Blindness

**Definition:** The numerical definition used for WHO statistics refers to profound, near-total or total loss. The functional definition refers to individuals who have little or no residual vision and who have to rely predominantly on vision substitution skills, i.e. on using senses other than vision (Braille or talking books for reading, a long cane or guide dog for mobility, or touch for manipulation).

**Inclusions:** - visual impairment categories 4, 5, 6 in both eyes - visual impairment categories 4, 5, 6 in one eye [normal vision in other eye] - visual impairment categories 4, 5, 6 in one eye and categories 1, 2, 3 or 9 in the other eye - visual impairment category 5