Spheroid degeneration, keratopathy, pinguecula, and pterygium in Japan (Kyoto)

The prevalences of various possibly sunlight-induced degenerations of the exposed section of the eye have been studied in a series of 189 Japanese (Mongols) in Kyoto (subtropical climate, 35 degrees N. lat.). The results were compared with those of the author's examinations, using the same method and apparatus, in Jordan near the Red Sea (Arabs, N = 127) in Greenland (Eskimos, N = 659), and in Denmark (Caucasians, N = 810). In the Japanese series conjunctival spheroid degeneration was noticed in 31% and pinguecula in 60%, i.e. less frequently than in the sunny Jordan, but more frequently than in Greenland and Denmark. Climatokeratopathy was more rarely observed than in Greenland. This goes to show that the risk of corneal complications is lower in Japan despite the high prevalence of solar conjunctival degenerations. Pterygium was seen in a surprisingly small number of cases (1%), indicating that pterygium bears no relation to the conjunctival degenerations.