Preoperative and postoperative risk factors for persistent dry eye after corneal refractive surgery in ultra-high myopia: a retrospective cohort study.

OBJECTIVE: To identify risk factors for persistent dry eye after refractive surgery in patients with ultra-high myopia and their prognostic value. METHODS: Data from 260 patients were analyzed. Least absolute shrinkage and selection operator regression screened preoperative variables. Random forest, Extreme Gradient Boosting, multivariate logistic regression, mediation, and interaction analyses were used to identify predictors and mechanisms of persistent dry eye (≥ 3 months). RESULTS: Persistent dry eye occurred in 33.1% of patients (86/260). Eight preoperative predictors were identified. Elevated Ocular Surface Disease Index (OSDI) (odds ratio [OR] = 1.483) and corneal fluorescein staining (CFS) (OR = 7.154) were independent risk factors; prolonged tear film breakup time (TBUT) (OR = 0.292), no systemic history (OR = 0.042), and normal meibomian gland dysfunction (MGD) (OR = 0.042) were protective. Age and Schirmer test were marginally significant. Medication adherence fully mediated the effect of age on dry eye duration, while ocular inflammation partly mediated the effect of photorefractive keratectomy surgery. A significant synergistic interaction was found between postoperative inflammation and medication adherence (P < 0.05). CONCLUSION: Persistent dry eye after refractive surgery for ultra-high myopia is influenced by multiple factors. Preoperative OSDI, CFS, TBUT, systemic history, MGD, daily screen time, medication adherence, and inflammation play important roles. Individualized perioperative management targeting these factors may improve prognosis.