Meridional variations of corneal shape

The corneal shape of 196 eyes was determined by photokeratoscopy and subsequent fitting of a conicoid equation to four individual corneal meridians. This conicoid was found in almost all instances to be ellipsoidal, with the asphericity not varying between meridians. The corneal radius of curvature did vary as expected between meridians. The radii of curvature of these corneal meridians also varied with the age of the subjects, resulting in reduced corneal astigmatism, while the asphericity of each meridian did not vary substantially with age.