Diseases Of The Retina
Diseases Of The Retina.By LUCIEN HOWE, M. D.,
OF BUFFALO, N. Y.
Congenital Peculiarities of the Retina. As it is often difficult to define the limit between health and disease, it becomes an important question to determine what should be considered a normal retina. Therefore attention is first directed to those congenital peculiarities which cannot be classed as pathological. These are usually described last in chapters on the retina, but some repetition and confusion are avoided if they are considered first.
Such variations from the normal type are to be seen (1) in the vicinity of the optic nerve; (2) in the retina; and (3) in the macula.
First. Variations near the nerve are due to
- Insufficient pigment, which should not be confused with the actual atrophy of the retina and choroid in the vicinity of the nerve. The latter diseased condition shows itself as a crescent more or less marked, or even as a complete white circle (see Fig. 136).
- Excess of pigment may be seen in brunettes, and sometimes amounts to a dark, well marked ring of deposit about the nerve.
- Absence or abundance of blood vessels at the edge of the nerve may simulate disease and yet be within normal limits.
- Opaque nerve fibers may present an appearance which at first glance may be mistaken for neuro retinitis. It is well to bear this in mind in connection with that disease (see also pages 189, 190, 194).
Second. Variations in the retina are due to
- Insufficient Pigment. When of slight degree this gives rise to a peculiar appearance in which the vessels of the choroid simply become unusually prominent. When, however, pigment is lacking entirely, as in albinos, a network of vessels distributed over a pink or an absolutely white field is apparent.
- Excess of Pigment. In this condition the fundus is not only dark and the vessels difficult to distinguish, but occasionally the pigment is unequally distributed, giving rise to a peculiar mottled appearance. In some of these cases the choroidal vessels are particularly prominent, manifesting themselves as red lines distributed over rather a dark field. Any of the above variations from the usual type are easily recognized as physiological, unless the diminution or excess of pigment is confined to a certain part of the retina, when it may give to the fundus an appearance which is readily mistaken for an abnormal condition.
In typically normal eyes nothing can be seen of the macula except the red reflex of the fundus, the area usually being darker than the rest of the background and uncrossed by retinal vessels. But there are variations from this which should be noticed. In blonds and in retinas having an unusually small amount of pigment the macula can often be distinguished as a light spot on a darker field, its edges being well defined, or, again, as a dark area, the edges of which blend imperceptibly with the red of the retina near it. The latter is the more common form. In exceptional cases the macula is dark, and its edges are marked by a ring (macular reflex), the center being then light or almost white (reveal reflex) (see also page 188).
Small, white, glistening dots are occasionally found in the vicinity of' the macula. These are known as " Gunn's dots." Sometimes they are quite numerous, but they do not interfere with perfect vision. They are to be taken into account in making a differential diagnosis in cases of commencing albuminuria.
A simple and easy plan of studying the diseases of the retina is to begin with disturbances of the circulation First, when the supply of blood is diminished, as in anemia, or entirely shut off, as in embolism ; and second, when the supply is simply increased, as in hyperemia, or increased with other signs of inflammation. This will lead to the consideration of the various forms of retinitis, after which will follow a description of degenerative changes.
Anemia of the retina means properly that the lack of blood is merely the local expression of a general condition, while ischemia indicates that the causes of the altered circulation are in the eye itself.
. Retinal anemia occurs in ordinary syncope or from any cause as, for example, vaso motor spasm which contracts the arteries of the brain or lessens the amount of blood sent there. Retinal anemia, with contracted arteries, may occur in migraine, and may be associated with hemianopic blindness.
Symptoms. While very marked decrease or increase in the blood supply of the retina can be distinctly recognized, it must be admitted that the slighter variations from the normal standard are not easily diagnosed. However, the contracted vessels, the lighter color of the retina, the unusual whiteness of the nerve, and the functional disturbances, if present, tend to establish the diagnosis.
Treatment should be directed to the removal of the cause producing the general anemia. As strychnin has long been used hypodermatically for a diminished supply of blood in the optic nerve, as in atrophy, so has it been suggested for the same reason in retinal anemia. Nitrite of amyl may be used to relieve spasm of the arteries of the retina. A method of treatment well worthy of trial is to arrange the position of the patient, for as long a time daily as can be borne comfortably, so that the bead is lower than the rest of the body. The contracted or emptied vessels of the retina are filled by the force of gravity.
Embolism of the Central Artery of the Retina. Etiology. The most frequent cause of embolism is valvular disease of the heart, especially when complicated with fresh endocarditis. It also occurs with various forms of arteritis, with aneurysm of the aorta and carotid, with Bright's disease, and with pregnancy; occasionally it complicates chores. It may occur at any period of life, and has been recorded from the fifteenth to the eightieth year. Simultaneous embolic plugging of the central artery in each eye has been described, but it is an exceedingly rare condition. It is more frequent on the left than on the right side, and has occurred more times in men than in women.
Pathological Anatomy. In the earliest case observed with the ophthalmoscope (von Graefe) an opportunity was afforded to secure a postmortem examination one and a half years later (Sebweigger). Sections of the eye showed that the central artery was completely blocked just behind the lamina cribrosa. The embolus may he granular in nature, or consist of a hyalin plug, or may be covered with layers of endothelium. Sometimes it only partially blocks the lumen of the vessel; at other times it completely occludes its caliber. Atrophic changes may be found in the retina, the optic nerve, and the choroid, according to the date of the examination after the embolus has occurred.
The clot does not always block the central artery itself, but may lodge in one of the branches of the main retinal artery, and there produce over a limited area the. same symptoms, the same appearance, and the same pathological conditions which are found when the central artery is affected.
Re establishment of the circulation may occur because the lumen of the blocked vessel again becomes free, and the presence of' cilio retinal vessels may be the means of preserving good acuity of central vision. According to Ward Holden, with single embolism of a branch of the central retinal artery there may be a field of irregular form which to a considerable extent is explainable by variations of the arterial distribution, and in cases where the lumen of an artery remains blocked there may be a collateral restoration of its circulation by anastomosing vessels.
Symptoms. The patient may be entirely ignorant of the existing condition if the embolus occurs in one eve only, for there is no special pain or other peculiarity following, which calls attention to the difficulty, except the loss of vision, which occurs with characteristic suddenness. In other cases, however, the subjective symptoms in the form of a species of aura are peculiar. There are scintillations before the eye , or dark rings appear. In a very typical case which the writer observed the patient remembered peculiar flashes which called her attention to the rapidly departing vision.
The ophthalmoscopic picture is quite characteristic, being that of an almost pure and well marked ischemia, of the retina. The arteries are small, and the corresponding veins considerably reduced in size, or they may reveal unequal distention, the terminal endings of both being to a great extent lost. Pressure from before backward causes a regular current to flow through the vessels, which consist of broken cylinders of blood separated by clear spaces, moving sluggishly along. In the veins, directly after the lodgement of the embolism, an intermittent blood stream is often visible. The optic disk is blanched almost as it appears in atrophy, and the retina, especially in the neighborhood of the papilla and the macula, is of a whitish appearance (the so called fog like edema), in marked contrast with that of the other eye. A very characteristic feature of' this disease is the color of the macula. The rest of the retina may appear of a normal color or even decidedly whitened, but the macula stand; out in contrast with its surroundings as a clear cherryred spot which attracts attention at the first glance. The reason for this peculiar color is by no means fully explained. The general conclusion, however, is that it is not entirely an extravasation, but is due partly to an engorgement of the choroidal vessels beneath the macula, and partly to the effect of contrast which this spot then presents to the neighboring retina (Loring). There are also changes in the pigment epithelium. In darkskinned races the cherry spot may be replaced with a coal black one. This macular appearance is more apt to arise in stoppage of the main trunk than when only a branch is plugged. Occasionally, if the embolus lodges in a branch of the main artery, it is visible to the ophthalmoscope as a small yellowish body, or it may be assumed to be present because at one point in the artery there is a swelling, while beyond it the vessel is obliterated or greatly contracted. In the course of several weeks, in complete cases, the retinal edema subsides, the disk undergoes atrophy, and the vessels are converted into white lines.
The subjective symptoms are, in complete cases, sudden loss of vision, unless the presence of a cilio retinal vessel permits the preservation of good acuity of sight, as reported by Wadsworth, and occasionally headache and giddiness. According to C. F. Clark,' the evidence is not sufficient to warrant the conclusion that true cilio retinal vessels are the means of preserving the integrity of the papillo macular region of the retina. In obstruction of a branch, vision may be very good, or, indeed, even normal. The field of vision depends upon the extent of the circulatory obstruction. If only a branch has been occluded, that portion of the retina which receives its blood supply from this source will be paralyzed and the opposite area of the field darkened. Occasionally there is a central scotoma. The tension may be raised, lowered, or normal.
