Assessment of an elastic model in the pathogenesis of keratoconus

One eye of 27 patients with keratoconus and 37 normals were examined by photokeratoscopy and topographic pachometry to obtain comparative informations about the corneal shape and thickness profile, characterized by radius of the central curvature K, the coefficient of radius variation RV, the central corneal thickness T and the coefficient of thickness variation TV. RV and TV express the corneal central-peripheral variation in radius of curvature and thickness, respectively. Compared with normals the keratoconic corneas demonstrate a decrease in K and T and an increase in RV and TV. In the keratoconic eyes the decrease in K is positively correlated to the decrease in T. Further the decrease in K and T are both negatively correlated to the increase in RV and TV. Finally the increase in RV is positively correlated to the increase in TV. The results are in good accordance with an elastic model which implies increased distensibility of the keratoconic corneal tissue as a pathogenetic factor in the development of keratoconus.