Prevention of blindness (PBL). Prevalence and causes of blindness and low vision.
D000368:Aged; D001766:Blindness / Q000453:epidemiology* / Q000517:prevention & control; D006801:Humans; D008875:Middle Aged; D009018:Morocco / Q000453:epidemiology; D015354:Vision, Low / Q000453:epidemiology*