Diagnosis. These cases may simulate anemia of the retina, because the condition of the heart produces some general anemia, but the history is usually sufficient to separate one disease from the other. While the ophthalmoscopic appearances already detailed indicate interruption of the retinal circulation, it is often difficult, and even impossible, to distinguish between thrombosis and embolism of the artery. Similar appearances may be produced by hemorrhage into the sheath of the optic nerve (see page 453).
. This depends upon the rapidity with which the collateral circulation is established, a greater or less tendency to this being apparent almost from the first. In complete embolism of the central artery the prognosis is most unfavorable.
Treatment. Paracentesis has been tried in order to change the amount ,of blood pressure, but in general more depends upon improving the condition which has caused the embolus than upon any attempts at local medication. Nitrite of amyl inhalations are recommended by Gifford, and massage of the eyeball, in the hope of dislodging the embolus, should be faithfully tried. This has been effected in some cases.
Thrombosis of the Retinal Artery. Thrombosis may occur under the same conditions which are active in the production of embolism, and the thrombus may form either in the central artery itself or in one of its branches.
, it is difficult or impossible to distinguish between thrombosis and embolism. According to Priestley Smith, previous attacks of temporary blindness in the affected eve, a simultaneous attack of temporary blindness in the unaffected eve, giddiness, faintness, and headaches are apt to be associated with thrombosis, and not with embolism.
The treatment is the same as that recommended for embolism.
Hyperemia of the Retina. By this term is understood an abnormal and equal increase in the amount of blood throughout the entire retina. Hyperemia of the larger blood vessels is easily recognized. When, as is usual, this is accompanied by capillary hyperemia, the condition is indicated by a change in the color not only of the retina itself, but especially of the surface of the optic nerve, which becomes redder than normal. Should the hyperemia exist in a marked degree, the overflowing arteries have a tortuous appearance, such as would naturally be expected when an elastic vessel is filled beyond its normal capacity. Two forms of hyperemia are to be distinguished the active and the passive.
1. Active hyperemia may be produced by a variety of causes. One of these, for example, is long continued effort at accommodation, especially when made by artificial light or when the refractive condition of the eye necessitates an unusual amount of straining of the ciliary muscle. De Wecker has noticed that a solution of the tincture of opium dropped into the conjunctival sac will also produce a certain amount of active hyperemia. It is commonly present in eyes exposed to glare of light and heatable. g. in puddlers. The same condition occurs in several of the inflammations of the eye, especially when the uvea is involved.
Symptoms. These are more or less pronounced, varying from slight sensations of discomfort to considerable photophobia and lack of eyeendurance.
Diagnosis. This is not so easily made as might be imagined. As the subjective symptoms, even if present at all, are usually by no means prominent, the diagnosis in a large proportion of cases must be determined by the ophthalmoscopic appearance. But it should be borne in mind that the bloodsupply to the retina may seem to vary from the normal standard when in reality this is not the case. In some individuals the retinal vessels are much more abundant than in others, just as we find complexions of a florid type or with decided pallor. Particularly does the condition of the refraction change the apparent size of the vessels when examined by the ophthalmoscope. Again, a decided astigmatism may distort the vessels in different meridians. Indeed, the beginner with the ophthalmoscope must be careful not to fall into the common error of diagnosing a 11 retinal congestion " when, in reality, there is nothing of the kind present. Only a careful study of the case, with due regard to errors of refraction, will enable one in certain instances to decide as to the presence or absence of hyperemia of the retina.
2. Passive Hyperemia. Any cause which interferes with the egress of blood from the eye may produce this condition; for example, in glaucoma, where, as a result of the pathological condition accompanying that disease, the veins are enlarged to a considerable degree, the finer branches are more numerous, and the larger trunks more tortuous, especially near the margin of the papilla. Another example is furnished by the condition known as “choked disk." Stasis hyperemia is also present in mitral disease, emphysema, convulsive seizures, and, indeed, in any state which prevents the veins of the head and neck from emptying their contents into the various channels of the chest.
Symptoms. These are similar to those which occur in active hyperemia. The same care should he exercised in making the diagnosis, although in this form, mistakes are not so liable to occur as in active congestion.
The prognosis and treatment depend upon the causes.
Somewhat analogous to congestion or hyperemia of the retina is the condition known as hyperesthesia of the retina, or, to employ the term suggested by Jaeger and Loring, irritation of the retina.
Ophthalmoscopically, may be seen undue redness of the nerve head, veiling of its nasal margins, and delicate edema of its surface. Often the entire fundus is ill defined, and the details of the background of the eye are imperfectly seen.
Etiology. Cases of this character are caused by errors of refraction and anomalies of muscle balance. They are often associated with chronic headache, neuralgia, and their subjects suffer from photophobia, blepharospasm, and marked asthenopia. In some instances there appears to be a distinct relation between retinal irritation and changes in the naso pharynx, particularly those characterized by a hypersensitive mucous membrane and vaso¬paretic and infiltrated turbinals. Loring believes that retinal irritation may be a forerunner of organic optic nerve disease.
Anesthesia of the Retina (Neurasthenic Asthenopia). This condition is really a symptom of a complicated neurosis rather than a special disorder of the retina. Its phenomena have been specially studied by Wildbrand, who records the subjective symptoms as follows: Peculiar contraction of the field of vision ' indicating retinal fatigue and the development of the so called counter field (see page 486); rapid disappearance from view of any object which is fixed; diminution of central vision; sudden attacks of obscuration of vision and processions of scotomas; visual hallucinations; lack of fixation of the optical memory images; and marked asthenopia. The subjects of this affection are chiefly women, and often those afflicted with ovarian and uterine disease, hysteria, and chlorosis. Pure types are also seen in men, and are often connected with sexual derangements.
. This must be directed toward the general condition, although any error of refraction should be corrected and the proper glasses worn constantly. It must be remembered that neither in this type of retinal affection nor in hyperesthesia of the retina are spectacles alone sufficient. A consideration of the etiological factors only will supply indications for the proper constitutional and local measures.
Thrombosis of the retinal veins has been observed as the result of syphilis and with heart disease. Thrombosis of the central vein is sometimes seen with hemorrhagic retinitis, of which it may be the cause, and also in a few other conditions in which the walls of the veins have undergone some degeneration.
. As these lesions can be seen ophthalmoscopically, it is natural to expect with them certain symptoms more or less well marked. These are a scotoma of varying size, corresponding in extent and location to the part affected by the thrombus, and usually floating bodies in the vitreous (hyalitis), causing musce volitantes. Complete thrombosis of the central vessel causes great engorgement of the veins, interrupted venous circulation, strong venous pulse, streaked disk margins, and numerous retinal hemorrhages.
The diagnosis is comparatively simple when the vitreous is sufficiently clear to enable the lesions to be recognized by the ophthalmoscope.
No local treatment is of any value, but potassium iodid, mercuric chlorid and other alteratives may be given to encourage absorption of the effused blood.
Telangiectasia of the retinal vessels, aneurysm of the central artery, and varicose veins of the retina, have also been observed, but they are so rare as to deserve only mention here. They show, in general, that while we have in hyperemia the first step toward a real inflammation, the vessels of the retina also undergo the same variations from the normal standard as occur in other parts of the body.
Retinitis. Under this general term are included the various types of inflammation of the retina.
Forms of Retinitis. These are not always properly described by the names given to them, nor is the term itself always exactly applied. Thus, it sometimes expresses a pathological condition for instance, serous, parenchymatous, or suppurative retinitis; or it is used to denote the results or accompaniments of such inflammations for example, hemorrhagic retinitis; or, again, it is employed to describe the cause e. g. syphilitic or albuminuric retinitis. Again, retinitis pigmentosa and other names indicating inflammation are given to retinal lesions which are not inflammations at all, in the true sense of the word. Therefore, it is desirable to keep in mind the three types of inflammation to which the retina is subject namely, the serous, the parenchymatous, and the purulent.
These types, more or less modified, are met with in conjunction with certain systemic conditions : thus the serous type is often found with syphilis, while the parenchymatous type occurs principally with changes in the kidneys. The different retinal inflammations can best be understood, therefore, by considering these types first, and later their modifications, after which another group the scleroses of which the so called retinitis pigmentosa is a type, will be described. That is, all forms of retinitis may be arranged into four groups:
I. Simple or Serous Retinitis. Allied to this are (a) Syphilitic retinitis; (b) Sympathetic retinitis; (c) Retinitis from concussion.
