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

Abstract

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.