Vector analysis of myopic astigmatism corrected by femtosecond refractive lenticule extraction

Purpose To evaluate the visual outcome of refractive lenticule extraction in eyes with myopic astigmatism using the Visumax femtosecond laser. Setting Department of Ophthalmology, HELIOS Klinikum Erfurt, Erfurt, Germany. Design Nonrandomized clinical trials. Methods The data set encompassed treatments of sphere and astigmatism. Vector analysis was performed to study the astigmatic results at each follow-up visit at 1 week and 1, 3, and 6 months. Visual outcomes were analyzed for the 6-month follow-up period. Results The data evaluated was a complete set of refractive data of 182 treatments (87 left eyes, 95 right eyes). Efficacy, predictability, and safety with regard to astigmatic correction were comparable to the results with U.S. Food and Drug Administration–approved excimer lasers. At 6 months, the mean error ratio was 0.68 ± 0.75 (SD) and the mean correction ratio was 1.11 ± 0.69. There was slight astigmatic undercorrection (approximately 10%) over time. The residuum of the linear regression analysis of the predictability plot was approximately 0.4 diopter. Ninety-six percent of the eyes had a corrected distance visual acuity (CDVA) of 20/20 or better; no eye had a CDVA worse than 20/32. Conclusion Femtosecond refractive lenticule extraction is an effective procedure for correcting myopic astigmatism. Financial Disclosure Drs. Sluyterman v. L. and Russmann are employees of and Drs. Blum and Kunert are investigators for Carl Zeiss Meditec AG, Jena, Germany.