fundus of the eye, in the inverted image (see Ophthalmoscopy); first, the entrance of the optic» nerve (papilla optica), then the macula lutea, and other parts. As the enlargement in the inverted image of the fundus, which is thrown by the interposed convex lens, is less than that in the direct image (in which the fundus is simply looked at through the refractive media of the eye which act as a magnifying glass), in order to gain a more rapid oversight, it is better to employ the former method before the latter. Finally, the refraction is determined objectively with the ophthalmoscope.

With such a methodical examination of the eye and its functions, there is not much risk of overlooking important data. If the morbid symptoms and the disease are recognized, it remains to ascertain whether and to what extent, a connection of the affection of the eye with special morbific influences, or with anomalies of the general constitution, is demonstrable. Here the general medical education comes into play. Without this foundation there can be, in many cases, no thought of a successful and appropriate treatment of the disease of the eye. It is to be hoped that the time will soon pass in which the public may ask, whether the ophthalmologist is also a physician. Very often the disease of the eye is the direct cause of the recognition or proper interpretation of other diseases. I will merely remind you of the connection between neuralgias and errors of refraction, of the significance of diseases of the optic nerve and ocular muscles in affections of the brain and nerves, and of the not uncommon cases in which the patient visits the physician on account of impaired vision, and the examination reveals an inflammation of the retina as the result