Total plasma homocysteine was measured at baseline, and after four and eight weeks. Blinded analyses revealed no evidence of toxicity in the group randomized to supraphysiologic dose B-vitamin supplementation. Supraphysiologic doses of B-vitamins may be required to correct hyperhomocysudy. It has long been known that an inadequate diet lacking in certain essential vitamins can cause ocular disorders. On an Egyptian papyrus dated about 1500 BC, it is recorded that liver was used as a food to cure night blindness.
Healthy eyes depend on a well-balanced diet.
Vitamin A maintains the normal function of the epithelial cells of the eye and is essential for the synthesis of visual photosensitive pigments. Deficiencies of vitamin A lead to clinical manifestations including night blindness, conjunctival pigmentation, and dry eyes. The B vitamins are important for maintaining good vision. Vitamin B12 deficiency can produce vascular changes in the retina. Vitamin C is necessary to prevent scurvy.