nyctalopia
   Also known as moonblink and night blindness. The term nyctalopia comes from the Greek words nux (night), alaos (blind), and ops (eye). The first known reference is found in the book Epidemics of the Hippocratic Corpus. In the Hip-pocratic Corpus, as well as in the Anglo-Saxon literature, the term nyctalopia is characterized as an impairment of nocturnal vision due to defective dark adaptation, while the affected individual's vision in bright light remains unaffected. Nyctalopia is usually classified as an *entoptic phenomenon. Pathophysiologically, it is associated primarily with a loss or impairment of rod photoreceptor function. Etiologically, it is associated primarily with a variety of acquired conditions such as vitamin A deficiency, retinitis pigmentosa, Usher's syndrome, and cancer-associated retinopathy. The condition may also be congenital, as in X-linked congenital stationary night blindness. Conceptually, nyctalopia constitutes the logical counterpart of * hemeralopia (i.e. day blindness). In the continental European literature (notably the French, Italian, and Greek literature) the term nyctalopia is used to denote a relative improvement of vision at night. This paradoxical connotation was noted by the physician Galen of Pergamum, born as Claudius Galenus (129-c. 216), who wrote, "Nyctalopia is the condition when someone can see neither in the moon's light nor in the light of lanterns... but so also call a disease where the opposite is observed, namely to see better at night than the day. Some confirm that the word that describes night blindness is also used for these patients, so that eventually the word describes two kinds of diseases: the disease where we do not see at night and the one where we do not see during the day." It has been suggested that the connotation of day blindness was prompted by an alternative etymology in which the term nyctalopia translates as night vision (from the Greek words nux (night) and ops (eye)). Apparently, in some European countries this version turned out to be the more influential one. Nevertheless, it would seem advisable to adhere to the original connotation of nyctalopia as a defective dark adaptation, or, alternatively, to use the term night blindness.
   References
   Brouzas, D., Charakidas, A., Vasilakis, M., Nikakis, P., Chatzoulis, D. (2001). Nyctalopia in antiquity: A review of the ancient Greek, Latin, and Byzantine literature. Ophthalmology, 108, 1917-1921.
   Ohba, N., Ohba, A. (2006). Nyctalopia and hemeralopia: The current usage trend in the literature. British Journal of Ophthalmology, 90, 1548-1549.

Dictionary of Hallucinations. . 2010.

Look at other dictionaries:

  • Nyctalopia — Classification and external resources ICD 10 H53.6 ICD 9 368.6 Nyctalopia (from Gree …   Wikipedia

  • Nyctalopia — Nyc ta*lo pi*a (n[i^]k t[.a]*l[=o] p[i^]*[.a]), n. [L. nyctalopia, fr. nyctalops a nyctalops, Gr. nykta lwps. Gr. nykta lwps meant, a person affected either with day blindness or with night blindness, and in the former case was derived fr. ny x,… …   The Collaborative International Dictionary of English

  • nyctalopia — [nik΄tə lō′pē ə] n. [LL < Gr nyktalōps < nyx (gen. nyktos), NIGHT + alaos, blind (< a , not + laein, to see) + ōps, EYE] NIGHT BLINDNESS: cf. HEMERALOPIA nyctalopic [nik΄təläp′ik] adj …   English World dictionary

  • Nyctalopia — Night blindness, impaired vision in dim light and in the dark, due to impaired function of certain specialized vision cells (the rods) in the retina. The ability of our eyes to quickly view objects as they shift from light to dark areas and the… …   Medical dictionary

  • nyctalopia —    Night blindness. Nyctalopia comes to us from the Latin word nyctalops, which means suffering from night blindness. It is ultimately derived from the Greek word nyktalops, which was formed by combining the word for night ( nyx ) with the words… …   Glossary of Art Terms

  • nyctalopia — Moonblink Moon blink , n. A temporary blindness, or impairment of sight, said to be caused by sleeping in the moonlight; sometimes called {nyctalopia}. [1913 Webster] …   The Collaborative International Dictionary of English

  • nyctalopia — nyctalopic /nik tl op ik/, adj. /nik tl oh pee euh/, n. Ophthalm. 1. See night blindness. 2. hemeralopia. [1675 85; < LL nyctalopia < Gk nykt NYCT + al(aós) blind + opia OPIA] * * * …   Universalium

  • nyctalopia — nyc•ta•lo•pi•a [[t]ˌnɪk tlˈoʊ pi ə[/t]] n. 1) oph night blindness 2) oph hemeralopia • Etymology: 1675–85; < LL nyctalōpia < Gk nykt , s. ofnýx night+al(aós) blind + ōpia opia nyc ta•lop′ic ˈɒp ɪk adj …   From formal English to slang

  • nyctalopia — noun Etymology: New Latin, from Latin nyctalops suffering from night blindness, from Greek nyktalops, from nykt , nyx night + alaos blind + ōp , ōps eye more at night, eye Date: 1684 night blindness …   New Collegiate Dictionary

  • nyctalopia — noun The inability to see clearly in dim light; night blindness …   Wiktionary

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