The optic nerve becomes paler and of a grayish-white appearance from a diminished amount of blood in its capillaries. The retinal vessels appear thin and contracted, the arteries can only be traced for a short distance into the retina while the veins present a contraction as they pass from the disc but become fuller again toward the periphery of the fundus. Minute haemorrhages in the vicinity of the macula or disc are sometimes found. There is a whitish opacity of the retina especially in the region of the macula and around the disc. This opacity may come on within a few hours or it may be delayed a week and after a time it begins to disappear. The opacity of the retina probably occurs in the inner layers, which receive their blood supply from the retinal arteries. In connection with the appearance of the around the macula there is seen a cherry red spot corresponding to the position of the fovea centralis. This bright red spot is due to the red color of the choroid shining through the thinned retina and is less likely to form when the stoppage is in some of the retinal branches. After some weeks the optic disc undergoes atrophy, the retinal opacity subsides the arteries show a white streak and may become converted into white threads; if haemorrhages have occurred they undergo degenerate changes.
The diagnosis depends upon sudden blindness in one eye, the ophthalmoscopic picture already described and the discovery of an endocarditis, valvular disease, or some other source of an embolus.
When the embolus becomes lodged in one of the branches it may sometimes be seen with the ophthalmoscope but as a rule the diagnosis is made on account of a swelling in the artery at some point with an obliteration of the vessel beyond. The visual disturbance is limited to a scotoma of the portion of the field involved.
Thrombosis of the vena centralis will present appearances very similar to those of an embolus of the artery, but with more inflammatory symptoms simulating to some extent retinitis haemorrhagica. In complete stoppage of the vein the optic disc will be nearly obliterated by haemorrhage, there will be numerous haemorrhages throughout the retina and especially along the course of the vessels and, together with these, yellowish patches of exudation. The veins will be enlarged and tortuous and the arteries small and straight and there may be a diffuse opacity of the retina. Thrombus usually occurs in old people with atheromata, and orbital cellulitis from erysipelas is frequently a cause.
In partial plugging of the vein there will be less opacity of the retina and fewer haemorrhages, the veins will be enlarged and the arteries contracted. Vision is wholly or partially destroyed and there may be recurrences of the haemorrhage. Interesting cases of thrombosis of the central vessels were reported by Loring which he had previously reported to the American Ophthalmological Society as cases of embolism. Later Angelucci gave the following differential diagnostic points.
“Embolism.- Normal course of vessels, arteries narrowed veins gradually increasing in calibre toward the periphery, no venous pulsation absence of retinal haemorrhages.
“Thrombosis.- Tortuousity of vessels arteries of normal calibre or nearly so, veins gorged with blood and here and there interrupted, venous pulsation and retinal haemorrhages.”
CAUSES.- Valvular disease of the heart especially when complicated by an acute endocarditis, is the most frequent causes of embolism. It occurs also in diseases of the kidney and in aneurisms. While a thrombus generally results from a phlebitis and also in cardiac diseases. Embolism may occur at any age usually affects but one eye.
PROGNOSIS.- This is always unfavorable, as embolism of the central artery, when complete, almost invariably leads to blindness. In some cases there will at first apparently be some improvement, but even in these cases optic nerve atrophy is apt to follow. When however a branch instead of the main trunk, is involved, the prognosis is of course more favorable.
TREATMENT.- But little if anything of value can be done for this condition. Operations to reduce the intra-ocular tensions, hopes of restoring the circulation, such as sclerotomy and paracentesis, have been practiced. Inhalations of the NItrite of Amyl have been credited with curing some cases of embolism.
Vision may in exceptional cases return without any treatment though it is better to give those remedies which seem to be constitutionally required.
By reference to Opium a case will be found described in which a cure was effected. Whether or not this was due to the opium administered is a question.
Hyperaesthesia Retina to light may be a symptom of inflammation, but it also results from close application of the eyes at fine work. It may also be found in neurotic or hysterical subjects and may or may not be associated with refractive errors.