II. Parenchymatous Retinitis. In this are included(a) Albuminuric retinitis; (b) Diabetic retinitis; (c) Leukemic retinitis; (d) Syphilitic chorio retinitis; (e) Hemorrhagic retinitis; Macular retinitis. a. Retinitis albescens Retinitis circinata Solar retinitis; 0 Symmetrical changes at the macula lutea.
111. Embolic or Septic Retinitis.
IV. Retinal Sclerosis. (a) Retinitis pigmentosa, typical form; (b) Retinitis pigmentosa, atypical form (c) Retinitis proliferans.
Serous Retinitis (Retinitis Simplex; Edema of the Retina; Peripapillary Retinitis). Retinal inflammation of slight degree, marked only by hyperemia and exudation, is known as simple retinitis. When, however, there is besides an alteration of the deeper tissues (hyperplasia), the term parenchymatous is used. It is evident that the two forms may merge into each other by imperceptible gradations under certain circumstances, and that a process which begins as simple retinitis may pass into the parenchymatous form. Practically, however, the first type or stage retains its own characteristics so constantly that it may be properly considered a distinct disease.
Varieties. As the retinitis may vary according to the depth to which the lavers are invaded, it may also vary in the extent superficially or in the secondary changes accompanying it. When the edema is limited to that region where the retina is the thickest namely, about the edges of the optic nerve the appearance presented is so peculiar as to warrant the name peripapillary retinitis.
Diffuse retinitis is more common. The edema, extending over the entire retina, veils to a greater or less extent the features of the fundus.
Etiology. The causes to which simple retinitis has been ascribed are manifold. Among these have been enumerated excessive use of the eyes under unfavorable conditions, refractive error, dazzling light, exposure to cold, chill, etc. In many cases, however, it is due to syphilis. It may be the initial change of other forms of retinitis presently to be described.
Pathology. The term inflammation ordinarily is applied to nutritive disturbances accompanied by redness, swelling, heat, and pain; but it is necessary to modify this definition in accordance with the alterations to which this pathological process is subjected by the different structures of the body in which it occurs. Especially is this the case in retinitis. In the early stages of the inflammation a hyperemia, more or less well defined, is present. This corresponds to the redness which accompanies an inflammation elsewhere. As a result of the distention of the vessels there is naturally edema, with some infiltration of the leukocytes into the inner layers of the retina, particularly into the nerve fiber and ganglionic layers, or even into the vitreous humor. Similar lesions would produce swelling if they occurred in other portions of the body. These two pathological changes constitute practically all which are present in pure, simple retinitis.
Objective Signs. The ophthalmoscopic changes are as slight, proportionately, as are the pathological alterations. They are
(1) Edema of the retina. The features of the retina can usually be distinguished, but they appear as if seen through a mist. The retina often has a somewhat grayish aspect; almost invariably the vitreous is more or less
Clouded by the infiltration, and the details of the retina are consequently indistinct.
(2) The vessels, especially the veins, are altered. They are more tortuous and have a greater number of branches than usual. They are distended at some points or disappear under the swollen retina at others. Sometimes the arteries appear reduced in size from compression.
(3) Hemorrhages are occasionally met with, but are not common with the serous variety of inflammation; nor, indeed, are any other of the more extensive alterations present which are found when the deeper layers of the retina are affected.
Subjective Symptoms (l) The first and most important symptom is a diminution in the acuity of central vision, often associated with greater or less contraction of the field. Occasionally, in the circumscribed variety of retinitis, only one spot is involved, perhaps near the equator, and then not only is it easily recognized because of the contrast which this area presents to the surrounding tissue, but an exact examination of the field shows a welldefined scotoma corresponding to the affected part.
(2) Distortion of vision due to the altered retina. The exudation into the retina changes the position of that membrane more or less, and, together with the unequal pressure upon the rods and cones, produces peculiar distortions of the retinal image. Thus, objects may appear larger than normal (megalopsia), or the patient may describe them as being distinctly smaller (Micronesia), or, finally, they may be distorted in various ways (Loring). When the difficulty exists in both eyes it is not always easy to decide what the peculiarities are in each, unless one eye be covered or diplopia is produced with a prism.
(3) A symptom occasionally present in this type of retinitis is the ability to see better by imperfect illumination for example, in the evening than where the light is bright. This condition has been called by Arlt nyctalopic retinitis. Evidently, however, it is only a symptom.
(4) As there are no sensitive nerve fibers in the retina, often a high degree of inflammation passes without pain, imperfect and distorted vision being about the only symptoms which attract the attention of the patient.
Diagnosis. This is easily made, especially in cases not far advanced) there being then no danger of confusing the serous with the parenchymatous form. The veiling of the fundus when the inflammation is diffuse, or the grayish patches when it is circumscribed together with the changes in the vessels, or swelling of the retina, with the corresponding diminution of vision, furnish a characteristic picture.
Prognosis. This is uncertain and depends somewhat upon the cause. It can never be safely foretold that a serous inflammation thus begun will not assume the parenchymatous form. When the inflammation is not present in a marked degree, or when it has existed for a comparatively short time, absorption is apt to take place; or when the serous inflammation is dependent upon syphilis the prognosis is more encouraging, inasmuch as this variety frequently yields readily to treatment.
Treatment. Whenever the cause can be determined, it is of course necessary to combat that first. Where there is a distinct history of syphilis, or when the serous retinitis is apparently connected with any systemic disturbances, the plan to be pursued is plain enough; but, unfortunately, the causes are by no means always clear, and in those cases only local treatment remains. Usually much attention is given to protecting the eyes from bright light, colored glasses or even a dark room or a bandage being advised; but in this disease, as in' others requiring confinement in a dark room, the patient should be given a certain amount of exercise daily in the open air. The artificial leech, cold applications, and, in general, an antiphlogistic form of treatment are advisable in inflammations of the sthenic type'. Mydriatics are not usually mentioned in this connection, but it is undoubtedly the case that atropin often assists in keeping the eye entirely at rest, and, although the dilated pupil allows more light to enter the globe, the improvement following the use of atropin is too common to warrant its omission.
Syphilitic Retinitis (Specific Retinitis). It is a question whether an inflammation of the retina occurs primarily as a result of syphilitic infection. Desmarres, among the French, and the English practitioners generally, are inclined to regard syphilis as commencing always in the choroid, and affecting the retina only secondarily. However this may be, a serous inflammation of the retina often results from syphilis.
In the pathological anatomy of this disease there is nothing sufficiently characteristic to distinguish it from serous retinitis due to other causes. Still, one peculiarity may be remarked viz. a tendency of the inflammation to be circumscribed instead of general. For this reason it is also known as retinitis with exudative spots (Galezowski), but these may exist at the same time with considerable general edema of the retina.
Symptoms. The ophthalmoscopic picture is such as has been described under Serous Retinitis, varied only by the local edema which are common in addition to the diffuse exudation. This, as before stated, obscures the whole fundus more or less, rendering indistinct the outline of the disk and the course of the arteries and veins, which are veiled by lines of grayish opacity. The papilla is discolored, and has been compared to a yellowish red oval seen through a covering of fog (Plate 5, Fig. 1.).
The subjective symptoms are also the same as those of simple retinitis. The “mist" before the eyes thickens slowly, and usually steadily. While there is no decided pain in the eyes, photophobia is sometimes present, and photopsies and scintillations are common. Indeed, some authors consider the last named symptoms as regular accompaniments of the serous form of syphilitic retinitis. Irregular and concentric contraction of the visual field, as well as various forms of scotoma, is commonly to be observed.
Date of Occurrence. Diffuse syphilitic retinitis may occur in congenital and acquired syphilis. In the acquired form of the disease it appears from one to two years after infection, sometimes as early as the sixth mouth, and, according to Alexander, is found in about 8 per cent. of the patients. One eye alone may be affected, but usually the second eye is also involved. Diagnosis. There is no appearance or symptom diagnostic of syphilitic retinitis. The tendency to develop circumscribed spots of edema, in addition to the diffuse exudation, may perhaps point to syphilis, but a history of the case giving conclusive evidence of the general infection is the only testimony on which reliance can be placed.
Prognosis. This is much more favorable than in cases of retinitis arising from other sources.
Treatment is of course governed by the cause; for, although the same precautions are to be taken locally as in serous retinitis, much depends upon the antisyphilitic remedies. Hirschberg insists that it is not safe to rely on potassium iodide, and that mercurials should always be given, for they probably have a beneficial effect upon such forms of inflammations in addition to their specific action. The use of tonics is also desirable, and every effort should be made to improve the general condition of the patient.
Central relapsing retinitis, a rare form of syphilitic retinitis, appearing in the form of gray or yellow areas in the macula, or as numerous yellowish white spots and pigment dots, or as a diffuse opacity of this region, is a late manifestation of syphilis. Relapses are frequent.
