Abstract / Summary
Abstract PURPOSE To evaluate two-year changes in corneal and refractive astigmatism in myopic children wearing individualized ocular refraction customization (IORC) lenses with varying peripheral defocus, and associations with myopia progression. METHODS In year 1 of this trial, children aged 8–12 years were assigned to IORC lenses with high (4.50 D), medium (3.50 D), or low (2.50 D) peripheral myopic defocus, or single-vision lenses. After year 1, all switched to high-defocus IORC for 12 more months. Corneal and refractive astigmatism were converted to J0 and J45 vectors. Piecewise linear GEE models with a knot at 12 months estimated annualized changes per period, adjusting for age and sex. RESULTS Among 171 children completing 12 months and 161 completing 24 months, corneal J0 increased by 0.087 and 0.068 D/year in years 1 and 2; refractive J0 showed a similar pattern. Corneal J45 remained stable; refractive J45 showed a small negative drift. No significant group-by-time interactions were observed. By 24 months, vector displacement ≥ 0.25 D was 43.9% corneal and 42.2% refractive; ≥0.50 D was uncommon (4.7%, 3.4%). Refractive J0 change correlated with axial elongation at 24 months; corneal change showed only a weak association. CONCLUSION Over two years, IORC lenses did not induce clinically meaningful or dose-dependent astigmatic changes. The small with-the-rule J0 drift was consistent across groups and phases, suggesting a physiological origin, whereas J45 remained stable. The moderate association between refractive J0 change and axial elongation, without a corresponding corneal association, argues against lens-induced corneal remodeling. These findings support the optical safety of individualized IORC lenses in children.