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a thing seen.
far sight hyperopia.
near sight myopia.
night sight hemeralopia.
Inability to see as distinctly in a bright light as in reduced illumination; seen in patients with impaired cone function.
[G. hēmera, day, + alaos, obscure, + ōps, eye]
Term used to mean either night blindness in which there is a partial or total inability to see in the dark associated with a loss of rod function or vitamin A deficiency; or day blindness in which there is reduced vision in daylight while vision is normal in the dark. Syn. nyctalopia (this term is only synonymous with night blindness); night sight (this term is only synonymous with day blindness). See girate atrophy; congenital stationary night blindness; choroideremia; Oguchi's disease; retinitis pigmentosa.