NIGHT BLINDNESS

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.

   Failing night vision should not be self-treated wit vitamin A or beta carotene supplements; the problem may stem from a digestive or malabsorption disorder that prevents the body from using the vitamin. Treatment or the  underlying cause usually cures the night blindness. An exception is night blindness caused by retintis pigmentosa, a genetic disease. However, recent research suggest that the vitamin A may in fact, slow the progressive vision loss of this incurable disease.