Refractive and axial changes in Korean children with myopia and their association with uncorrected visual acuity

Abstract Purpose To examine the relationship between annual spherical equivalent (SE) change and axial length (AL) change and compare their exploratory discrimination of an uncorrected visual acuity (UCVA) endpoint in Korean children with myopia. Methods A single-centre observational cohort included 280 children aged 6–12 years with myopia who were followed for 24 months. Cycloplegic refraction, AL and visual acuity were assessed at 6-month intervals. The UCVA endpoint was logMAR ≥ 0.3 at a follow-up visit. Receiver operating characteristic areas under the curve (AUCs) were compared using the DeLong test. Analyses were interpreted as within-cohort discrimination rather than prospective prediction. A composite of annual SE change ≤ − 0.50 D/year or AL elongation ≥ 0.20 mm/year was used only for descriptive grouping. Results The mean age was 8.4 years (SD 1.6); 147 participants (52.5%) were girls. The descriptive progression criterion was met by 192 children (68.6%). For the UCVA endpoint, reported AUCs were 0.90 (95% confidence interval [CI] 0.86–0.94) for SE and 0.85 (95% CI 0.80–0.90) for AL (DeLong p = 0.031). The combined SE–AL model had an apparent AUC of 0.98 (95% CI 0.96–0.99). Annual SE and AL changes were inversely associated, with a reported slope of − 1.93 D/mm and R² of 0.61. Conclusion SE change showed greater within-cohort discrimination of the UCVA endpoint than AL change, and the combined model had a higher apparent AUC. These findings support further evaluation of joint SE and AL assessment. Prospective predictive performance and the clinical value of the candidate thresholds require validation.