Blindness Definitions and Statistics

Blindness is typically defined by visual acuity (sharpness) or field of view. Legally, severe vision impairment is a best-corrected visual acuity of 20/200 or worse in the better eye or a visual field of 20 degrees or less. Globally, an estimated 2.2 billion people have some level of vision impairment, with about 36 million classified as blind. Causes vary and include age-related conditions, diseases, and injury. Access to eye care and treatment can significantly reduce blindness, but disparities remain across regions and populations. These statistics highlight the importance of eye health and preventive care worldwide.