Axial length changes during short-term orthokeratology discontinuation for lens replacement in children.

PURPOSE: Routine orthokeratology (Ortho-K) lens replacement often requires short-term treatment disruption, which may lead to an increase in axial elongation. This study aimed toevaluate axial length (AL) alterations during short-term Ortho-K discontinuation for routine lens replacement in long-term paediatric wearers and examined if adjunctive low-dose atropine mitigates this axial elongation.

METHODS

This retrospective cohort study included 126 children with myopia undergoing routine Ortho-K lens replacement at approximately 2-year intervals. AL was measured at the time of lens discontinuation and 1 week after Ortho-K wear resumption. Participants were classified into atropine-bridge (AB) or non-bridge (NB) groups based on the use of 0.01% atropine during discontinuation. Changes in AL across replacement cycles were analysed, and generalised estimating equation models were used to identify factors associated with axial elongation while considering repeated measures.

RESULTS

The AL increased significantly during the first discontinuation period (mean 0.039 ± 0.078 mm, p < 0.001); AL did not change significantly during the subsequent replacement cycles. At initial interruption, axial elongation magnitude exceeded the average monthly AL growth during active Ortho-K wear and age-matched normative data. Furthermore, AL change did not significantly differ between the AB and NB groups. In multivariable analyses, longer cumulative Ortho-K wearing duration was associated with less axial elongation during short- term Ortho-K discontinuation, whereas age, sex, baseline refractive status, baseline AL, and atropine use were not significant predictors.

CONCLUSIONS

Short-term Ortho-K discontinuation for initial lens replacement is associated with a transient increase in axial elongation that diminishes with longer cumulative lens wear. Furthermore, short-term bridging with 0.01% atropine did not provide a clear additional protective effect. Maintaining continuity of effective Ortho-K treatment and minimising unnecessary interruption, specifically during early replacement cycles, is crucial to optimise long-term myopia control.