Abstract
BACKGROUND: Myopia has emerged as a significant public health concern in China. Despite age and axial length-to-corneal radius ratio (AL/CR) being widely recognized as independent factors influencing myopia in children and adolescents, very few studies have investigated the combined effects of these two factors or the extent of their interaction. This cross-sectional study aimed to examine the association and interaction between age and AL/CR and the prevalence of myopia in children and adolescents, providing evidence for early myopia prevention and control. METHODS: In 2022, three primary schools in Shenzhen were selected via random cluster sampling. Students who had lived in Shenzhen for over 6 months were administered surveys, and underwent myopia screenings (visual acuity and noncycloplegic autorefraction) and ocular biometric measurements. Logistic regression analysis was performed to assess the interaction between age and AL/CR using both multiplicative and additive models. A generalized additive model was used to evaluate the relationship among age, AL/CR, and myopia prevalence, with the results presented through visualization analysis. RESULTS: A total of 3,220 participants were included (mean age of 8.95 ± 1.77 years; mean AL/CR ratio of 3.01 ± 0.13). The overall prevalence of myopia was 47.67%. After adjusting for sex, parental myopia, reading and writing posture, per capita monthly income, and anterior chamber depth, a significant multiplicative interaction between age and AL/CR on myopia prevalence (OR = 2.147, 95% CI 1.553-2.968) was observed. Additive interaction analysis further revealed a relative excess risk due to interaction of 10.816 (95% CI 8.027-13.605), an attributable proportion of 0.700 (95% CI 0.636-0.763), and a synergy index of 3.971 (95% CI 3.065-5.143). CONCLUSION: The interaction between age and AL/CR was associated with a greater likelihood of myopia, with both positive multiplicative and additive effects observed. Older age and increased AL/CR ratios were associated with a greater likelihood of myopia in children and adolescents, emphasizing the importance of early prevention strategies.