Real-Life Orthokeratology for Myopia Control in Hungarian Children: A Five-Year Study of Axial Length Changes

Purpose: Orthokeratology is an established intervention for myopia control, but long-term European real-world data remain limited. This study evaluated 5-year axial length (AL) progression in Hungarian children undergoing orthokeratology and explored predictors of treatment response. Methods: This retrospective longitudinal study included 100 myopic children (198 eyes) treated with orthokeratology and followed for 5 years. AL was measured annually by optical biometry. By design, only children with uninterrupted follow-up on the same biometry device were included. Marginal multivariable regression with cluster-robust standard errors clustered on participant ID was used as the primary analytical approach; a linear mixed-effects model was applied as a sensitivity analysis. Responder analysis was performed using a biologically anchored threshold of <0.125 mm/year. Results: Mean cumulative AL elongation was 0.05 mm at 1 year and 0.34 mm at 5 years, corresponding to an annualised rate of 0.07 mm/year. First-year axial elongation was associated with 5-year AL change (r = 0.74, p < 0.001). Younger baseline age was the main predictor of greater AL progression, whereas baseline refractive status and sex showed no significant independent association with AL change. Responder rates were high, with 85.4% at eye level and 83.0% at the participant level. Conclusions: Orthokeratology was associated with low axial elongation over 5 years in this Hungarian paediatric cohort. These findings suggest favourable long-term axial length outcomes during orthokeratology treatment in routine clinical practice and underscore the importance of baseline age, whereas baseline refractive error did not show a significant independent association with treatment response.