Astigmatism among institutionalized and noninstitutionalized mentally retarded.

Astigmatism was measured retinoscopically for 709 subjects residing in an institution for the mentally retarded and for 56 noninstitutionalized mentally retarded subjects at a community training center. About 60% of the subjects were between 15 and 45 years old. Compared to an intellectually normal sample of young men, astigmatism in the mentally retarded was greater in frequency and degree. For subjects with greater degrees of mental retardation, the prevalence of high astigmastism was significantly greater for whites than for nonwhites. There was no difference in astigmatism between institutionalized retardates and those living in a community setting, a finding that implies that the institutional environment was not the cause of the astigmatic differences between retarded and normal subjects.