Nictalopia

The causes of congenital nictalopia are not well understood. The cause of nictalopia is vitamin deficiency or hypovitaminosis A , as well as B1 and PP . Symptomatic nictalopia is observed in diseases of the retina (pigmented dystrophy, inflammatory lesions of the retina) and the optic nerve (atrophy, congestive disk), with glaucoma, etc. In the development of the disease, the process of restoration of visual purpur plays a role.

Weakened vision and spatial orientation at dusk. Decrease in light sensitivity, violation of the process of dark adaptation , narrowing of the fields of vision , especially in color. Diagnosis is based on complaints, clinical presentation, and laboratory findings.

With congenital nictalopia, a marked decrease in vision is noted. In the case of primary nictalopia, the prognosis is favorable, with symptomatic nictalopia it depends on the course and outcome of the underlying disease.

Congenital nictalopia is not treatable. In symptomatic nictalopia, the underlying disease is treated. In primary nictalopia, vitamin A administration is indicated inside: adults - 50-100 thousand ME per day, children - 1-5 thousand ME per day; at the same time, riboflavin is prescribed (up to 0.02 g per day). Prevention of primary nictalopia is an adequate intake of vitamin A.

Hemeralopia (from the Greek. Ημέρα , "day"; and Greek. Αλαός , "blindness") in accordance with the translation means a decrease in vision in daylight ( day blindness ). However, in most non-English-speaking countries (including Russia), the term hemeralopia has entrenched to describe poor vision at dusk and is synonymous with the term nictalopia ^[4] .

Hemeralopia is often called night blindness. The disease got its name because chickens and other daytime birds (sparrows, crows, pigeons and daytime predators) lack twilight vision .