A COMBINED INCISION TECHNIQUE OF RADIAL KERATOTOMY - A COMPARISON TO CENTRIPETAL AND CENTRIFUGAL INCISION TECHNIQUES IN HUMAN DONOR EYES

Purpose: To evaluate and compare the extent of corneal flattening and the anatomy of the incision grooves produced by centrifugal, centripetal, and combined incisions in a human donor eye model. Methods: Twenty-seven eyes, divided into three groups of nine, received eight-incision radial keratotomy using the centrifugal, centripetal, or combined incision technique. Corneal curvature was evaluated using a topography system, and the anatomy of the incision was assessed by light microscopy and scanning electron microscopy. Results: The average central corneal flattening at the 3-mm clear zone was 4.16 +/- 1.47 diopters (D) for centrifugal incisions; 7.71 +/- 2.77 D for centripetal incisions; and 9.26 +/- 1.75 D for combined incisions. The difference in corneal flattening between eyes that received centrifugal versus either centripetal or combined incisions was significant (P < 0.01), whereas the difference between combined and centripetal incisions was not significant (P = 0.174). Anatomic differences were observed within the incision grooves produced by the three techniques. Conclusion: The authors describe a novel combined incision technique of radial keratotomy that provides the potential safety of a centrifugal incision with the effect of a centripetal incision.