Corneal tissue mass in normal and keratoconic eyes. In vivo estimation based on area of horizontal optical sections

Based on measurements of the corneal diameter, radius of curvature variation, and thickness profile a method for calculation of the horizontal meridian's sectional tissue mass area (M) is described. Pooled values of 52 normal eyes demonstrate M to be 8.57 mm2 +/- SD. Comparing one eye of 27 keratoconic patients with one eye of 28 normals established no significant difference in M. This result is in accordance with a hypothesis in which the keratoconic corneal thinning is a result of an increased sliding of collagen fibers rather than a result of increased collagen degradation.