Changes in Corneal Epithelial Thickness in Different Areas After Femtosecond Laser–Assisted LASIK in Patients With High Astigmatism

Abstract

Purpose: To explore changes in corneal epithelial thickness (CET) after femtosecond laser–assisted laser in situ keratomileusis in patients with high astigmatism. Methods: CET was measured at every intersection of the concentric circles and specific axes using AngioVue optical coherence tomography (Angio-OCT) preoperatively and 1 month postoperatively. The average thickness of corneal central, paracentral, and peripheral regions was the mean of the points within the central 2, 2 to 5, and 5 to 7 mm areas, respectively. Correlation analysis was performed to investigate the association between CET along different axes and other preoperative and postoperative parameters. Results: Forty-two eyes of 28 patients were included. CET along the astigmatic (K1) and perpendicular (K2) axes in the central and paracentral areas increased ( P < .001), whereas that along the K2 axis decreased in the peripheral area 1 month postoperatively ( P = .001). The amount of CET change in the peripheral area between the K1 and K2 axes was significantly different ( P < .001). In the central area, the change in CET along the K2 axis was positively correlated with ablation depth ( r = 0.315, P = .042) and negatively with refractive power after surgery ( r = −0.347, P = .024). In the peripheral area, the changes in CET along both K1 and K2 axes were negatively correlated with ablation depth ( r = −0.431, P = .004; r = −0.387, P = .011, respectively). Conclusions: Epithelial modeling differed between the different astigmatism axes after refractive surgery. The compensatory response of the corneal epithelium is more pronounced along the steeper axis. [ J Refract Surg . 2024;40(4):e239–e244.]