Axial changes and long-term myopia progression with orthokeratology: A risk-stratification study

PURPOSE: To analyze long-term changes in axial length and anterior segment parameters among children wearing orthokeratology lenses and screen indicators correlated with 5-year myopia progression risk. METHODS: A retrospective study enrolled 61 children with 5-year follow-up after orthokeratology lens fitting. Participants were stratified into a slow progression group (n = 32, 5-year axial length elongation ΔAL₅ < 1 mm) and a rapid progression group (n = 29, ΔAL₅ ≥ 1 mm). The axial length, lens thickness, anterior chamber depth, and central corneal thickness were monitored from baseline to 5 years. Correlation analysis, ROC curve analysis, multivariate binary logistic regression, and repeated-measures ANCOVA were performed for statistical analysis. RESULTS: Baseline age was the only parameter that showed significant intergroup differences (P < 0.001). ΔAL₁ to ΔAL₄ were positively correlated with ΔAL₅ (all P < 0.001). ΔAL₁ yielded an AUC of 0.860 (95% CI: 0.761-0.960) with an optimal cutoff of 0.155 mm, and ΔAL₃ achieved an AUC of 0.907 (95% CI: 0.829-0.984) with an optimal cutoff of 0.480 mm. ΔLT₃ to ΔLT₄ were negatively correlated with ΔAL₅ (P < 0.05, AUC = 0.704). Significant time-group interactive effects were detected in axial length, anterior chamber depth, lens thickness, and central corneal thickness (all P < 0.05). CONCLUSIONS: Early and mid-term axial length variations are strongly associated with long-term myopia progression under orthokeratology intervention. Axial elongation exceeding 0.480 mm at year 3 indicates a high risk of rapid myopia progression, and 1-year axial growth exceeding 0.155 mm facilitates early risk stratification.