Nutrition and The Eye

. Friday, January 9, 2009
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The value of dietary sources of vitamin A for the prevention of night-blindness was known to the ancient Egyptians. Since then dietary supplement have been shown to benefit the eyes in only a small number of additional situations.

Vitamin A is required for the synthesis of the pigments which absord light within the eye, as well as for the maintenance of the eye’s smooth surface. The initial sign of vitamin A deficiency is usually night-blindness, followed in severe cases by dry eyes, and ultimately, breakdown of the ocular surface. Fortunately, vitamin A is plentiful in most diets, and symptoms are rare. Nearly all of the cases in developed countries result from malabsorption of the vitamin due to an intestinal disorder. Oral or injectable supplement typically bring dramatic improvement. In developing countries, diets deficient in vitamin A remain a major cause of visual disability. Inexpensive supplementation programs have proven very effective.

Recently, it has been reported that vitamin A may be of some value in slowing the rate of loss of vision in retinitis pigmentosis, a rare, inherited disease of the retina. The effect was small, and the dosage used was nearly 60 percent of the potentially toxic dose. In the same study, vitamin E supplements appeared to slightly accelerate the loss of retinal function.

It has also been suggested that vitamins E and C, as well as Zinc and other antioxidant and macular degeneration. In one preliminary study, high does zinc supplements appeared to reduce the incidence of onset of macular degeneration, thought they had no effect on the progress of established disease. Confirmatory studies are in progress.

There is no convincing evidence that any vitamin or mineral supplement is of value in the prevention or treatment of cataract.(Scott E. Brodie, MD.,Ph.D.)


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