ANGIOID STREAKS in the retina, brownish streaks of pigment-deposit which have the shape of a vascular net work, but which do not conform to either the retinal or choroidal vessels, mark a special form of a retinal degeneration. is impaired, and the streaks are preceded by retinal limmorrhages Diagnosis.—Retinitis must not he con fused with blurring of the retinal vessels and other details of the fundus due to errors of refraction, especially regular astigmatism. Blurring from an error of refraction affects all parts of the fundus, or all parts of the retinal vessels running in a certain direction. Retinitis affects only certain portions of the fundus, or some parts more than others, and veils the vessels running in one direction no more than those running in another. The haziness caused by dust-like, local ized opacities of the vitreous simulates that of retinitis. Patches of serous ret initis may closely resemble detachment of the retina. The appearance of the retinal vessels upon the surface, with prominence of the swelling and the in volvement of a large area, indicates de tachment.
Retinitis is generally followed by de generative changes, and many of the symptoms characterizing its various forms are really degenerative. The di agnosis between the different varieties is indicated in their description. In de termining the form of the retinitis other symptoms of the underlying general con dition should also be sought for and care fully considered. Thus albuminuric retinitis may be exactly simulated by the retinal symptoms of organic disease of the brain; and only the renal or the cerebral symptoms can establish the di agnosis.
Prognosis.—This depends on the cause of the retinitis. Simple inflammation
from eye-strain may end in complete recovery. Purulent retinitis commonly destroys the eyeball, but the form char acterized by small, white spots may go on to incomplete recovery. Albuminuric and leukTmic retinitis may improve under treatment, but they partake of the grave prognosis of the underlying dis eases. Albuminuric retinitis arising dur ing pregnancy may undergo very marked improvement. Retinitis pigmentosa goes slowly on to hopeless blindness. Other forms of retinitis rarely cause complete blindness; but the vision once lost through them is not regained, or is only partly recovered.
Treatment. — Rest for the eyes and avoidance of bright light and sudden changes of illumination are important, in the active stages of retinal inflamma tion. Rest must include the use of lenses correcting any ametropia, and may re quire the use of colored glasses or a cycloplegic. Removal of the cause or appropriate treatment of the underlying dyscrasia comes next in importance. After the acute stage has passed, the retinal degeneration succeeding it is best met by tonics, and especially strychnine in doses ascending to near the limit of physiological tolerance. Retinitis pig mentosa requires a very moderate use of the eyes and the tonic treatment throughout. Instillations of a weak so lution of physostigmine may be em ployed; and the application of a weak galvanic current, to 1 milliampere, has been credited with benefit.
Embolism and Thrombosis of the Cen tral Retinal Artery.—These cause sud den blindness of one eye, usually perma nent.