Definition: Visual impairments limiting one or more of the basic functions of the eye: visual acuity, dark adaptation, color vision, or peripheral vision. These may result from EYE DISEASES; OPTIC NERVE DISEASES; VISUAL PATHWAY diseases; OCCIPITAL LOBE diseases; OCULAR MOTILITY DISORDERS; and other conditions. Visual disability refers to inability of the individual to perform specific visual tasks, such as reading, writing, orientation, or traveling unaided. (From Newell, Ophthalmology: Principles and Concepts, 7th ed, p132)