This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Health Programmes in India, Subject name: Social & Preventive Medicine
[{'content': 'Which is a preventable cause of blindness - \nSelect and explain. \nA. Cataract, B. Vitamin A deficiency, C. Refractive errors, D. Retinal dystrophies', 'role': 'user'}, {'content': "Answer: B \nExplanation: 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.", 'role': 'assistant'}]