Intraoperative docking offset and postoperative coma with and without automated offset compensation after KLEx

Keratorefractive lenticule extraction (KLEx) lacks active eye tracking, making intraoperative decentration a potential source of postoperative higher-order aberrations (HOAs). This study evaluated the clinical impact of an automated centration compensation system on visual quality after KLEx. This retrospective study included 196 eyes (98 patients) undergoing KLEx, divided into a non-compensated group (NCG, 104 eyes) and a compensated group (CG, 92 eyes) treated using automated centration software. The pupil–guideline offset during docking (docking offset) was quantified from intraoperative screenshots as a surrogate for decentration. Visual and refractive outcomes and corneal HOAs (6-mm zone) were evaluated preoperatively and at 1 and 3 months postoperatively. Linear mixed-effects models, linear regression, and quantile regression analyses were performed. Mean intraoperative docking offset did not differ between the groups ( p = 0.451). UDVA, refractive outcomes, and mean higher-order aberrations did not differ significantly between the groups at either timepoint. In the NCG, a greater docking offset was significantly associated with a larger increase in coma at 1 and 3 months, whereas this association was absent in the CG; the group × docking offset interaction, however, was not significant ( p = 0.051 and p = 0.272). Quantile regression showed a smaller increase in coma in the CG at the higher quantiles at 1 month (75th percentile, p = 0.006; 90th percentile, p = 0.014), with no difference at 3 months. Coma outliers were numerically fewer in the CG at both timepoints, but not significantly so. Automated centration compensation during KLEx was associated with smaller increases in corneal coma at the upper quantiles at 1 month, although mean aberrations did not differ significantly between groups and the between-group difference in docking offset–coma slopes was not statistically established.