(nyctalopia) the inability to see in dim light or at night. It is due to a disorder of the cells in the retina that are responsible for vision in dim light (see rod), and can result from dietary deficiency of vitamin A. Vitamin A deficiency may progress to cause xerophthalmia and keratomalacia. Night blindness may be caused by other retinal diseases, e.g. retinitis pigmentosa. Congenital stationary night blindness is characterized by poor night vision from early childhood that does not get worse, in association with nystagmus. Compare day blindness.
Subjects: Medicine and Health — Science and Mathematics.