Refractive error distribution in a profoundly retarded population.

The refractive errors distribution of 103 profoundly retarded individuals (10 of zero to 20) was determined. This distribution was skewed in the direction of myopia. Since no such data were available for any other profoundly retarded population, direct comparison with other studies was not possible. However, a significant difference in mean spherical equivalent was found between the profoundly retarded of this study and the combined severely and profoundly retarded of two earlier studies.