The proposed plan centers around understanding (1) the implication of polyolpathway of glucose metabolism in human lens physiology, particularly its role if any in the development of cataracts in human diabetes. Activities of various enzymes such as aldose reductase, polyol dehydrogenase and of the relevant substrates and cofactor nucleotides will be determined in normal and diabetic (cataractous and noncataractous) lenses. These studies will be extended further to examine the status of various factors involved in protecting the lens against oxidative stress, such factors being superoxide dismutase, peroxidase, catalase, ascorbic acid, and vitamin E, etc. The estimation of these constitutents will be done in normal and cataractous lenses. The potential of the lens to oxidative damage will also be assessed by determining fatty acid profile and the content of polyconjugated unsaturated residues. These studies will be supplemented by fluorometric determination of lipofuschin like material. All determinations are intended to be correlated with CCRG cataract classification.