More than 90% of diabetic patients with poor glycemic controls for many years develop retinopathy. In diabetic retinopathy, free radicals are generated by autoxidation reactions of sugar and by autoxidation of unsaturated lipids in plasma and membrane proteins. Elevated generation of NO in ocular vessels of the perinate facilitates peroxynitrite formation with its deleterious effects including increased lipid peroxidation and platelet aggregation. The enhanced consumption of ascorbic acid results in increased oxidation of ascorbic acid to dehydroascorbic acid to scavenge increased free...