Episcleral lipid deposits and scleral plaques in Japan (Kyoto).

Screening of 189 Mongolian Japanese of both sexes in all age groups for scleral degenerations revealed presence of lipid deposits, especially round the anterior ciliary vessels, in 52%. The prevalence exceeds that among Caucasians in Denmark (N = 689), Eskimos in Greenland (N = 340), and Arabs in Jordan (N = 127), all examined by the same worker employing the same technique. Scleral plaques (well-defined transparency anterior to horizontal muscle) is present in no more than 0.5% of Japanese. This phenomenon is likewise rare among Eskimos, but frequent among Caucasians. The causes of the geographic differences are discussed.