The incidence of cataract in Nepal was determined from data collected in 14 mobile eye hospitals (called 'eye camps'). Of a total of 12,217 patients examined in the out-patient department (OPD), cataract surgery was performed on 2,163. The percentage of cataract patients in the OPD was less in the mountains (13.8%) than in the Tarai plains (19.8%). In the inhabitants of the mountains, the majority of whom belong to the Tibeto-Birman race, cataracts appeared at a significantly later age in both males and females compared to the people of the plains, who are mostly Indo-Aryan. Cataracts were discovered in both groups at a younger age in women than in men.