Peripheral refraction and myopia progression after 36 months of orthokeratology wear in schoolchildren

Background: Orthokeratology (Ortho-K) effectively slows axial elongation in myopic eyes, but its long-term effects on peripheral refraction (PR) and its relationship with myopia progression remains unclear. Aim: This study aimed to determine the changes in PR and myopia progression over 36 months of Ortho-K wear in children. Setting: This is a prospective cohort study. Methods: Twenty-nine myopic children aged 8–9 years old were enrolled in this study. Ortho-K lenses were prescribed, and analyses were conducted at baseline, 12, and 36 months (M). Assessments included axial length (AL) and cycloplegic refraction at central and peripheral (30°N, 20°N, 10°N, 10°T, 20°T, and 30°T). Intraocular pressure (IOP), corneal thickness and endothelial morphology were monitored throughout the study. Data were analysed using repeated-measures ANOVA or the Friedman test, with Bonferroni correction; p < 0.05 was considered significant. Results: Relative peripheral refraction (RPR) shifted from baseline hyperopic to myopic defocus at 12M at 30°N, 20°N, 20°T, and 30°T (p < 0.01). A further significant myopic shift was observed at 20°N after 12M, but no correlation with AL growth. Axial length decreased significantly in the first year (−0.16 ± 0.04 mm, p = 0.003), then elongated slowly thereafter (0.24 ± 0.08 mm in the next 24M, p = 0.02). Best corrected visual acuity remained stable, and no significant changes in ocular health parameters or complications were observed. Conclusion: Wearing Ortho-K lenses for 36 months slowed down axial elongation and sustained peripheral myopic defocus without compromising ocular health. Regular IOP and corneal health monitoring are recommended to ensure stable ocular physiology during long-term Ortho-K wear. Contribution: This study provides evidence on the effectiveness and ocular physiological responses of long-term wearing of Ortho-K lenses in children.