Transient Endothelial Damage Following FS-LASIK Combined With Corneal Cross-Linking Surgery: Case Report

BACKGROUND Refractive surgery in high myopia with thinner corneas and borderline topography is challenging, with the most serious complication being regression and postoperative ectasia. We report early corneal endothelial damage in a patient with high myopia after undergoing femtosecond laser-assisted in situ keratomileusis (FS-LASIK) with corneal cross-linking. CASE REPORT This article reports an observational case of an 18-year-old man with high myopia who underwent FS-LASIK combined with corneal cross-linking. FS-LASIK was performed using a Zeiss femtosecond laser for flap creation (90 µm right eye, 95 µm left eye) and a EX500 excimer laser for corneal ablation (130 µm right eye, 131 µm left eye). Accelerated cross-linking was conducted with 0.23% riboflavin infiltration beneath the corneal stromal flap for 90 seconds, followed by UVA irradiation at 30 mW/cm² for 90 seconds (total energy dose, 2.7 J/cm²). On postoperative day 3, slit-lamp examination revealed corneal edema in the right eye and hyporeflective endothelial changes in both eyes. Endothelial microscopy showed significant reductions in endothelial cell density and hexagonal cell percentage compared with preoperative values. By 1 week postoperatively, the corneal edema and endothelial morphological irregularities had resolved, and the number and area of hyporeflective endothelial defects were markedly reduced. At 2 months postoperatively, visual acuity of both eyes was 20/20, hyporeflective zones on the endothelial surface disappeared, and corneal endothelial cell count, percentage of hexagonal cells, and coefficient of variation in cell size returned to preoperative levels. CONCLUSIONS This case highlights early, reversible endothelial damage following FS-LASIK with corneal cross-linking, underscoring the importance of careful patient selection, detailed preoperative counseling, and strong consideration of alternative treatments.