Predictors for Retreatment Following Laser-Assisted in Situ Keratomileusis for High Myopia.

PURPOSE: To identify risk factors for retreatment after laser-assisted in situ keratomileusis (LASIK) in eyes with high myopia. SETTING: Care Vision Laser Center, Tel Aviv, Israel. DESIGN: Retrospective comparative study. METHODS: Data from eyes with myopia ≥ 6 D treated between 2000 and 2022 were analyzed. Eyes were grouped according to retreatment status. Preoperative and intraoperative parameters were compared using t tests and Chi-square tests. Generalized estimating equations (GEE) logistic regression accounting for inter-eye correlation, including variables with p<0.1, was performed to identify independent predictors of retreatment. RESULTS: The study included 2100 eyes (2020 controls and 80 retreatments). Retreatment eyes had shorter contact lens-free intervals (p=0.029) and a higher proportion of baseline cylinder <-1.0 D (32.5% vs 21.9%, p=0.025). Significant differences were observed in UCVA (p = 0.026) and BCVA (p=0.034). Intraoperatively, retreatment cases had higher treated cylinder (p=0.043), greater ablation depth (104.7±14.8 vs 100.6 ± 12.5 µm, p=0.004), and the optical-zone distribution differed between groups, with more 6.0-mm treatments and no 7.0-mm treatments in retreatment eyes (p<0.001). Retreatment was also associated with earlier surgical years (p<0.001) and use of the EX200 laser (p=0.01). GEE logistic regression identified two independent predictors: baseline cylinder < -1.0 D (OR 2.208, 95% CI 1.126-4.330, p=0.021) and EX200 laser use (OR 4.776, 95% CI 2.496-9.140, p<0.001). CONCLUSION: LASIK retreatment in high myopia is independently associated with higher baseline refractive cylinder and older laser technology (EX200). Optimizing patient selection and adopting modern laser platforms may reduce the likelihood of additional procedures.