Sympathetic Retinitis. Before leaving this group of retinal inflammations mention should be made of that form which accompanies sympathetic iridocyclitis (Graefe). While the ophthalmoscopic appearances and symptoms of this variety are virtually the same as in other forms of serous retinitis, this is specially important as being sometimes one of the early manifestations of approaching sympathetic ophthalmitis. Its recognition furnishes indications as to the advisability of removing the eye first affected, should that question arise (see also page 348).
Concussion of the Retina (Commotio Retina Edema of the Retina). This condition may follow injuries of almost any variety, but especially a blow on the eye from a cork, rubber ball, or other similar substance. It is characterized by slight retinal changes and more or less loss of vision.
The pathology of this condition has not been satisfactorily settled, for in some cases blindness results when the ophthalmoscope shows an almost normal retina, and in others very marked variations from the standard of health seem compatible with good vision. Whatever other effects ma y be produced by the injury, it is certain that after the blow which is not neces¬sarily directly on the eye there often appear small points of edematous exudation in the retina, or these may coalesce, and the typical cloudy exudation seen in serous retinitis may cover a considerable area of the fundus.
Corresponding to this or extending beyond it is a scotoma, more or less well marked. Such an exudation can be seen best a day or two after the injury, but ordinarily it soon begins to absorb, and, though it may disappear entirely, the blindness, partial or total, may persist. Decided retinochoroiditis, the result of concussion, may occur. These cases are often of interest from a medico legal point of view, and when malingering is suspected the tests for detecting that must be made with unusual care. An important complication in these cases is the development of transitory astigmatism.
The treatment locally is similar to that for edema of the retina. Stress is laid on the good effect of long continued Mydriasis (see also page 364).
Parenchymatous Retinitis (Retinitis Perivascularis). In the serous type of retinal inflammation, as already stated, hyperemia and edema are present, but little or no further structural change. When, however, there is hyperplasia, and when the deeper parts of the membrane become affected, the condition is generally called parenchymatous inflammation. It will be seen at once that in some respects this is like the type just mentioned, except that this process is more advanced.
Etiology. The causes are sometimes easily traced, especially when dependent upon albuminuria, intracranial disorders, or certain general diseases, but at other times they are difficult to determine.
Pathology. The same changes occur as in the serous variety namely, hyperemia with edema, but the latter is frequently wanting, and there develops instead an infiltration of cells or metamorphosis of the connective tissue. This infiltration takes place, by preference, in the inner granular or in the intergranular laver (Arlt). At the same time alterations occur in the walls of the capillaries. It has not yet been clearly established which is cause and which effect is; and from the fact that the walls of the vessels so often undergo degeneration, this form of retinitis has also been called retinitis perivascularis (Iwanoff).
these early stages there results (1) an entire absorption of the inflammatory process; or (2) partial absorption with partial destruction (namely, partial atrophy of the retina); or (3) a total atrophy i. e. the retinal elements pass into a form of cicatricial tissue, and other alterations go on in the nerve tissues.
Appearances. The vitreous being free from exudations, and edema usually being absent, the features of the fundus are distinct. The increased amount of blood causes the arteries to appear full, often tortuous, and the terminal branches extended while the optic nerves take on a reddish hue. The veins give similar evidence of the hyperemia, and occasionally, as an accompaniment of such a distention of both arteries and veins, extravasations into adjacent tissues occur.
This is especially true in certain forms of retinitis of nephritic origin. In these cases the hemorrhages extend into neighboring parts of the retina as small reddish points. Where the vessel gives way through a considerable portion of its extent there results a linear extravasation. This form has been described as a separate kind of retinitis, called hemorrhagic retinitis. In fact, there is an endless variety in the position, form, and extent of these hemorrhages, so common in some types of retinitis.
Subjective Symptoms. These are similar to those described in connection with serous retinitis. The same diminution of vision is always present, but in a much more marked degree. When the parenchymatous inflammation is general there may be total blindness, or, if it is circumscribed, there is a well marked scotoma in the corresponding portion of the field.
Distortion of objects or similar visual disturbance is unusual, the retinal changes being too deep and extensive, but photopsies and scintillations are not uncommon. With this form of retinitis also there is no pain. Indeed, the advance of the disease is so entirely free from this symptom that when the inflammation affects only one eye the patient sometimes discovers the blindness by chance, or often not until the same process in the other eye makes him aware of his condition.
Diagnosis. A distinction between this and the serous form of retinitis is not difficult in typical cases, but there are intermediate stages in which it is unwise to decide with certainty. Indeed, it is possible to see the serous and parenchymatous type of inflammation present in the same retina at the same time.
Prognosis. This is grave. Absorption does occur, and in certain instances normal vision returns, but this is very rare, except in the retinitis of pregnancy. In the large majority of cases the cell infiltration is followed by connective tissue changes, with subsequent atrophy, the vessels appearing later as whitish threads.
Treatment. Locally this is the same as that already advised for serous retinitis. The general treatment depends on the systemic condition which is producing the disease.
Nephritic retinitis is a generic term including retinitis albuminurica and certain other forms of retinal changes accompanying diseases of the kidneys. These have been grouped under a single term, because they are the result of disease of the kidney, because the ophthalmoscopic appearances are similar and the pathological anatomy is in some respects identical. Diabetic retinitis is sometimes described under the same generic term, but inappropriately, as it is not the result of renal disease. For a clearer understanding of the subject it is better to consider each of these varieties in order.
Albunlinuric Retinitis (Retinitis Gravidarum; Renal Retinitis; Retinitis of Bright's Disease). This form of retinitis is characterized by imperfect vision, by definite ophthalmoscopic changes among which those in the region of the macula are most noticeable and by certain alterations in the structure of the membrane.
Etiology. Even before Helmholtz gave us the ophthalmoscope, Bright, Landouzy, and others bad called attention to the frequency with which socalled amaurosis accompanied albuminuria. It remained for later observers, however, to determine more exactly the dependence of one upon the other a relationship which has been frequently and carefully studied.
If this disease ' is the result of albuminuria, the question naturally arises, Why do so few albuminuric patients complain of imperfect vision? The failure of vision usually escapes observation, because there is seldom or never any pain in the eyes, and, as the macula itself is often the last to be affected, the actual condition of the retina is neglected, attention being directed to other symptoms. But ophthalmoscopic examination of a large number of albuminuric patients, whether complaining of imperfect vision or not, indi¬cates that the retina is affected in as many as one fifth (Lecorche) or one¬ third of them (Galezowski). Indeed, it may happen, exceptionally, that the retinitis shows itself in a typical form before it is possible to detect albumin in the urine (Dixon, Abadic), as was illustrated also by a case reported by the writer.
Although chronic granular kidney is the usual cause of albuminuric retinitis, it also occurs with large white kidney and lardaceous disease. But attention should be directed specially to the albuminuria of pregnancy as a very frequent and important etiological factor. The relation between the two is as uncertain in this variety of the disease as in the former, but without doubt a considerable proportion of pregnant women who have albuminuria suffer also from the form of retinitis under consideration. Moreover, it is well known that patients afflicted in this way during one gestation are apt to have a recurrence of the same symptoms when pregnant again. The fact that the retinitis may result in partial or total loss of vision, which can last permanently, even though the cause be temporary, indicates the importance of this phase of the subject. It will be referred to again when the question of treatment is considered.
Symptoms and Pathology. The pathology can be studied to best advantage by first noting the symptoms and the ophthalmoscopic changes upon which these depend. It should be remembered, however, that the process is essentially a parenchymatous inflammation. The increased vascularity to be described later tends to result in hemorrhages, and while edema is slight and the vitreous clear, there is hyperplasia in the deeper layers or fatty degeneration of cells into those portions. Even a sclerosis of the nerve fibers may also occur in spots (Muller).
The only local symptom of which the patient complains is imperfect vision. Sometimes this begins gradually and increases slowly; sometimes the onset is sudden and the advance rapid. The amount of inconvenience does not correspond necessarily to the extent of the retinitis, but rather to the degree in which the macula lutea is involved. Sometimes only the macula itself remains intact, and the patients are surprised to find that, although the central vision is practically normal, they are otherwise blind. The impairment of vision, like the retinal changes, is usually about the same in each eye; but unilateral albuminuric retinitis is not a rarity. The lesions may, exceptionally, remain monolateral till death. More commonly a monolateral case is converted after a time into the ordinary bilateral variety.
