Adult myopia progression in high myopes aged 18–25 years: evidence from a population-based cohort

Aims To investigate the prevalence and severity of adult myopia progression among highly myopic individuals aged 18–25 years, identify its associated factors and evaluate its association with pathologic myopia (PM). Methods We retrospectively included participants aged 18–25 years with consecutive follow-ups from the Shanghai Child and Adolescent Large-scale Eye Study database. Annual changes of cycloplegic spherical equivalent (ΔSE) and axial length (ΔAL) were calculated. Adult myopia progression is defined as ΔSE ≤−0.50 D/year or ΔAL≥0.10 mm/year. PM was diagnosed based on META-Analysis for Pathologic Myopia criteria (category≥2) and optical coherence tomography (OCT) images. Results Among all included 345 eyes, the mean ΔSE was −0.28 D/year (95% CI −0.31 to −0.20; p<0.001) and 64 (18.6%) were classified as having adult myopia progression. The mean ΔAL was 0.09 mm/year (95% CI 0.09 to 0.10; p<0.001), with axial elongation observed in 138 (40.0%) eyes. Both age (ΔSE: β=0.045, p=0.005; ΔAL: β=−0.015, p<0.001) and baseline AL (ΔSE: β=−0.044, p=0.028; ΔAL: β=0.020, p<0.001) were identified as factors associated with ΔSE and ΔAL. No differences in ΔSE (95% CI –0.08 to 0.11; p=0.759) or ΔAL (95% CI –0.04 to 0.01; p=0.190) were found between PM and non-PM groups, and neither metric improved PM discrimination. Conclusions Among high myopic individuals aged 18–25 years, 18.6% exhibited adult myopia progression and 40.0% showed axial elongation. Age and baseline AL were associated with adult myopia progression, but no clear link was found between adult myopia progression and the development of PM.