Blind

A visual impairment severe enough that a person cannot use vision as their primary means of perceiving information, typically defined legally in the United States as best-corrected visual acuity of 20/200 or worse in the better eye, or a visual field of 20 degrees or less. Blindness spans a spectrum from total blindness (no light perception) through light perception only to low useful vision, and people who are blind use assistive technologies such as screen readers, refreshable Braille displays, tactile graphics, and navigation aids. In accessibility research the acronym BVI (blind and visually impaired) is often used to refer to the broader population inclusive of low-vision users.