<prompt> Blindness is defined at:18-MarJan-60Jun-60Mar-60  <response>: 360: Ref: 349-Park 20thWHO defined blindness: - Inability to count fingers in day light at distance of 3 meters to indicate less than 360 or its equivalent.Categories of visual impairmentCategories of visual impairmentVisual acuity Maximum less thanMinimum equal to or better thanLow vision1 618660 2 660360Blindness3 360 finger counting at 3 meters4 160 finger counting at 1 meter5 No light perception160 finger counting at 1 meterLight perception Cataract: is the most common cause of the blindness in India Refractive error: is the most common cause of ocular morbidity in India Vision 2020: The right to sight, a global initiative to eliminate avoidable blindness was launched by WHO on 18 Feb. 1999. Target diseases are cataract, refractive errors, childhood blindness, corneal blindness, glaucoma, diabetic retinopathy. Four tier structure includeI Centers of excellence 20 -TertiaryII Tertiary centers 200 - TertiaryIII Service centers 2000 - SecondaryIV Vision centers 20000 - Primary 