D defs.my
Entry 1 sense Webster, 1913

Nyctalopia

/(nĭk`tȧ*lō"pĭ*ȧ)/ · Nyc·ta·lo·pi·a · IPA /ˌnɪk.təˈloʊ.pi.ə/
01 n. A disease of the eye, in consequence of which the patient can see well in a faint light or at twilight, but is unable to see during the day…
  1. 1.
    A disease of the eye, in consequence of which the patient can see well in a faint light or at twilight, but is unable to see during the day or in a strong light; day blindness.(Med.)