The eyes need vitamin A or its precursors, beta carotene, as well as bioflavonoids, to make the pigments that absorbs light within the eye. A deficiency in vitamin A, or a failure to utilize it properly, impairs the eyes ability to adapt to darkness and leads to night blindness. this does not entail a total loss of night vision, but rather difficulty seeing well in dim lighting.
Vitamin A deficiency is rare in the Western world, but it remains a major problem in many underdeveloped countries. Organs meats, fortified margarine,butter and other dairy products are good sources of vitamin A. Dark yellow or orange foods, such as carrots, sweet potatoes, and apricots as well as dark green leafy vegetables, are the richest sources of beta carotene, which the body converts to vitamins A.