Trapezoidal Astigmatic Keratotomy in Human Cadaver Eyes

Abstract

Twenty human cadaver eyes underwent partial depth corneal incisions under an operating microscope equipped with a Terry keratometer. A pattern of radial and tangential incisions originated by Dr. Luis Ruiz were made with a diamond knife at 3.0, 4.0, 5.0, and 6.0 mm optical zones. Keratometric readings were taken at various stages of the operation to better understand the dynamics of the technique. Tangential incisions were found to have different effects on the central corneal curvature at different optical zone sizes. The change in keratometric readings induced by the completed astigmatic keratotomy was measured at different optical zone sizes. A linear regression of the total change in diopters by keratometry to the size of the optical zone revealed a downward slope significant to the p<.001 level.