Nyctalopia


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nyctalopia

[‚nik·tə′lō·pē·ə]
(medicine)

Nyctalopia

 

night blindness, a visual disorder manifested by partial or total inability to see objects in the twilight or at night.

Nyctalopia may arise in connection with certain organic diseases of the retina, choroid coat, or optic nerve, or with glaucoma (symptomatic nyctalopia); in connection with poor general nutrition due to starvation, certain liver diseases, malaria, alcoholism, or other conditions accompanied by a deficiency or total absence of vitamin A (functional nyctalopia); or in connection with congenital pigment degeneration of the retina (congenital nyctalopia). The immediate cause of nyctalopia is connected with structural changes in the retinal rods or a deficiency of rhodopsin (visual purple), which disintegrates in the light but is restored in the dark in the presence of vitamin A. Nyctalopia patients suffer from photophobia in bright light and sharply reduced vision in the twilight and at night. They may also suffer from reduced color sensitivity with respect to blue and yellow. Sometimes their visual field is narrowed and its acuity diminished. Nyctalopia is usually exacerbated in early spring because of insufficient vitamin A in the food.

A fully balanced diet, cod liver oil, and intake of vitamins A, B1, B2, and C are important to both treatment and prevention. In cases of symptomatic nyctalopia the causative disease should be treated.

REFERENCE

Katsnel’son, A. B. Vitaminy i avitaminozy v oftal’mologii.[Cheliabinsk] 1947.

S. I. TAL’KOVSKII

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References in periodicals archive ?
Clinically, this family experienced nyctalopia at start of 2nd decade of age among all affected individuals with uniform pattern which masked the complete vision in progressive age.
In a span of 2 years, 340 clinical cases of dogs underwent detailed ophthalmic examination for various ocular abnormalities which included complete history pertaining to visual abnormality including onset of troubled vision, nyctalopia, hemeralopia etc.
Kamran Ahsan, Obaid Khan and Abdul Salam of the Federal Urdu University of Arts, Science and Technology, in Karachi, explain how night blindness, nyctalopia, afflicts millions and may be present at birth as a genetic disease, arise in childhood through malnutrition or injury or be a symptom of numerous eye diseases.
But Herr Stark, probably suffering from nyctalopia, or night blindness, awarded United a penalty in the 52nd minute for a very feeble tackle on 22-year-old Brazilian defender Rafael Pereira da Silva by striker Burak Yylmaz, who had come back to help his defenders.
Affected individuals first experience defective dark adaptation or nyctalopia (night blindness), followed by reduction of the peripheral visual field (known as tunnel vision) and, sometimes, loss of central vision late in the course of the disease.
(107.) A less certain example is the personal defect smrmr' (with sycmc), perhaps to he vocalized smarmore, 'nyctalopia, night blindness' (SL 1576: LS 787b.
Ele e essencialmente o nao lugar, e desafia nossas concepcoes de distancia e de proximidade no que ele admite a ubiquidade e a metamorfose, a "retrovisao" e a "nyctalopia" dos seres-forca dos quais se presume o povoar.
RP was diagnosed based on the presence of the following characteristics [1,18-20]: (1) symptoms of nyctalopia; (2) pigmentary deposits resembling bone spicules originating from the peripheral retina, attenuation of the retinal vessels, waxy pallor of the optic disc, and various degrees of retinal atrophy, demonstrated by funduscopy; and (3) dramatic reductions in a-wave and b-wave amplitudes affecting the scotopic system (rods) to a greater extent than the photopic system (cones), demonstrated by electroretinography.