Prevalence of lens opacities in surgical and general populations.

The distribution and prevalence of lens opacities were examined and compared among three general population-based groups and a group that underwent cataract surgery. The population-based groups comprised subjects from the Framingham Eye Survey, the National Health and Nutrition Examination Survey, and the study of watermen in Maryland. Comparison among these groups revealed similar frequencies of lens opacities among age groups, with slightly higher rates for older individuals in the watermen study population. Comparison between the watermen and the surgical groups revealed that, of lenses with opacities, posterior subcapsular cataracts were present in a far greater percentage of surgery cases (60.6%) than in general population cases (5.3%). These findings confirm the generally held clinical belief that posterior subcapsular opacities are disproportionally represented in the surgical population and suggest that they cause more significant visual disability than do other types of cataracts.