Comparison of Femtosecond-assisted Laser In Situ Keratomileusis (FS-LASIK) and Keratorefractive Lenticule Extraction (KLEx) in Steep Keratometry

BACKGROUND: This study evaluates the impact of steep preoperative keratometry on postoperative refractive, visual, and higher-order aberration (HOA) outcomes in femtosecond-assisted laser in situ keratomileusis (FS-LASIK) and keratorefractive lenticule extraction (KLEx) procedures for moderate myopia and low astigmatism. PATIENTS AND METHODS: A retrospective analysis of 120 eyes from 120 patients who underwent FS-LASIK or KLEx between 2019 and 2023 was performed. Patients were divided into a steep keratometry group (Kmax 46 - 49 D) and a control group (Kmax 42 - 46 D). Uncorrected (UDVA) and corrected distance visual acuity (CDVA), spherical equivalent (SE), keratometry values, corneal thickness, and HOAs were assessed preoperatively and at six months postoperatively. RESULTS: Postoperative UDVA was lower in the KLEx group compared to FS-LASIK (p < 0.05). SE was more myopic in the KLEx group, probably due to differences in ablation profiles and corneal biomechanics. HOAs increased in all groups, with a significant rise in spherical aberration except in KLEx eyes with steep corneas. CONCLUSION: FS-LASIK and KLEx were effective and safe in eyes with steep preoperative keratometry. However, KLEx resulted in slightly more residual myopia, and postoperative HOAs varied by procedure and preoperative keratometry. Individualized surgical planning is essential, and further prospective studies are needed to assess long-term outcomes.