Correlation between effective optical zone and higher-order aberrations in keratorefractive lenticule extraction and wavefront-guided laser in situ keratomileusis

This study aimed to analyze the correlations between the induction (Δ) of higher-order aberrations (HOAs) and the effective optical zone (EOZ) in keratorefractive lenticule extraction (KLEx) and wavefront-guided laser in situ keratomileusis (WG-LASIK), and to examine the effect of EOZ size on these correlations. This retrospective observational study included patients treated with KLEx and WG-LASIK for myopia or myopic astigmatism between 2018 and 2022. ΔHOAs and EOZ parameters were analyzed using Scheimpflug imaging at one month after surgery. Correlation analysis and multivariate linear regression between EOZ parameters and ΔHOAs were performed. A total of 271 eyes were included, of which 141 underwent KLEx and 130 underwent WG-LASIK. In eyes with smaller EOZ areas (≤ 24.9 mm²), EOZ decentration in KLEx showed positive correlations with Δcoma and Δvertical coma (correlation coefficient (ρ) = 0.551 and 0.524, respectively). EOZ decentration on the Y-axis in KLEx also correlated positively with Δvertical coma (ρ = 0.540), while in WG-LASIK, EOZ decentration on the X-axis correlated with Δcoma (ρ = 0.522) under similarly small EOZ areas. EOZ size parameters significantly contributed to Δspherical aberration in both procedures (p < 0.001). Conversely, these correlations were either not observed or significantly smaller in eyes with larger EOZ areas (> 24.9 mm²). In conclusion, maintaining a sufficiently large EOZ postoperatively is crucial. Moreover, precise surgical centration is vital for patients with smaller EOZ sizes, to reduce the induction of HOAs.