Nyctalopia

Common card · No. 229658

Nyctalopia (; from Ancient Greek νύκτ- (núkt-) 'night', ἀλαός (alaós) 'blind, invisible' and ὄψ (óps) 'eye'), also called night blindness, is a condition making it difficult or impossible to see in relatively low light. It is a symptom of several eye diseases. Night blindness may exist from birth, or be caused by injury or malnutrition (for example, vitamin A deficiency). It can be described as insufficient adaptation to darkness. The most common cause of nyctalopia is retinitis pigmentosa, a disorder in which the rod cells in the retina gradually lose their ability to respond to the light. Patients with this genetic condition have progressive nyctalopia and, eventually, their daytime vision may also be affected. In X-linked congenital stationary night blindness, from birth the rods either do not work at all, or work very little, but the condition does not get worse. Another cause of night blindness is a deficiency of retinol, or vitamin A1, found in fish oils, liver, and dairy products...

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