Social & Preventive Medicine According to prevalence criteria for determining xerophthalmia problems given by WHO, following are true for an endemic area: A Bitot spot 5% poluation of under 6 yrs B Conjuctival xerosis 1% C Conjuctival ulcers 0.05% D Night blindness 1% 💡 Explanation According to prevalence criteria for determining xerophthalmia problems given by WHO, following are true for an endemic area: ✓ Correct Answer: D. Night blindness 1%