Some global aspects of blindness.
D000293:Adolescent; D000328:Adult; D001766:Blindness / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D002386:Cataract / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003906:Developing Countries; D006801:Humans; D007223:Infant; D008875:Middle Aged; D009855:Onchocerciasis / Q000453:epidemiology; D014141:Trachoma / Q000453:epidemiology; D014802:Vitamin A Deficiency / Q000453:epidemiology