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
According to WHO. blindness is defined as a visual acuity of the better eye, less than - 
Select and explain. 
A. Jun-60, B. May-60, C. Apr-60, D. Mar-60
D: Mar-60
Answer: D: Mar-60 
Explanation: Ans. is 'd' i.e., 3/60 Blindnesso WHO has proposed a uniform criterion and defined blindness as "Visual acuity of less than 3/60 or its equivalento In the absence of appropriate vision charts, the WHO has now added the "inability to count fingers in daylight at a distance of 3 metres" Xo indicates less than 3/60 or its equivalent.