Assessment of xerophthalmia and the mass vitamin A prophylaxis program in El Salvador (September 1973--December 1974).
D002648:Child; D002675:Child, Preschool; D004544:El Salvador; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D014801:Vitamin A / Q000627:therapeutic use*; D014985:Xerophthalmia / Q000453:epidemiology / Q000517:prevention & control*
D014801:Vitamin A