This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Non-Communicable Diseases, Subject name: Social & Preventive Medicine
WHO definition of blindness, Visual acuity - 
Select and explain. 
A. <6/60, B. < 3/60, C. <6/18, D. < 6/9
B: < 3/60
Answer: B: < 3/60 
Explanation: Ans. is 'b' i.e., < 3/60 o WHO defines blindness as "Visual acuity of < 3/60 in better eye with best possible correction".Categories of visual impairmentCategories of visual impairmentVisual acuityMaximum less thanMinimum equal to or better thanLow vision1. 6/182. 6/606/603/60Blindness3. 3/60 (finger counting at 3 metres)4. 1/60 (finger counting at 1 metre)5. No light perception1/60 (finger counting at 1 metres) light perception