Gender differences in myopic regression, corneal haze, and ectasia after corneal refractive surgery: a retrospective cohort study

CLINICAL RELEVANCE: Understanding factors that influence refractive stability and postoperative complications after corneal refractive surgery is important for improving patient selection, risk assessment, postoperative management, and long-term visual outcomes. BACKGROUND: Gender-related differences in healing responses after corneal refractive surgery may influence rates of myopic regression and corneal haze, but evidence remains inconsistent. METHODS: This retrospective cohort study was conducted at a tertiary refractive surgery center of Harbin medical university and included patients undergoing LASIK, PRK, or SMILE. A total of 376 patients (752 eyes) with at least 12 months of follow-up were analysed. Myopic regression was defined as a ≥0.50 D myopic shift between 3- and 12-month postoperative refraction. Corneal haze was graded using the Fantes scale, and ectasia was diagnosed based on clinical and tomographic criteria. Multivariate logistic regression was performed to adjust for confounding variables. RESULTS: The cohort included 212 females (56.4%) and 164 males (43.6%) with a mean age of 28.9 ± 6.7 years. Baseline refractive and keratometric parameters were comparable between groups, although females had significantly thinner corneas. Myopic regression occurred in 18.2% of eyes and was significantly more frequent in females (20.5% vs. 15.3%, p = 0.048), with greater regression magnitude (-0.46 ± 0.33 D vs. -0.37 ± 0.29 D, p = 0.031). Corneal haze developed in 6.9% of eyes and was also more common in females (8.4% vs. 4.9%, p = 0.041), while persistent haze remained rare. Postoperative ectasia occurred in 0.53% of eyes with no sex-based difference (p = 0.62). Multivariate analysis identified younger age, higher preoperative myopia, PRK surgery, and high myopia as significant predictors of regression, whereas female sex was not independently associated (adjusted OR: 1.27, p = 0.174). . CONCLUSION: These findings suggest that clinical and surgical characteristics, rather than sex alone, should guide risk assessment and postoperative counselling.