The ophthalmoscopic appearances of retinitis albuminurica are
(1) Fatty deposits, more or less numerous, in the posterior segment of the retina. These white or yellowish white plaques are usually well defined, although the edges shade off gradually into the natural color of the retina. They may be limited to the vicinity of the macula from which they radiate, or may cover most. of the posterior pole of the eye, according to the extent to which the retina is involved. Sometimes these spots of exudation are exceedingly small, with edges so sharply defined as to look like minute white dots. In 'nearly every case of retinitis albuminurica a group of these dots can be seen more or less completely surrounding the macula. In that vicinity their arrangement and form are so characteristic as to present a picture quite diagnostic of this disease. In the macula itself there is often a white spot, and almost invariably radiating from that point are numerous thin dashes of nearly glistening white which stream of in different directions, this appearance being due to the arrangement of retinal fibers (Schweigger). The lesion is sufficiently peculiar to be easily recognized when once seen (Plate 5, Fig. 11.). If the average physician appreciated bow readily this picture of retinitis could be detected, it is probable that the ophthalmoscope would be used much more frequently. Such spots about the macula may persist long after every other trace of the disease has subsided. This is especially the case in the albuminuric retinitis of pregnancy.
(2) The retinal hemorrhages which accompany albuminuric retinitis are peculiar. They are linear and flame shaped, and they extend along the arteries, which are perhaps obliterated in parts, the extravasations being due primarily to changes in the walls of the vessels. Round, dotted, and sheet like hemorrhages may also occur.
(3) Next to the alterations in the retina itself, those which involve the optic nerve should be mentioned. As would naturally be inferred, the edges of the nerve become indistinct; it is often swollen, pushed into the vitreous, apparently, or streaked with diverging vessels; in a word, it presents the picture of neuritis or papillitis.
The foregoing is a description of a typical case, though of course each stage of its development can seldom be seen. Many variations occur. The disease may be characterized by small white spots, associated with comparatively inconspicuous hemorrhages in the fiber layer the so called degenerative type; or it may manifest itself as a violent neuro retinitis, with extensive hemorrhagic extravasations the so called in inflammatory type. Sometimes comparatively small dots in the macula and single small hemorrhages may be the signs of renal retinitis.
Diagnosis. This is not difficult in typical cases. To recapitulate, the chief signs are (I) Imperfect vision in both eyes, either central, or with contracted field, or with scotoma. (2) Fatty deposits in the retina, especially in the vicinity of the macula. (3) Retinal hemorrhages, striated in form.
(4) Secondary neuritis.
Prognosis. This depends upon the variety and extent of the lesion in the kidney. It is comparatively good when the amount of albumin is slight or variable, as occurs in the milder forms of typical Bright's disease or frequently in the last states of pregnancy.' The question becomes more serious, however, when the renal changes are extensive. Then the retina becomes more and more involved as the kidneys become disorganized, and the slowly but steadily increasing darkness foretells the fatal end. While the albuminuric retinitis of pregnancy usually ends vith gestation or soon after, the prognosis in certain instances is grave in the extreme, for with vision greatly impaired, or perhaps lost, the patient may still live on for years.
Treatment. Locally, there is little or nothing to be done. It is well to protect the eyes from bright light by means of colored glasses, and to abstain from prolonged efforts at accommodation, but with these instructions to the patient the therapy of the ophthalmologist ends. After that he may watch with interest the progress of the retinitis ; be may prescribe iron, alone or with bichlorid of mercury, advise steam baths, etc. ; but the important part of the treatment belongs rather to the province of the physician or, in certain cases, to the obstetrician.
When this retinitis occurs in a pregnant woman another and very important question arises: that is, whether premature labor or even abortion may riot be induced if by that means it is probable that the vision, and perhaps the life, of the patient can be saved. In the space here available it is impossible to give even the principal arguments for or against such a procedure. Suffice it to say that, in certain rare instances this procedure is permissible when the complaint or relapse appears in the earlier months, or when the history of former pregnancies shows a tendency to severe attacks of albuminuric retinitis.
Diabetic Retinitis. Another variety of retinitis is that known as retinitis diabetica or glycosuric retinitis. In the typical form it occurs, as a rule, only with diabetes Satellites, but it has also been known to be caused by diabetes insipidus Bowman Bader, Hansell). It occurs late in the disease, when other serious complications may be present e. g. gangrene.
Pathology. This is not well understood. As the vessels are probably affected primarily in all these forms of retinitis by a form of perivasculitis, this produces, directly or indirectly, most of the changes in the retina which characterize the disease. The pathological anatomy, as shown by the few sections thus far made, does not differ greatly from that of albuminurie retinitis. There are similar deposits of fatty degeneration, similarly situated with respect to the layers of the retina, bui they are in general small, the edges are well marked, and especially is it to be noted that they are Dot grouped about the macula in the manner so distinctive of albuminuric retinitis. As for hemorrhages, these are small, if existing at all.'
The secondary neuritis is either lacking or atrophy begins very early, the latter condition being apparently a feature of the pathological picture.
Symptoms. These are similar to those of albuminuric retinitis viz. imperfect central vision with contraction of the field and the ophthalmoscopic appearances also resemble those of the latter disease very greatly; indeed, they are in many respects identical, except that the hemorrhages are less in size, and, as before remarked, there are few or Done of the peculiar white radiating spots about the macula.
Diagnosis and Prognosis. The appearances above mentioned may be sufficient to render it possible to separate this from other varieties of nephritic retinitis, irrespective of tests for sugar. The prognosi's is grave.
Treatment. As diabetes is counted among diseases difficult to treat suecessfully, reliance must be placed on proper diet. Nothing can be accomplished by local treatment. The general precautions mentioned under serous or parenchymatous retinitis should be observed.
Leukemic retinitis belongs to this group of inflammations, and is almost exclusively caused by splenic leukocythemia. Both eyes are affected. Leukocytes not only invade every portion of the retinal tissue, but opaque deposits, sometimes fringed with a reddish border, are seen extending from the macula to the equator. These have been found by Leber to consist almost entirely of lymph corpuscles..
The color of the vessels in the retina is also peculiars The arteries are small, pink, or even yellowish, the veins large, broad, and rose red, and the retinal tissue pale yellow. Considerable swelling of the papilla is usually present, and occasionally spots develop near the macula similar to those found in albuminuric retinitis. The symptoms are those of parenchymatous retinitis.
Diagnosis is usually easy; exceptionally, however, there is difficulty in distinguishing this disease from albuminuric retinitis, but a count of the blood corpuscles of course determines the cause. In place of the typical appearances there may be a diffuse opacity of the retina.
There is no treatment except to protect the eyes and improve the general condition, if possible.
Syphilitic Chorio retinitis. Svpbilis, as before stated, tends to show itself first in the uvea, and the retina is probably affected later; or else inflammation develops simultaneously in the retina and choroid. Indeed, sometimes in the same person a serous retinitis may be found in one eye and a chorio retinitis in the other, or the two diseases may exist in the same eye. It occurs from six months to two years after primary infection.
The pathological anatomy combines the features of perhaps the serous, or always of the parenchymatous retinitis, or of both, with those of a Choroiditis.
Symptoms. In pure chorio retinitis of certain types the vitreous is clear, and the usual absence of marked edema renders the details of the retina distinct. In this class of cases retinal hyperemia, and often hemorrhages, are found, or a neuro retinitis. But the most characteristic appearances are spots Of exudation of various size and irregularly distributed. When these first appear they may be like spots of edema whitish or elevated ; later more or less complete atrophy of the retina takes place, and there results a dark or black area showing the choroid with corresponding distinctness. These spots, when small, are similar to those seen in retinitis pigmentosa. If the choroid also undergoes atrophy, white spots (the sclerotic), fringed with the black cells of the choroid, are visible. Should an artery or vein happen to cross such a spot, the vessel can be easily distinguished in the early stage, but later its outlines become indistinct ; it is cut off, and atrophies there with the surrounding tissue (Plate 5, Fig. 111.).
In other varieties of syphilitic chorio retinitis in the early stages there is diffuse punctate opacity (hyalitis punctata) of the vitreous, especially in its posterior layers, and marked edema of the peripapillary retinal layer. Occasionally the iris and posterior layers of the cornea participate in the inflammation. Later the ophthalmoscopic changes are similar to those described in the preceding paragraph (see also page 353).
The subjective symptoms are analogous to those of other types of retinitis lessening of central vision, contraction of the visual field, scotomas, diminished light sense, and sometimes night blindness. Pbotopsies, micropsia, and megalopsia are present.
Treatment. This consists in the use of mercurials internally or by inunction, and the administration of potassium iodid. The eyes should be protected, and occasionally the artificial leech is advisable.
Hemorrhagic Retinitis is often described as a separate disease, but really it is only a form occasionally assumed by inflammations of the serous type, but most frequently by those of the parenchymatous type. For the latter reason it is mentioned in this connection. Again, variously shaped hemorrhages may appear in the retina and occasion sufficient irritation in surrounding fibers to create a retinitis.
