WHO Definitions and the Two Big Differences

WHO definitions

The World Health Organization defines blindness and low vision based on visual acuity and visual field:

CategoryVisual acuityVisual field
Moderate low vision> 2/20 and < 7/20 with best correction> 20°
Severe low vision< 2/20 or equal to 1/20 with best correction> 10° but < 20°
Blindness< 1/20 with best correction< 10°
Deep blindnessNo light perception — no movement perceptionNot evaluable

The two big differences

Blind person

  • A person with total or partial loss of vision
  • Has the perception of light and shadow but not of shapes

Low vision person

  • Has residual vision
  • Many different ways of seeing
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