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

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).

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.

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).

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.