Comparison of 1-Year Clinical Outcomes Following SmartSight Lenticule Extraction Among Three Different Astigmatism Groups

Purpose: To compare the clinical outcomes of three different cohorts for astigmatism after keratorefractive lenticule extraction using the ATOS femtosecond laser system (Smart-Sight; SCHWIND eye-tech-solutions). Methods: In this retrospective, observational, non-randomized cohort study, 216 eyes from 129 patients treated consecutively with SmartSight lenticule extraction were retrospectively analyzed in three groups based on three different levels of astigmatism (low: 0.00 to −1.00 diopters [D]; moderate: −1.01 to −2.99 D; high: −3.00 to −5.25 D). Over all three groups, the patients' mean age was 27 ± 5 years (range: 18 to 39 years) and the mean preoperative spherical equivalent (SEQ) was −4.68 ± 1.94 D (range: −0.96 to −9.50 D), with a mean astigmatism of −1.87 ± 1.33 D (range: 0.00 to −5.12 D). At the 12-month follow-up visit, visual acuity, SEQ, cylinder, safety index, and efficacy index were analyzed individually for each group. All lenticule extraction treatments were performed using the SmartSight method with the SCHWIND ATOS femtosecond laser. Results: Mean residual astigmatism was −0.04 ± 0.12 D (range: 0.00 to −0.50 D), −0.06 ± 0.12 D (range: 0.00 to −0.50 D), and −0.09 ± 0.15 (range: 0.00 to −0.50 D), for the low, moderate, and high astigmatism groups, respectively. Postoperative astigmatism within ±0.25 D was achieved in 99%, 96%, and 94%, for the low, moderate, and high astigmatism groups, respectively ( P = .119). All eyes in each individual group were within ±0.50 D. The change in Snellen lines (comparing pre-operative CDVA to postoperative UDVA) showed a gain of one or more lines in 46% of the low astigmatism group, 63% of the moderate astigmatism group, and 32% of the high astigmatism group ( P < .001). Conclusions: The 12-month follow-up data show that SmartSight treatments for correction of myopia and myopic astigmatism with the SCHWIND ATOS is a safe, efficient, and accurate procedure irrespective of the level of preoperative astigmatism. However, a trend for refractive undercorrection was found for increasing astigmatism levels, partly reflected in the visual outcomes.