Definition of nyctalopia in English:



  • [mass noun] A condition characterized by an abnormal inability to see in dim light or at night, typically caused by vitamin A deficiency.

    • ‘Fundus examination is usually normal, distinguishing it from the progressive conditions causing nyctalopia.’
    • ‘About 90% of the female portion of the study suffer from Nyctalopia.’
    • ‘The insensitivity to dim stimuli is accompanied by a mild nyctalopia.’
    • ‘Ophthalmologists are occasionally confronted with an individual presenting with nyctalopia (ie, a relatively greater difficulty seeing at night).’
    • ‘The fact that an abnormal result occurs in 26%, however, suggests that ncytalopia should be evaluated with electrophysiological testing even when the fundi appear normal.’


Late 17th century: via late Latin from Greek nuktalōps, from nux, nukt- night + alaos blind + ōps eye.