Etiology. The hemorrhages may be dependent upon syphilis, and in that case the walls of the vessels are altered (endarteritis, formation of thrombi), so that the hemorrhages, often small and fine, stream off, as it were, in irregular lines from the region of the nerve.
Most frequently, however, the hemorrhages are found with nephritic retinitis and with other types of retinitis dependent upon constitutional diseases. Then they are rather linear in form, but often large and irregularly distributed. Hemorrhagic retinitis may also accompany cardiac disease, general arterial sclerosis, suppressed menstruation, and the climacteric.
Hemorrhages into the retina without Signs of retinitis (apoplexy of the retina) may be the result of senile changes in the walls of the vessels. Then the extravasations are apt to be large, irregular, and to appear even from the first, of a darker hue than that otherwise seen. The region of the macula is liable to be the seat of such extravasations as the arrangement of the fibers in this locality predisposes to them. When they occur there they produce an irregular blotch or oval, usually with the longer diameter vertical, and a corresponding central scotoma. Hemorrhages of large dimensions and drop like form usually mean an extravasation between the internal limiting membrane of the retina and the hyaloid membrane of the vitreous. Recent investigations by J. Herbert Fisher indicate that the blood is poured out from a retinal vessel probably a minute artery and detaches the internal limiting membrane from the retinal layers, accumulating in the space thus formed. These are the so called subhyaloid hemorrhages, which occur at the yellow spot more than at other parts of the fundus (Plate 5, Fig. IV.).
Although many of the causes of retinal hemorrhage have been enumerated, a summary based upon Dimmer's classification may be added:
(a) Hemorrhages caused by changes in the composition of the blood and the tissues of the blood vessel walls : Pvemia, septicemia, ulcerating endocarditis. diseases of the liver, spleen, kidney, and atheroma of the vessels; loss of blood (menorrhagia, hematemesis), anemia (simple and pernicious), hemophilia, purpura, and scurvy; diabetes and gout; malaria and recurrent fever.
(b) Hemorrhages caused by disturbances in the circulation : Hypertrophy of the heart and stenosis of the valves; thrombosis of the central vein of the retina and embolism of the central artery; suffocation, compression of the carotid, hemorrhages in the newly born ; and menstrual disturbances.
(c) Hemorrhages caused by sudden reduction of the intraocular tension e.g. after iridectomy in glaucoma and by traumatism: Among the latter may be classed retinal hemorrhages after large cutaneous burns.
Pathology. A perivasculitis or fatty degeneration of the walls of the retinal vessel, produced by the general or local disturbance, permits rupture of the artery or vein and consequent extravasation. Sometimes the hemorrhage is caused by diapedesis of blood corpuscles. In some cases the hemorrhages are. superficial, and leave the retina healthy, but in other instances atrophy results and a scotoma permanently marks the spot. Hemorrhages may take place in any layer of the retina, and by preference follow the larger blood vessels. Sometimes they burst through the limiting membrane and pass into the vitreous. The macula, as before stated, is a favorite spot for these lesions. With the hemorrhages may be the pathological changes incident to the various types of serous and parenchymatous retinitis.
Prognosis. At times, as already noted, superficial retinal hemorrhages are absorbed without leaving permanent scars; but if the macula is attacked, the visual disturbance is apt to be severe and lasting. Not only in this sense IS the prognosis unfavorable, but the retinal hemorrhage, in most instances a sign of serious constitutional disturbance, may be the forerunner of extravasations in vital centers. Secondary changes in the optic nerve may result; sometimes glaucoma is a consequence (see page 384).
Treatment. This should be directed toward removing the cause whenever possible to determine it. Internally, if not otherwise contraindicated, iodid of potassium may be given, ergot, small doses of pilocarpin, and bichlorid of mercury, 'according to various indications.
Macular retinitis is a term which, though often used for only one form of retinal inflammation occurring in the macula lutea, is really more general in its application, and may include several types of inflammatory retinal change specially located in this region. The details of these alterations are not yet clearly understood, and consequently they cannot be separated from each other, neither by their ophthalmoscopic features nor by what we know thus far of their pathology; for it will be remembered that the appearances of the macula lutea vary considerably within normal limits.
Mention has already been made of the so called 11 Gunn's dots," and these are ordinarily considered as non pathological variations of the macula, for the reason that normal vision is found when they exist. Very nearly allied to them we have Retinitis Punctata Albescens (Central Punctate Retinitis). This affection is classed as a pathological condition, Dot so much because it differs materially in appearance from the Gunn's dots, but because central vision is more or less impaired. Fuchs and Liebrecht call attention to the similarity which this disease may bear to retinitis pigmentosa, in so far that it may occur in children, affecting several members of the same family, and, moreover, in children of blood relations. Occasionally there are night blindness and contraction of the visual field. Other cases have been reported in middle-aged patients with unchanged peripheral fields.
The most prominent feature is a group of fine, shining dots in the vicinity of the macula, often extending toward the optic nerve. Sometimes the dots are present in great numbers. A central scotoma, more or less marked, can be found, though often exact measurements are necessary to determine it ; the peripheral field is unaffected. Sometimes vitreous hemorrhages occur.
Nieden and Landesberg think the spots can be made to disappear by the administration of potassium iodid and mercury, but the real effect of any treatment is uncertain.
Retinitis circinata is a term recently used by Fuchs to describe an appearance of the macula somewhat similar to that found in albuminuric retinitis. A yellowish gray opacity is found in the macular region, surrounded at some distance by a zone of white spots or larger white patches. It is probable that this is not an inflammatory process, and that it is due to hemorrhages taking place in this locality. Some writers regard these points only as accompaniments of albuminuric retinitis (Spicer Holmes), but in a typical case recently described by Hartridge no albumin could be found.
Solar Retinitis. Since the sight purple in the retina was discovered by Boll, what before appeared a mysterious action of the light upon the retina is better understood. When an excessive amount of light enters the eye for a considerable time the sight purple is destroyed to such an extent that it is not renewed either promptly or entirely. These changes in the retina when slight are not visible with the ophthalmoscope. Their effect is shown by considerable loss of central vision, though this is not necessarily complete; and by more or less limitation of the visual fields.
When, however, the crystalline lens has focussed the rays from a strong light, with the accompanying heat, upon the retina as, for example, when an eye has been directed toward the sun the changes produced in the yellow spot are not only more lasting, but they can often be seen with the ophthalmoscope. This has occurred particularly during observations of an eclipse of the sun, or the effect of such strong light has been shown by experiments on animals. A distinct exudation in the form of small spots of retinochoroiditis can be seen in the vicinity of the macula, and, although these appearances gradually subside, a central scotoma may persist, which indicates that the alterations in the retina were extensive.
The pathological changes are not clearly understood, but they are probably more nearly allied to the parenchymatous type of inflammation than to any other.
No treatment has been found of value in even lessening the size of the scotoma, although the protection and rest of the eye are indicated.
Symmetrical Changes at the Macula Lutea in Infancy. This peculiar and rare condition was first described by Waren Tay, the clinical appearance being in every way similar to that which exists in cases of embolism of the central artery. The cherry red color of the macula, in the center of a grayish white Zone about the size of the papilla, is here, as in embolism, a very marked feature of the ophthalmoscopic picture.
The condition of the patient is always peculiar, the mental and physical condition being decidedly below the normal. It is not certain what gives rise to this appearance of the retina, although the changes are probably in the deeper layers, and examinations after death show a degeneration of the spinal cord and the pyramidal cells of the cortex. The disease is always fatal, death occurring in from one to two years. In most of the cases reported the children were of Hebrew parentage.'
Suppurative Retinitis (Purulent Retinitis; Embolic Retinitis). This usually occurs in connection with severe inflammation of the choroid, but in rare instances the process can be noticed beginning in the retina before the vitreous has become cloudy.
Etiology. It may be caused by injury (e. g. foreign body), but the typical forms are due to cerebro spinal meningitis or to septic or puerperal conditions. It is also known to exist with a gouty or rheumatic diathesis. In some cases it is not easy to understand bow infection occurs; but it is also beyond question that bacteria may be transported from other parts of the body into the circulation, and, finding lodgement in the retina, give rise to a purulent inflammation.
Symptoms. It may happen that imperfect vision first attracts the attention of the patient, but ordinarily the iris or choroid has previously become involved, giving rise to ciliarv injection, pain, etc., the decrease in the field of vision or in the more import ant central vision resulting from the general inflammation. The disease is often limited to one eye. An ophthalmoscopic examination shows changes in the retina only in the early stages. These are exudations and hemorrhages which usually extend into the vitreous, the latter soon becoming so turbid as to obscure the details of the fundus.
