EXCIMER-LASER TREATMENT OF MYOPIC ASTIGMATISM - A COMPARISON OF 3 ABLATION PROGRAMS

Objective: The purpose of the study was to evaluate the precision, acc uracy, and safety of three different modes of excimer laser surgery fo r myopic astigmatism. Design: A prospective interventional case series . Participants: A total of 150 eyes with compound myopic astigmatism w ere treated. Intervention: Ablation programs included the VISX Twenty/ Twenty excimer laser using either the sequential mode (58 eyes) or the elliptical mode (54 eyes) and the Technolas-Chiron Keracor 116 hybrid scanning laser (38 eyes). Main Outcome Measures: Reduction in cylinde r and sphere, vector analysis (polar values), uncorrected visual acuit y, and best spectacle-corrected visual acuity were evaluated at 1, 6, and 12 months. Results: By 12 months, sphere was reduced by 95.1%, 87. 7%, and 75% in low-astigmatism eyes treated with the VISX sequential, VISX elliptical, and Technolas modes, respectively, and by 92.2%, 98%, and 77.6% in high-astigmatism eyes. By 12 months, cylinder was reduce d by 51.5%, 72.2%, and 36.3% in low-astigmatism eyes and by 70%, 78%, and 45.6%, respectively, in high-astigmatism eyes. Vector analysis sho wed that the elliptical treatment produced more significant reductions in mean polar values than the other two treatments at various timepoi nts. Conclusion: These results suggest that the ablation approach may influence the clinical result.