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 ability to see in dim light or at night is an important part of our visual health. When we are not able to do such, the condition is referred to commonly as night blindness or medically as nyctalopia. It occurs as a result of various diseases that cause degeneration of the rods of the retina (the sensory cells responsible for vision in dim light). The problem can also appear as an inherited deficiency in visual purple, or rhodopsin, which is the pigment of the rods of the retina. The abnormality can also result from vitamin A deficiency. Rhodopsin, maintains its photosensitivity only in the presence of vitamin A. Night blindness is a classic finding from deficiency of vitamin A. It was described by the English physician William Heberden (1710-1801) who also discovered other medical disorders of importance including angina pectoris (chest pain that is often severe and crushing, due to an inadequate supply of oxygen to the heart muscle) and osteoarthritis of the small joints with nodules (Heberden’s nodes) in and about the last joint of the finger. Sources of vitamin A include animal livers, milk, and yellow and green leafy vegetables which contain carotenes, chemically related substances that are converted to vitamin A in the body. "Nyctalopia" comes from the Greek "nyct" (night) + "aloas" (obscure or blind) + "opsis" (vision). Nyctalopia is also called day sight, nocturnal amblyopia, and nyctanopia.
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Decreased ability to see in reduced illumination. Seen in patients with impaired rod function; often associated with a deficiency of vitamin A. SYN: day sight, night blindness, nocturnal amblyopia, nyctanopia. [nyct- + G. alaos, obscure, + ops, eye]
- n. with congenital myopia [MIM*310500] an abnormality of X-linked inheritance characterized by low visual acuity, strabismus, or nystagmus.

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nyc·ta·lo·pia .nik-tə-'lō-pē-ə n NIGHT BLINDNESS

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n.

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nyc·ta·lo·pia (nik″tə-loґpe-ə) [nyct- + Gr. alaos blind + -opia] night blindness; failure or imperfection of vision at night or in a dim light, with good vision only on bright days.

Medical dictionary. 2011.

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 —    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… …   Dictionary of Hallucinations

  • 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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