[Epidemiologic study of vernal keratoconjunctivitis in the northwest region of China].
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D002681:China; D002980:Climate; D003233:Conjunctivitis, Allergic / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D012494:Sampling Studies