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"The principal and perhaps only disease of the human lens is the opacification of the lens—a cataract. However, approximately 60% of persons between the ages of 65 and 74 [years] in the United States show some signs of cataract development, and cataracts are the leading cause of blindness in Africa," reported William Rathbun, PhD, associate professor, Department of Ophthalmology, University of Minnesota Medical School, Minneapolis, in discussing "The Achilles Heel of the Human Lens" at the Research to Prevent Blindness seminar in Washington, DC.
Cataracts may be unavoidable. Ultraviolet light, present in sunlight and many forms of artificial light—when incident on the lens—produces free radicals and oxidation products such as hydrogen peroxide, that lead to the development of cataracts.
An apparent defense mechanism in the young, healthy lens is a tripeptide—glutathione. Work in Rathbun's laboratory has demonstrated that the glutathione content of the lens decreases with age. That "concentration has
Cole H. Enzyme activity may hold key to cataract prevention. JAMA. 1985;254(8):1008. doi:10.1001/jama.1985.03360080018004