The diagnosis is easily made on account of the acute symptoms, or when these are absent the appearance of the fundus is sufficiently characteristic.
The prognosis is extremely unfavorable. After suppurative retinitis is well established cure is impossible. Occasionally the more acute symptoms will subside, but the retina is always left thickened, more or less detached, and shrinks finally into a band of connective tissue.
Treatment. This is similar to that employed for an iritis or an iridochoroiditis. It is antiphlogistic. Atropin is of undoubted benefit in solutions strong enough and used often enough to keep the pupil dilated. Protention of the eye from light gives comfort, and the use of cold applications is necessary. When it is possible to reduce the temperature of the globe, it is probable that the development of the microbes is either temporarily or permanently arrested. In making cold applications to the eye they should be used only for a few minutes at a time , and care should be taken that the cloth or gutta percha bag or coil is not kept on the globe long enough to become warm.
Attempts have been made recently to carry out the principles of antisepsis in the treatment of these suppurative conditions. We know that sublimate solutions may be injected under the conjunctiva with but little inconvenience, and efforts have been made to extend the same plan of treatment to inflammation of the choroid or retina. Thus far, the method has met with indifferent success, but it is probable that intraocular injections, in some form, will prove of value, and, theoretically, they give promise of a brilliant future (see also page 400).
RETINAL SCLEROSES.
Thus far, the forms of retinitis which are more or less of an inflammatory nature have been considered. In addition to these, however, there are pathological changes which take place in the retina, not associated with any of the cardinal signs of inflammation, but which can be recognized by the ophthalmoscope, and which are characterized by certain symptoms. They are usually described as forms of retinitis, although it is a question whether that term should be applied to them. It is therefore better to class them together as forms of retinal sclerosis. In this group we have retinitis pigmentosa of the typical variety and of the variety with little or Do pigment, and with these may also be classed the so called retinitis proliferans.
Pigmented Sclerosis of the Retina (Retinitis Pigmentosa; Pigmentary Degeneration of the Retina; Pigmented Retina and Choroiditis. The term retinitis pigmentosa, is usually applied to an affection characterized ,by deposits of pigment in the retina of more or less peculiar form and location, the appearance being accompanied by certain definite symptoms.
As this term is ordinarily used, without qualification, it probably includes two and perhaps three diseases. The study of a large number of these cases shows that the retinas vary much from each other, and also that, while there is a certain type of symptoms to be expected, these are by no means always constantly present. As for the pigment, this not only varies in form and in the abundance with which it is found, but in some cases, where the subjective symptoms are particularly well marked, the pigmentation is absent entirely. In defining retinitis pigmentosa, therefore, we must consider that this is simply the name of a group of pathological processes nearly allied to each other, the exact nature of which is still unknown.
Etiology. The etiology of the disease is also obscure. It was formerly considered that consanguinity was the most important element in its production, and the evidence undoubtedly shows that it is a factor in the causation of certain varieties. But it is probable that the importance of this has been overestimated, while that of hereditary syphilis and some other conditions has been overlooked. It is markedly hereditary. The affection has been found among deaf mutes, idiots, and epileptics. The disease is either congenital or begins in childhood.
Pathology. In considering the pathology of retinitis pigmentosa it is proper to describe the morbid process which goes on in a typical case, but it is equally necessary to remember that this process is liable to many variations. It consists, in general (I) Of a proliferation of the connective tissue cells which form part of the supporting structure of the retina; (2) a sclerosis in the walls of the vessels, and consequently a contraction of their diameters; (3) atrophy of the nerve elements, with the destruction of the rods and cones; (4) usually pigmentary degeneration, taking on certain shapes which will be referred to later.
Symptoms. The symptoms and the ophthalmoscopic appearances of retinitis pigmentosa are
- Night blindness. This symptom is the one which ordinarily first attracts attention to the disease, although it is seldom noticeable until the ophthalmoscope shows changes in the retina already well advanced.
- Diminution of the Central Vision. This is almost invariably present, although occasionally good visual acuity remains for a long time. Sometimes it is associated with a true myopia, but more frequently the myopia is only apparent; for the patient approaches close to objects in order to obtain as large a retinal image as possible.
- Contraction of the Visual Field. In typical cases this contraction is peculiar, because the concentric restriction occurs with almost perfect regularity (Fig. 258). The contraction may be extreme, only a small central area of the field remaining. It is, however, liable to many variations.
- Occasional Color blindness. Failure to recognize red and green is the usual variety of this defect.
Ophthalmoscopic examination reveals the pigment, especially along the lines of the vessels, and always more abundant in the periphery than near the center of the retina. The temporal side of the fundus is generally more affected than the nasal side. The pigment masses assume an appearance resembling bone corpuscles, and by the frequent union of their processes simulate the Haversian canals. This results in a picture so peculiar as to be easily recognized when once it has been seen (Fig. 259).
The papilla is usually yellowish gray in color, with only slight mixing of red, and, as Leber has noticed, it sometimes has a glistening, tendon like whiteness, such as is seen in extraocular atrophy. The lamina cribrosa is also more or less covered, and the whole papilla is, in general, smaller than is ordinarily the rule. The vessels are greatly contracted and their number is diminished. Often their walls contain white patches or are edged with white lines. The general fundus is frequently wainscotted on account of the absorption of the retinal pigmented epithelium. Posterior polar cataract may be a complication. Opacities in the vitreous are rare.
Diagnosis. This is usually easy. The symptom of myopia might lead one to suspect this defect of vision at first, but in the typical forms it is only necessary to examine the periphery of the retina, when the peculiar star like pigment dots which characterize the disease become apparent. The diagnosis is further confirmed by the presence of the other symptoms detailed, especially the night blindness. The disease is distinguished from disseminated choroiditis by the difference in the pigmentation. There is some resemblance between this affection and certain types of syphilitic retino choroiditis; but in the latter the pigment spots are not of characteristic form, they do not follow the blood vessels, and vitreous opacities are usually present. Pigmentary degeneration of the retina is always bilateral.
Prognosis. The disease invariably progresses from bad to worse. In certain cases it remains at an apparent standstill for many years, but gradually new spots appear, nearer and nearer the center of the retina and associated with a corresponding contraction in the field. The night blindness becomes more annoying, and by the time middle life is reached or old age approaches a large proportion of the sufferers cannot find their way about without assistance.
Treatment. Thus far, this has been equally unsuccessful in all forms. It is true that the subcutaneous injection of strychnine seems to retard the disease in some cases, and reports of the good effect of electricity, in the form of galvanism, have appeared, but, nevertheless, the treatment may be summed up by saying there is none thus far to be relied upon.
Non pigmented Sclerosis of the Retina (Retinitis Pigmentosa Atypical Pigmented Retinitis without Characteristic Pigment). This form has been referred to when considering the typical disease, and the differences between the varieties have been noticed. While it may occur in extreme cases, as before stated, that all the subjective symptoms of retinitis pigmentosa are present, with no pigment, so also are there various degrees between these two extremes in which the ophthalmoscopic picture agrees more or less completely with what might be expected from the symptoms.
The pathological process in these atypical forms is not difficult to understand. The disease apparently passes through three of the stages described when considering the usual form, but the last is omitted little or no pigmentary degeneration takes place. This is the only essential difference in the two forms, the clinical history, course, and prognosis being the same.'
Other atypical varieties have been described: massing of the pigment in the macular region and corresponding central scotoma; irregular distribution of the pigment, associated with clear, shining spots lying beneath the vessels ; and pigment degeneration accompanied with broad peripheral zones of choroidal atrophy. In rare instances the disease is complicated with chronic glaucoma.
Retinitis Proliferans. This disease, like retinitis pigmentosa, is not a true inflammation of the retina, but has been considered by Manz to represent a proliferation of the connective tissue of that membrane. Indeed, there is a proliferation of Muller's fibers and a formation of new connective tissue among them. It presents itself as feathery, bluish white expansions of tissue, often extending from the retina into the vitreous. These bands may occur in any portion of the fundus, and may follow the course of the vessels, but they are usually situated near the optic nerve, and bend about it in more or less concentric curves (Denig). New formed blood vessels occasionally lie above the masses. Vision is usually seriously disturbed.
The cause of the affection is not well known; syphilis and traumatism are etiological factors. Leber attributes the formation of these masses to repeated hemorrhages in the vitreous or retina. As a complicating circumstance there may be detachment of the retina. The ophthalmoscopic appearance is striking. In one case of retinitis albuminurica which the writer has observed these bands of connective tissue almost encircled the entrance of the nerve, and, curving thence toward the macula, presented a highly characteristic picture. As far as known, they continue unchanged in spite of all treatment.'
