Effect of Total Laser Fluence on Early and Mid-term Visual and Optical Quality Outcomes After Lenticule Extraction With the SCHWIND ATOS: A Single-Center Study

Purpose: To evaluate the effect of total laser fluence on early and mid-term visual outcomes after keratorefractive lenticule extraction performed with a femtosecond laser. The setting was a single-surgeon, single-center refractive surgery clinic. The design was a retrospective comparative cohort analysis of prospectively collected data. Methods: This retrospective comparative case series included 112 eyes of 112 patients. Eyes were stratified into four quartiles (Q1 to Q4, n = 28 each) based on total fluence (range: 290 to 767 mJ/cm 2 ). Outcomes included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest spherical equivalent, and higher order aberrations (HOAs) measured by corneal and ocular wavefront at 4 and 6 mm. Assessments were performed at postoperative day 1 (POD1) and month 6 (POM6). Statistical analyses used Kruskal–Wallis and Mann–Whitney U tests with Holm step-down correction. Results: At POD1, lower fluence groups showed faster UDVA recovery (Q1: −0.11 ± 0.07 vs Q4: −0.01 ± 0.10 logMAR), but these differences were not significant after Holm correction. By POM6, UDVA was excellent across all quartiles. CDVA line gains were significantly more frequent in Q1 and Q2 (79% and 54% gained ⩾ one line) compared with Q3 and Q4 (7% each, Holm-adjusted P < .005). Predictability remained high, with 82% to 93% of eyes within ±0.50 diopters at 6 months. HOA induction was slightly greater with higher fluence at POD1 but converged by POM6, except spherical aberration at 6 mm, which differed significantly ( P = .006). Conclusions: Lower total fluence was associated with non-significant trends toward faster recovery and greater mid-term CDVA gains, whereas refractive accuracy and safety were not compromised. Fluence optimization may enhance early visual quality without sacrificing predictability.