EXPERIMENTAL CORRECTION OF IRREGULAR CORNEAL ASTIGMATISM USING TOPOGRAPHY-BASED FLYING-SPOT-MODE EXCIMER-LASER PHOTOABLATION

PURPOSE: To present: a novel experimental approach for treating irregu lar corneal astigmatism, METHODS: After decomposition of topographic a nalysis data into orthogonal Zernike polynomials, a regular target sur face was defined, and the abla tion profile was calculated. In a polym ethylmethacrylate with an irregular surface, computer-controlled ablat ion was performed using a 193-nm excimer laser in ''flying-spot mode.' ' RESULTS: The difference between flattest and steepest. hemimeridians in the 3-mm zone, surface regularity index, and surface asymmetry ind ex were reduced from 8.7 to 1.1 diopters, 1.19 to 0.39, and 1.84 to 0. 14, respectively. CONCLUSION: Tying corneal topography into laser soft ware offers a straightforward concept for correction of irregular corn eal astigmatism in an experimental model.