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  2. Nyctalopia - Wikipedia

    en.wikipedia.org/wiki/Nyctalopia

    Night blindness may exist from birth, or be caused by injury or malnutrition (for example, vitamin A deficiency). It can be described as insufficient adaptation to darkness. The most common cause of nyctalopia is retinitis pigmentosa, a disorder in which the rod cells in the retina gradually lose their ability to respond to the light. Patients ...

  3. Vitamin A deficiency - Wikipedia

    en.wikipedia.org/wiki/Vitamin_A_Deficiency

    Vitamin A plays a major role in phototransduction, so this deficiency impairs vision, often presenting with nyctalopia (night blindness). [1] In more severe VAD cases, it can progress to xerophthalmia, keratomalacia, and complete blindness. [1] Vitamin A deficiency is the leading cause of preventable childhood blindness worldwide and is a major ...

  4. Xerophthalmia - Wikipedia

    en.wikipedia.org/wiki/Xerophthalmia

    The causes are vitamin A deficiency during pregnancy, followed by low transfer of vitamin A during lactation and infant/child diets low in vitamin A or beta-carotene. [4] [5] The prevalence of pre-school age children who are blind due to vitamin A deficiency is lower than expected from incidence of new cases only because childhood vitamin A ...

  5. Adaptation (eye) - Wikipedia

    en.wikipedia.org/wiki/Adaptation_(eye)

    Night blindness can be caused by a number of factors the most common of which being vitamin A deficiency. If detected early enough nyctalopia can be reversed and visual function can be regained; however; prolonged vitamin A deficiency can lead to permanent visual loss if left untreated. [55]

  6. Childhood blindness - Wikipedia

    en.wikipedia.org/wiki/Childhood_blindness

    This vitamin deficiency blinds hundreds of thousands of kids each year, and is a preventable cause of childhood blindness. Since vitamin A is required for rhodopsin, the photosensitive pigment in the retinol rods, its deficiency can lead to night blindness. [8]

  7. Vitamin A - Wikipedia

    en.wikipedia.org/wiki/Vitamin_A

    An early sign of vitamin A deficiency is night blindness. [6] Vitamin A in the form of retinoic acid is essential to normal epithelial cell functions. Severe vitamin A deficiency, common in infants and young children in southeast Asia causes xerophthalmia characterized by dryness of the conjunctival epithelium and cornea. Untreated ...

  8. Rod cell - Wikipedia

    en.wikipedia.org/wiki/Rod_cell

    As the retinal component of rhodopsin is derived from vitamin A, a deficiency of vitamin A causes a deficit in the pigment needed by rod cells. Consequently, fewer rod cells are able to sufficiently respond in darker conditions, and as the cone cells are poorly adapted for sight in the dark, night-blindness can result.

  9. Vitamin K deficiency - Wikipedia

    en.wikipedia.org/wiki/Vitamin_K_deficiency

    Vitamin K 1-deficiency may occur by disturbed intestinal uptake (such as would occur in a bile duct obstruction), by therapeutic or accidental intake of a vitamin K 1-antagonist such as warfarin, or, very rarely, by nutritional vitamin K 1 deficiency. As a result, Gla-residues are inadequately formed and the Gla-proteins are insufficiently active.