Angioid Streaks in the Retina (Retinal Pigment Strice). Pigment strie, the result of the metamorphosis of retinal hemorrhages, diffused, according to Ward Holden, in a linear manner through the deep layers of this membrane, present a striking ophthalmoscopic picture, resembling, in many respects, a system of obliterated vessels. Dark, reddish brown, somewhat granular bands or strie, lying beneath the retinal vessels, often in the neighborhood of the disk, extend over a considerable area of the fundus. Their direct connection with hemorrhages has been demonstrated by Plange, Knapp, Holden, and de Schweinitz; (Fig. 260).
Retinitis Striata. This name was proposed by Nagel to describe an affection originally pictured by Jaeger, and characterized by light or yellowishwhite stripes, often branched, lying beneath the retinal vessels. The stripes extend from the periphery toward the disk. They may be bordered by lines of pigment. The etiology of the stripes is unknown, but, like the angioid streaks, they probably have their origin in the metamorphosis of retinal hemorrhages (Holden). L. Caspar contends that all retinal striations or, as be calls the affection, chorio retinitis striata represent the final stages of spontaneously cured detachments of the retina.
Detachment or Separation of the Retina (Ablatio sive Amotio Retine). This consists in a separation of the choroid from the retina, causing the latter to float in the vitreous.
Etiology. The causes of detachment of the retina may be
- Stretching of the sclerotic and choroid. To this can be attributed the greatest number of cases. It occurs in high degrees of myopia (malignant myopia). The retina is attached only loosely to the choroid, and firmly about the optic nerve and near the ciliary processes. As the globe increases in size, the sclerotic and choroid, each being somewhat elastic, are stretched more and more, until the circumference of the retina becomes less than the space which it should fill, and there is, consequently, separation of the retina from the adjacent choroid throughout a part or the whole of its extent.
- The retina may be pushed from the choroid into the vitreous. This may be due to (a) a solid substance, as a tumor or cysticercus; or (b) a fluid, such as an exudation from the choroid. It is possible that a serous inflammation of the choroid is, in many cases, a cause of the retinal detachment. Hemorrhages in the choroid would, of course, produce the same result, this occurring, for example, in operations for glaucoma or as the result of injury.
- The retina may be drawn away from the choroid into the vitreous. Leber and Nordenson bold that the changes commence primarily in the vicinity of the ciliary body. A fibrillary degeneration of the vitreous commences and as that humor shrinks the retina is gradually drawn away from the choroid. Rupture of the retina occurs, and the fluid from the vitreous passes beneath it through the opening. Detachments of the retina of a similar kind may also occur when, from injury or operation, there has been any considerable loss of the vitreous humor.
Retinal detachment is more frequent in men than in women.
Symptoms and Pathology. The morbid conditions vary according to the causes above mentioned. Where the membrane has been pushed away and still rests on a solid base, as, for example, on a sarcoma of the choroid, it is immovable, still retains more or less of its normal color, and in parts may be found to be more vascular than usual. Ordinarily, however, there is fluid behind the retina, and it floats in a fluid vitreous. Then it has lost its usual color, and, although the vessels retain their place with regard to the retina, both may float together, moving with the motions of the globe. As the retinal vessels rise over the separated portion, they first lose the light streak, and finally appear as dark, tortuous cords, and are apparently smaller than normal. The border of the detachment is usually sharply marked from the normal fundus, and may be accentuated by a yellowish or even pigmented line. The fluid tends to gravitate toward the lower portion of the globe, and even if the detachment, which may be partial or complete, occurs originally at the side or above, the fluid finds its way between the retina and choroid, usually to the lower portion of the eye. Sometimes the detachments are quite small, like a series of furrows; at other times an almost circular separation occurs.
Important changes also take place in the tissue of the retina itself (Klebs). As the rods and cones are macerated by the fluid in which they float they become swollen, entirely losing their original structure and consequently their function. The bearing of these facts on attempts to replace the retina is evident.
The ophtalmoscopic picture of extensive retinal detachment is one which cannot be mistaken for anything else. With the upright image the observer sees the grayish white fold waving as the eye moves in various directions, and in the undulations the branches of the vessels are brought into view. The inverted image gives a general view of the condition, and often the whole or most of the detached area is brought into the field at once, showing still better the arrangement of the retinal vessels. They spread over the surface of the floating retina, sometimes appearing on the surface or again depressed beneath it, where it may be covered with a whitish cloud, probably due to local extravasation of the submariner fluid. The other portions of the retina are often almost normal, although the papilla may appear more congested than usual (Fig. 261).
Symptoms. (I) Imperfection of the Visual Field.When the detachment occurs suddenly for example, immediately following some strain or effort of the individual he notices what he calls a dark cloud or mist, which he may try to push away. This, of course, is the scotoma corresponding to the detachment. Wherever the detachment occurs there is corresponding loss of vision, and consequently the field assumes every possible variety of form (Fig. 262; see also Figs. 287 and 288).
2. Metamorphopsia. This is not of the slight degree found in serous retinitis, but is so great as to cause the lines of a page to be zigzag or the letters to be separated widely from each other.
3. Dyschromatopsia is also present, and the difficulty in recognizing colors is noted even in parts of the field apparently unaffected.
Scintillations or phosphenes cannot be produced by pressure on the eyeball over the separated retina.
Other alterations are not infrequent with detached retina opacities may, appear in the vitreous humor, and with these or independently of them iritis, irido choroiditis, or cataract.
Diagnosis. Extensive detachment, as before stated, is easily recognized, both because of the clearness of the ophthalmoscopic picture and from the subjective symptoms. If the vitreous is filled with opacities and obscures the details of the fundus, an examination of the visual field gives diagnostic proof. The difference between a retina separated by fluid or by a solid growth e. g. a tumor bas been pointed out.
Course and Prognosis. Usually the detachment extends more and more, and the portions of the retina which at first remained comparatively healthy either become detached or undergo pathological changes. In certain rare instances, however, the fluid is absorbed, and the retina is reapplied to the choroid with a corresponding improvement in the vision. It is not at all certain under what circumstances such an improvement occurs.
Treatment. Inasmuch as many of the cases of improvement have occurred when the patient was in a recumbent position for a considerable time because of illness or for other reasons, the plan of treatment usually advised first is rest in bed for days or even weeks. This is much easier to prescribe than to accomplish. Various other plans have therefore been suggested, which have for their object
(a) Absorption of the fluid by medication. This includes the administration of laxatives; meliorate of sodium, iodid of potassium, the hypodermic use of pilocarpin, mercurial inunctions, etc.
(b) Absorption of the fluid or coagulation by electrolysis. Attempts have been made by Wray and others to produce absorption of the subretinal fluid by means of the electric current. Clavelier recommends strength of five milliamperes continued one minute, and many excellent results have followed this method. More testimony is necessary, however, before definite opinions can be formed as to the relative value of this agent.
(c) Removal of the fluid by operation. Again, numerous attempts have been made to give exit to the subretinal fluid, with the hope that as the retina came in contact with the choroid it would be reapplied and resume its function. But whether that fluid was drawn away with a syringe or allowed to escape through a punctum in the sclerotic, the results have been for the most part unsatisfactory. Equally unreliable has been the plan suggested by de Wecker of passing a gold wire through the sclerotic and keeping up a constant drainage. Closely allied to this plan of treatment is that recommended long ago by von Graefe. In this method two needles are passed through the sclerotic, and, transfixing the retina as is done with the lens in laceration of the capsule, an opening is thus made in the detached membrane, the subretinal fluid being allowed to escape into the vitreous. Although this is one of the oldest methods, it still gives as good results as any other. Deutschmarm has recently recommended division of the retina and vitreous humor, all strands between the retina and the shrinking vitreous being thoroughly separated. He has also assisted his laceration operation by transplanting the vitreous humor of a rabbit into the affected eye. Finally, attempts have been made to set up an inflammation which by exudation should bring the separated membranes together. For this purpose iodin solution has been injected beneath the retina (Schoeler's method), but the reaction is so great that the plan is only mentioned to be condemned. Charles Stedman Bull's conclusion in regard to treatment is that no better means for dealing with retinal detachment has been devised than rest on the back in bed, atropin, a bandage, and the administration of some drug which may induce absorption of the subretinal fluid.
Glioma of the Retina. This growth is fully described in the section on Morbid Intraocular Growths, on page 494. Subretinal Cysticercus. This is occasionally met with, especially in Germany, but is practically unknown in America. When the entozoon is thus lodged beneath the retina, it develops there, pushes out into the vitreous, and the different stages of its growth can be easily studied with the assistance of the ophthalmoscope. These parasites have been removed with comparatively little injury to the eye or detriment to vision.
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