Visual impairment is loss of visual acuity, visual field, or both as a result of defect, disease, or injury to the organs of vision (eye, optic nerve, visual tract, and brain). Even with correction, ability to see is significantly below the level that allows normal visual access to information and the environment. The extent to which a visual impairment produces disability varies with the degree of vision loss, age of onset, ability to use other senses to supplement or substitute for vision, absence or presence of other disabilities, and diagnosis-prognosis.
A wide variety of impairments to sight, including but going far wider than legal blindness.