The Optic Nerve.
Disease may occur in the nerve, in the chiasm, or in the tract, and is always serious in character, suggesting tumors, syphilis, meningitis, or hemorrhages.
Etiology.—Optic neuritis is generally secondary, and may be regarded as a symptom of a serious cerebral disturbance. While in rare instances it may be primary, the result of cold and exposure, Gowers and Bramwell claim that eighty per cent are associated with cerebral tumors.
It sometimes occurs in the course of certain infectious fevers, notably scarlet fever, measles, enteric fever, and syphilis, and is also found in Bright's disease, leukemia, and diabetes.
Pathology.—Congestion of the disk (choked disk, papillitis), with its accompanying blurred or hazy condition, is seen in the early stage of optic neuritis; as the disease progresses the swelling increases and hemorrhages are not uncommon. If the inflammation be slight, resolution and restoration of the nerve take place, but more frequently it results in complete atrophy of the nerve. The retina may become involved, giving rise to neuro-retinitis.
Symptoms.—There are no characteristic symptoms, that can be recognized, if we except an ophthalmoscopic examination, and the latter must invariably be made before we can be certain of our diagnosis.
Prognosis.—The prognosis is not very favorable, for while mild cases may recover, they usually terminate with partial loss of vision, and the severer cases result in total blindness.
Treatment.—Where the cause is specific, potassium iodid, echinacea, stillingia, phytolacca, Donovan's solution of arsenic, and kindred remedies will be given; otherwise the treatment is symptomatic.