An epidemiological survey of cataract was performed in a limited local population. 1,020 individuals over 40 years of age were examined. The crystalline lens findings were documented by both Scheimpflug and retroillumination photography. Cataractous changes were classified into three groups according to early senile changes, incipient cataractous changes and only prominent cataractous changes. Forms of opacification were classified as cortical, subcapsular, nuclear, mixed type and others. The percent prevalence of cataracts including early senile changes was 33.9% in the 40-year-old population, 62.8% in the 50, 76.2% in the 60, 84.0% in the 70 and 100% for those in their 80s. Prominent cataractous opacification was 1.6% in the 40-year-old population, 3.1% for those in their 50s, 19.0% in their 60s, 28.6% in their 70s and 57.1% in their 80s, respectively. Until age 60, the type of opacification was mainly cortical alone; however, after age 70, cortical opacity accompanied by nuclear and/or capsular opacities increased. The pure nuclear type increased in individuals over 70.