Epidemiology of eye disease in the elderly.

Most of the estimated 40 million blind individuals in the world are in the older age groups. Data on blindness and visual impairment are primarily from blindness registries and prevalence surveys in different countries throughout the world. The quality of these data vary tremendously from one country to another, and comparability of the results from different studies is difficult. However, all studies indicate an increase in the prevalence of visual loss and blindness with increasing age. Cataract is the most prevalent eye disease in the world and is a major cause of visual loss in developing as well as in developed countries. Other major eye diseases in the elderly include age related macular degeneration, glaucoma, and diabetic retinopathy. A number of risk factors have been suggested for cataract, age related macular degeneration, and glaucoma, yet few have been well established. Certain factors for these conditions are similar, including age, hypertension, prolonged exposure to sunlight, and nutritional factors such as Vitamin E. Epidemiologic studies are needed to define the risk factors for these different eye diseases with the goal of decreasing risk of disease and possible disease prevention, as well as developing better estimates of the magnitude of the problems of visual loss and eye diseases in the elderly.