WHO definition of 'blindness'
- WHO in 1972 proposed a universal definition of blindness – ‘a visual acuity of less than 3/60 (snellen) or its equivalent’
- In case snellen’s chart / other equipments are not available, blindness can be tested by – ‘visiual acuity less than counting fingers in day light at a distance of 3 meters’ – it is considered equivalent to 3/60 with snellen’s chart
- If the visual field is less than 10 degrees, irrespective of the level of visual acuity, it is considered as blindness
