Regression curves for the optical parameters of the eye

Based on the data collected by Stenstrom (1948), the regression curves involving refractive error and axial length are examined. The regression of refractive error on axial length is shown to be nonlinear; it curves upward at low axial lengths and downward at high axial lengths. It is shown that this curve can be partially accounted for by the lack of compensating corneal changes for extreme values of the axial length. On the other hand, the regression of axial length on refractive error, is shown to be approximately linear. The slope of this regression is related to a formula derived from geometrical optics.