Defocus incorporated multiple segment spectacle lenses versus orthokeratology lenses for myopia control: a non-inferiority randomised clinical trial.

BACKGROUND

To determine whether the Defocus Incorporated Multiple Segments (DIMS) spectacle lens is non-inferior to Orthokeratology lenses (OKL) in slowing the progression of myopia in children.

METHODS

A parallel-group, non-inferiority randomised clinical trial at the University Hospital of Southern Denmark compared the myopia control treatment efficacy of DIMS spectacle lenses with OKL in myopic children aged 6-12 years. Our primary outcome was axial length growth after 18 months of therapy, adjusted for change in central corneal thickness in the OKL group. The participants were allocated to the treatments using centralised computer-generated randomisation. The interpreters were blinded. Non-inferiority was concluded if the upper bound of the 95% confidence interval (95% CI) for the estimated treatment difference (DIMS - OKL) after 18 months was equal to or below 0.13 mm. In case of non-inferiority, superiority was tested in the same population. Superiority was declared if the upper 95%Cl bound was below zero. Our key secondary outcome was overall eye length growth after 18 months of therapy and was assessed for superiority.

RESULTS

90 participants were randomised to DIMS spectacle lenses (n = 45) and OKL (n = 45). For the primary outcome, 45 participants were analysed in both the DIMS spectacle lens and OKL groups using an intention-to-treat approach. A per-protocol approach was used for sensitivity analysis. The between-group difference (DIMS - OKL) in axial elongation was -0.05 mm (95% CI -0.13; 0.04) in a mixed model adjusted for covariates: age at baseline, baseline cycloplegic spherical equivalent refractive error, baseline axial length, and number of myopic parents, which is below the non-inferiority margin and above zero. The between-group difference (DIMS - OKL) in overall eye length elongation was -0.04 mm (95% CI -0.12; 0.04). One adverse event was observed in the OKL group.

CONCLUSIONS

The DIMS spectacle lens was noninferior to OKL for slowing axial elongation after 18 months of therapy in myopic children. The DIMS spectacle lens was not superior to OKL. There was no statistically significant difference in overall eye length growth between the DIMS spectacle lens and OKL after 18 months of therapy in myopic children.

TRIAL REGISTRATION: NCT05134935, 26 November 2021.