Steiger on refraction: a reappraisal.

Seventy years ago Steiger, a Swiss ophthalmologist, found the distribution of corneal powers to follow a normal (binomial) curve. He noted a wide range of values among emmetropes, and he also knew that their axial lengths varied significantly. He expected that normal distributions would be found for other components of refraction and also for refraction as a whole, and in seeking a controlling mechanism he recalled the multifactorial pattern of inheritance of such characteristics as stature. The present study employs modern mathematical techniques to test the validity of 2 related hypotheses: that the components of refraction are correlated and that a polygenic mode of inheritance is responsible for determining the refractive power of the eye. In the light of this study and of other modern knowledge about refraction Steiger's work is reassessed. Most of his views are vindicated, although his assumption of a normal distribution for refraction as a whole could not be justified. His contribution to the understanding of refraction establishes him among the great names in ophthalmology.