Treatment of myopia and myopic astigmatism by customized laser in situ keratomileusis based on corneal topography

OBJECTIVE: To evaluate the predictability, efficacy, and safety of customized laser in situ keratomileusis (LASIK) based on corneal topography in myopia and myopic astigmatism. DESIGN: Prospective, noncomparative interventional case series. PARTICIPANTS: One hundred fourteen patients (eyes) with myopia of -1 to -6 diopters (D) and astigmatism of 0 to -4 D (low myopia group), and 89 patients (eyes) with myopia of -6.10 to -12.00 D and astigmatism of 0 to -4.00 D (high myopia group). INTERVENTION: LASIK was performed with the Hansatome Microkeratome and the Keracor 217 spot-scanning excimer laser (Bausch & Lomb Surgical Technolas, Munich, Germany). Individual ablation patterns were calculated on the basis of elevation data obtained with the Orbscan II corneal topography system (Bausch & Lomb Surgical, Irvine, CA). MAIN OUTCOME MEASURES: Manifest spectacle refraction, visual acuity, and change in visual acuity at 3 months after surgery. RESULTS: At 3 months, 51 patients in the low myopia group and 40 patients in the high myopia group were available. In the low (high) myopia group, 96.1% (75.0%) were within +/-0.50 D of emmetropia, and uncorrected visual acuity was 20/20 or better in 82.4% (62.5%), 20/25 or better in 98.0% (70.0%), and 20/40 or better in 100% (95.0%). A loss of two or more lines of spectacle-corrected visual acuity occurred in 3.9% of the low and 5. 0% of the high myopia group. In low myopia, spectacle-corrected visual acuity was 20/12.5 or better in 5.9% preoperatively and in 13.7% at 3 months and 20/15 or better in 37.3% and 47.1%, respectively. Differences were statistically significant. CONCLUSIONS: The customized LASIK based on corneal topography used in this study showed high predictability and efficacy in myopia and myopic astigmatism of -1.00 to -6.00 D, and could possibly improve spectacle-corrected visual acuity in myopia of -1.00 to -6.00 D. Predictability and efficacy were somewhat lower in myopia and myopic astigmatism of -6.10 to -12.00 D. In both groups, a small number of patients lost two or more lines of spectacle-corrected visual acuity.