SYMPTOMS.- There is a dread of light which may be so intense that the subjects will shield their eyes from all light and it often results in a blepharospasm. There is frequently lachrymation and more or less neuralgic pains around the eyes and head. The vision is not a t all affected but we find many of the asthenopic symptoms so often present in refractive errors, such a s fatigue upon using the eyes, with some blurring of near objects. Upon ophthalmoscopic examination we may find slight congestion of the disc and retina. In the higher degrees of irritation the outlines of the disc become ill-defined. Loring believes that atrophy of the optic nerve maybe excited by a chronic condition of irritation.
TREATMENT.- If dependent upon any anomaly of refraction the proper glass must first be prescribed.
In rare, severe cases it may be necessary to confine the patient in complete darkness for a week or more and then gradually accustom him to the light. Though usually it is better to advise exercise in the open air, having the eyes protected by smoked or blue glasses, or a shade. special attention must be paid to the general health of the patient.
Belladonna.- Hyperaesthesia of the retina particularly if dependent upon some anomaly of refraction or reflex irritation. Eyes very sensitive to light; cannot bear it, as it produces severe aching and pain in the eye and even headache. Flashes of light and sparks observed before the vision. The eye symptoms as well as the headache are usually aggravated in the afternoon and evening.
Conium.- Over-sensitiveness of the retina to light especially if accompanied with asthenopic symptoms so that one cannot read long without the letters running together;with pain deep in the eye. Excessive photopsies, but fundus normal in appearance. Photophobia. Everything looks white.
Natrum mur.- Hyperaesthesia of the retina especially from reflex irritation in chlorotic females there is great photophobia, with muscular asthenopia; some conjunctival injection eyes feel stiff and ache on moving them or on reading letters run together on attempting to read sticking throbbing headache in the temples.
Nux vomica.- When the photophobia is excessive in the morning and better as the day advances.
Ignatia.- Hyperaesthesia of the retina in nervous hysterical patient. Great dread of light and severe pain around the eye.
Lactic acid.- Hyperaesthesia of the retina with steady aching pain in and behind the eyeball.
Macrotin.- Angell considers Macrotin more widely service able than any one remedy. The ciliary neuralgia is usually marked.
Merc sol.- Eyes more sensitive to artificial light, and in the evening.
A large number of remedies which produce marked photophobia may be indicated by the general symptoms and cachexia of the patient as Aconite, Antimon. tart., Arsenicum China., Gelsemium, Hepar, Hyoscyamus, Pulsatilla, Rhus., Sepia Sulph. etc.
Commotio Retinae.- This terms is applied to sudden loss of vision from blows or concussion of the eyeball. An injury from a blow upon the eye may results in an almost complete loss of vision without any immediate evidence of damages having been done although, after a time, there may be signs of atrophy of the nerve. In more moderate injuries such as from cork of a bottle, there may be slight ciliary injection, some contraction and sluggishness of the iris and a grayish haziness of the retina, especially in the region of the macula. This opacity of the retina is of the considerable size is due to an acute oedema of the retina which comes on within a few hours and disappears after two or three day. There may be a decrease in the size of the arteries and an enlargement of the veins. Vision may be more or less affected and is not perfectly regained until the opacity of the retina has disappeared.
Glioma Retinae. (Fungus Haematodes of the Eye, Encephaloid of the Retina).- Gliomata are the only tumors arising from the retina, and they take origin from the connective tissue or neuroglia of the retina.
PATHOLOGY.- It consists of small cells with large nucleus and minute processes similar to those of the granular layers of the retina, numerous blood-vessels and a small amount of connective tissue. A glioma most often originates from the inner granular layer, although it may have its starting point in any of the layers of the retina; it may extend either outward from its place of origin and its special path of extension is along the optic nerve. Its histological features are similar to small, round celled sarcoma and is often called a glio-sarcoma.
Professor of Ophthalmology in the College of the New York Ophthalmic Hospital; Surgeon to the New York Ophthalmic Hospital. Visiting Oculist to the Laura Franklin Free Hospital for Children; Ex-President American Homoeopathic Ophthalmological, Otological and Laryngological Society. First Vice-President American Institute of Homoeopathy : President Homoeopathic Medical Society of the State of New York ; Editor Homoeopathic Eye. Ear and Throat Journal : Associate Editor. Department of Ophthalmology, North American Journal of Homoeopathy, etc.