Association between intraoperative decentration and corneal higher-order aberrations in lenticule extraction surgery.

BACKGROUND

Precise centration during refractive lenticule extraction is critical for optimal visual outcomes. However, intraoperative decentration between the corneal vertex (CV) and the lenticule center (LC) may occur, and its impact on postoperative corneal higher-order aberrations (HOAs) remains incompletely understood.

METHODS

This retrospective observational study analyzed surgical videos of 331 SmartSight procedures performed at Cheongju First Eye Clinic, Cheongju, South Korea. Intraoperative decentration was measured as the distance between the preoperative CV (obtained from Scheimpflug tomography) and the intraoperative LC. A piecewise linear regression identified a slope change at 232 μm, which defined Group I (≤ 232 μm) and Group II (> 232 μm). Corneal HOAs—including total HOA, coma, trefoil, and spherical aberration (SA)—were measured preoperatively and at 1 and 3 months postoperatively within a 6 mm analysis zone. HOA changes were compared between groups.

RESULTS

Mean decentration was 180 ± 96 μm. At 1 month, total HOAs increased by 0.05 ± 0.15 μm in Group I and 0.09 ± 0.21 μm in Group II; coma increased by 0.05 ± 0.14 μm vs. 0.09 ± 0.17 μm, respectively (p < 0.05). At 3 months, total HOAs (0.07 ± 0.17 μm vs. 0.18 ± 0.28 μm), coma (0.06 ± 0.14 μm vs. 0.15 ± 0.20 μm), and SA (0.01 ± 0.12 μm vs. 0.06 ± 0.17 μm) were significantly greater in Group II (p < 0.05). Trefoil changes were not significant. Preoperative pupillary offset showed no significant correlation with decentration or HOA change.

CONCLUSIONS

Greater intraoperative decentration is associated with increased induction of corneal HOAs. Precise centration is essential in SmartSight surgery to minimize optical aberrations.