Increased axial elongation and myopia risk in non-myopic adolescents with convergence insufficiency

Background/Objectives: To investigate the association between convergence insufficiency (CI) and ocular biometric changes indicative of future myopia development in a non-myopic adolescent population. Subjects/Methods: This one-year longitudinal study enrolled 244 non-myopic male adolescents (aged 14–17), comprising 50 with CI and 194 normal controls. Comprehensive visual function and ocular biometry assessments were conducted at baseline, 3, 9, and 12 months. Results At baseline, the CI group exhibited significantly poorer binocular function, including reduced negative relative accommodation (NRA) ( p  = 0.02), convergence amplitude ( p  = 0.00), and Accommodative Convergence / Accommodation (AC/A) ratio ( p  = 0.00), along with a deeper anterior chamber depth (ACD) ( p  = 0.01) and larger white-to-white (WTW) distance ( p  = 0.00) compared to normal controls. After 12 months, axial elongation was significantly greater in the CI group (0.16 ± 0.12 mm vs. 0.11 ± 0.16 mm, p  = 0.02). A higher proportion of participants in the CI group experienced clinically significant axial elongation (≥ 0.2 mm) (34.0% vs. 19.1%, p  = 0.02). Conclusion CI is associated with accelerated axial elongation and distinct ocular biometric profiles in non-myopic adolescents, suggesting it may be an early functional risk factor for myopia onset.