Corneal topography in myopic patients undergoing epikeratophakia

We analyzed the corneal topography of eight eyes in seven patients who had undergone myopic epikeratophakia, using a 1.5-mm graft/host disparity. Topographic maps of corneal power generated by computer analysis of keratoscope photographs disclosed a central spherical optical zone smaller in diameter than was predicted by the preoperative lathing measurements. Outside this optical zone, the dioptric power of the graft surface increased steadily, indicating a progressive steepening of the corneal slope as the graft/host interface is approached. This pattern occurred in patients with accurate and inaccurate refractive results. The center of the graft was noted in some cases to be decentered from the patient's visual axis. The corneal topography analysis system has made clear the need to maximize the diameter of the effective optical zone.