This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
[{'content': 'If blindness is surveyed using schools as compared to population surveys, then estimation of prevalence of blindness will have ? \nSelect and explain. \nA. Overestimation, B. Underestimation, C. Remains same, D. None of them is used for evaluation', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Blindness situation in India\n\nEstimated prevalence of blindness in India (total) : 11.2 per 1000 population.\nEstimated prevalence of blindness in India (0-14 years) : 0.1 per 1000 population.\nEstimated prevalence of blindness in India (15-49 years) : 0.6 per 1000 population.\nEstimated prevalence of blindness in India (50+ years) : 77.3 per 1000 population.\nSo if schools are used where only refractive errors generally constitute blindness (that too very few are actually blind i.e. <6 / 60) As compared to population (where age-related cataract constitute as major cause of blindness), it would lead to underestimation of prevalence of blindness in the country.', 'role': 'assistant'}]