Visual performance and reading capacity of partially sighted persons in a rehabilitation center.

Visual acuity and reading performance of 178 partially sighted patients from a rehabilitation center were measured using a TV text display device. A linear relation was demonstrated between visual acuity and reading speed for patients with visual acuity values below 15% of the normal value. With respect to reading performance, three groups of partially sighted patients could be distinguished: (1) 25% of the patients are unable to read visually and require tactile reading aids; (2) 50% are partially sighted and require high-magnification electronic reading aids; (3) 25% can read normal text by using optical magnifying devices. There is evidence that reading performance is related to the nature of the underlying ocular problem, such as refractive anomalies, macular degeneration, or other diseases.