Genetic analysis of indices of corneal power and corneal astigmatism in human populations with varying incidences of strabismus.

Heritability estimates for corneal power were found to be high and similar for two populations which differed in their incidence of esotropia. This similarity suggest (1) that genetic differences for corneal power do not contribute to the difference in heritability for spherical refractive error reported for these populations and (2) that this character is not a critical variable contributing to the pathophysiology of esotropia. Heritability estimates for corneal astigmatism were, in most cases, rather low. The pattern of population and sex differences among heritability estimates was consistent with those previously reported for cylindrical refractive error. These population differences in heritability suggest that they contribute to population differences found for cylindrical refractive error.