Association of Treatment Decentration with Early Outcomes Following SMILE Pro: A Secondary Analysis

Abstract

Purpose To evaluate the association of system-recorded treatment decentration with 3-month visual, refractive, and higher-order aberration (HOA) outcomes after SMILE Pro (VisuMax 800 femtosecond laser). Patients and Methods This secondary exploratory analysis of prospectively collected data included 186 eyes of 94 consecutive patients. Treatment decentration—the system-recorded scalar distance between the corneal vertex and the achieved lenticule center—was categorized as <0.10 mm (n = 94), 0.10–0.20 mm (n = 73), or ≥0.20 mm (n = 19). Primary outcomes were 3-month uncorrected distance visual acuity (UDVA), residual spherical equivalent (SE), and anterior corneal wavefront HOA (6-mm pupil) with its change from baseline (ΔHOA). Generalized estimating equations (GEE) clustered by patient constituted the primary analysis; rank-based tests were secondary. Results Median decentration was 0.098 mm (IQR 0.067–0.150 mm; maximum 0.345 mm). At 3 months, 98.4% of eyes achieved UDVA ≥20/20, 96.2% were within ±0.50 D of target, and no eye lost corrected distance visual acuity. UDVA, residual SE, and postoperative HOA were not significantly associated with decentration group (all GEE Wald P > 0.26). ΔHOA was greater in the 0.10–0.20 mm group than in the <0.10 mm group (GEE β = +0.048 μm, 95% CI 0.013–0.082, P = 0.007), whereas rank-based tests were marginal (Kruskal–Wallis P = 0.065), the ≥0.20 mm group did not differ, and the continuous Spearman correlation was not significant (ρ = 0.116, P = 0.114). Conclusion Within the narrow decentration range achieved with CentraLign-guided SMILE Pro, decentration magnitude was not associated with 3-month visual or refractive outcomes. Smaller higher-order aberration induction was associated with decentration below 0.10 mm than with decentration of 0.10 to <0.20 mm; this association was not observed in the ≥0.20 mm stratum.