Historical: the qualitative approach.
D000293:Adolescent; D000328:Adult; D000867:Anterior Chamber; D002648:Child; D002675:Child, Preschool; D003315:Cornea; D004200:Diseases in Twins; D005123:Eye / Q000254:growth & development; D005260:Female; D014644:Genetic Variation; D006801:Humans; D006956:Hyperopia / Q000453:epidemiology; D007223:Infant; D007231:Infant, Newborn; D007908:Lens, Crystalline; D008297:Male; D009216:Myopia / Q000453:epidemiology; D012029:Refraction, Ocular; D012030:Refractive Errors / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics