Overview:
People with night blindness (also called impaired dark adaptation) typically see poorly in the darkness but see normally when adequate amounts of light are present. This condition unless accompanied by other eye pathology does not usually involve true blindness, even at night.
Night blindness may be an early sign of vitamin A deficiency. Such a deficiency may result from diets low in animal foods (the main source of vitamin A), such as eggs, dairy products, organ meats, and some fish. Low intake of fruits and vegetables containing beta-carotene, which the body converts into vitamin A, may also contribute to a vitamin A deficiency. Doctors often recommend 10,000 to 25,000 IU of vitamin A per day to correct a deficiency. Beta-carotene is less effective at correcting vitamin A deficiency than is vitamin A itself, because it is not absorbed as well and is only slowly converted by the body into vitamin A.
The best form of vitamin A is known as palmitate, taken in a daily dose of 15,000 international units.
Occasionally, night blindness can be an early symptom of a progressive eye disease. One example is retinitis pigmentosa (RP), which affects an estimated 100,000 people in the United Sates.
Dietary zinc deficiency is common, and a lack of zinc may reduce the activity of retinol dehydrogenase, an enzyme needed to help vitamin A work in the eye. Zinc helps night blindness in people who are zinc-deficient;(1) therefore, many physicians suggest 15 to 30 mg of zinc per day to support healthy vision. Because long-term zinc supplementation may reduce copper levels, 1 to 2 mg of copper per day (depending on the amount of zinc used) is usually recommended for people who are supplementing with zinc for more than a few weeks.
Bilberry, a close relative of the blueberry, is high in flavonoids known as anthocyanosides. Anthocyanosides speed the regeneration of rhodopsin, the purple pigment that is used by the rods in the eye for night vision.(2) Supplementation with bilberry has been shown in early studies to improve dark adaptation in people with poor night vision.(3) (4) However, two newer studies found no effect of bilberry on night vision in healthy people.(5) (6) Bilberry extract standardized to contain 25% anthocyanosides may be taken in capsule or tablet form.
If you're having problems with night vision, you should have your eyes examined by an ophthalmologist.
- Anonymous. Zinc-responsive night blindness in sickle cell anemia. Nutr Rev 1982;40:175 7.
- Alfieri R, Sole P. Influencedes anthocyanosides admintres parvoie parenterale su l adaptoelectroretinogramme du lapin. CR Soc Biol 1964;15:2338 [in French].
- Jayle GE, Aubry M, Gavini H, et al. Study concerning the action of anthocyanoside extracts of Vaccinium myrtillus on night vision. Ann Ocul 1965;198:556 62 [in French].
- Belleoud L, Leluan D, Boyer YS. Study on the effects of anthocyanin glycosides on the nocturnal vision of air controllers. Rev Med Aeronaut Spatiale 1966;18:3 7.
- Zadok D, Levy Y, Glovinsky Y. The effect of anthocyanosides in a multiple oral dose on night vision. Eye 1999;13:734 6.
- Muth ER, Laurent JM, Jasper P. The effect of bilberry nutritional supplementation on night visual acuity and contrast sensitivity. Altern Med Rev 2000;5:164 73.
Symptoms:
May vary on an individual basis for each patient. Symptoms include difficulty seeing when driving in the evening or at night, poor vision in reduced light, and feeling that the eyes take longer to “adjust” to seeing in the dark. Only your doctor can provide adequate diagnosis of any signs or symptoms and whether they are indeed Night blindness symptoms.
Note that Night Blindness symptoms usually refers to various symptoms known to a patient, but the phrase Night Blindness signs may refer to those signs only noticable by a doctor.
Symptoms include difficulty seeing when driving in the evening or at night, poor vision in reduced light, and feeling that the eyes take longer to “adjust” to seeing in the dark.
Causes:
Possible causes of Night Blindness poor night vision): The following medical conditions are some of the possible causes of Night Blindness as a symptom. There are likely to be other possible causes, so ask your doctor about your symptoms.
- Retinitis pigmentosa
- Macular Degeneration
- Rod-Cone Dystrophy
- Catatacts
- Vitamin A deficiency
- Malabsorption - if it affects vitamin A absorption
- Celiac disease
- Cystic fibrosis
- Bile duct obstruction
- Cirrhosis of the liver
- Diabetes
- Cataracts
- Macular degeneration
- Severe short-sightedness
- Congenital night vision disorder
Complementary Treatment:
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