Pterygium in Ceylon.
D000367:Age Factors; D002980:Climate; D005260:Female; D006801:Humans; D006813:Humidity; D008297:Male; D010044:Outpatient Clinics, Hospital; D011625:Pterygium / Q000453:epidemiology*; D012737:Sex Factors; D013188:Sri Lanka; D013472:Sunlight