Which is a preventable cause of blindness -

Ans. is 'b' i.e., Vitamin A deficiency Avoidable blindness -* Avoidable blindness is defined as blindness which could have been either treated or prevented by known cost effective means.* Thus avoidable blindness is divided into:1) Treatable blindness# Treatable are those condition that could have been treated early to prevent blindness, i.e. secondary prevention - early diagnosis & treatment to prevent disability (blindness).# Important causes of treatable blindness are cataract, glaucoma, amblyopia, retinopathy of prematurity, refractive errors, and diabetic retinopathy2) Prevantable blindness# Preventable are conditions that are amenable to primary prevention, i.e. where the condition causing blindness could have been entirely prevented.# Important causes of preventable blindness are measles, vitamin A deficiency, ophthalmia neonatrum. and trachoma.