Highlight
• Development of the first large-scale, region- and sex-specific axial length (AL) centile charts for children and adolescents based on pooled global data.
• Confirmed significant regional differences in AL growth trajectories, especially pronounced at higher percentiles, indicating differing myopia progression risks.
• Robust agreement between modeled AL centile curves and empirical data, enabling reliable clinical and research applications.
• These charts may enhance early identification of atypical axial elongation and guide personalized myopia prevention and management strategies worldwide.
Study Background
Myopia, or nearsightedness, has emerged as a global public health concern due to its growing prevalence and associated risk for sight-threatening complications such as retinal detachment, glaucoma, and myopic maculopathy. Axial elongation of the eye is the primary anatomical factor underlying myopia progression. Since controlling axial length growth is the cornerstone for myopia management, having accurate, population-specific reference data for axial length in children and adolescents is critical. Yet, standardized axial length growth references covering diverse geographic populations and accounting for sex differences have been lacking. This gap hinders the ability of clinicians and researchers to accurately identify abnormal axial growth and to evaluate myopia control interventions across populations.
Study Design
This study conducted a pooled cohort analysis using individual participant data obtained from population- and school-based studies collated by the CREAM-Kids Consortium. The dataset included 147,404 children and adolescents contributing a total of 559,799 axial length measurements. Participants originated predominantly from East Asia (84%, ages 6-18 years), followed by Europe (12%, ages 6-21 years) and Australia (4%, ages 6-21 years). Due to data compatibility, European and Australian data sets were combined for analytical purposes. The data span from 1999 through 2024, with statistical analysis performed between December 2024 and May 2026. Primary exposures considered were axial length, age, sex, and geographic region. Main outcomes comprised sex- and region-specific axial length centile curves modeled across the age range and their validation against empirical measurement data.
Key Findings
The study revealed clear regional and sex-based differences in axial length distribution during childhood and adolescence. For female participants at age 7, the median (50th centile) axial length was 22.35 mm in Europe and Australia combined, compared to 22.67 mm in East Asia. By age 18, this median increased to 23.31 mm and 24.36 mm respectively, reflecting a larger eye size and possibly greater myopia prevalence in East Asian populations.
Regional disparities were especially notable at the extremes of the axial length distribution. At age 7 in females, the difference between East Asia and Europe/Australia at the 3rd centile was 0.33 mm, increasing to 0.50 mm at the 97th centile. By 18 years of age, these differences grew to 0.73 mm at the 3rd centile and a clinically meaningful 1.27 mm at the 97th centile. Such differences underscore higher axial elongation trajectories and likely higher myopia burdens in East Asian youths.
The sex differences across regions were also consistent, with males generally exhibiting slightly longer axial lengths compared to females across ages.
The developed centile curves demonstrated excellent agreement with observed empirical values, with intraclass correlation coefficients exceeding 0.99 and minimal measurement bias (ranging from -0.08 mm to 0.04 mm), confirming the models’ precision and clinical reliability.
Expert Commentary
This study’s strength lies in its unprecedented large sample size and global representation covering key myopia-affected populations. It provides critical normative data to help ophthalmologists and optometrists contextualize axial length measurements in clinical practice according to age, sex, and regional background. Clinicians can better identify children experiencing accelerated eye growth who may benefit from early myopia interventions such as atropine drops, orthokeratology, or environmental modifications like increased outdoor activity.
However, the authors note limitations including the non-exclusive reliance on purely population-based cohorts, which could introduce selection biases. Furthermore, while the dataset reflects major global regions, other ethnic or geographic groups remain underrepresented, potentially limiting generalizability. Longitudinal changes beyond adolescence are also not covered. Despite these, the robust modeling and validation approach strengthen confidence in these charts as valuable references.
Current international myopia management guidelines advocate for growth monitoring of axial length as a standard of care; these centile charts provide a much-needed quantitative tool to operationalize that recommendation worldwide.
Conclusion
The global, region- and sex-specific axial length centile charts developed in this comprehensive pooled cohort study fill an important knowledge void in pediatric ophthalmology. These normative growth curves enable improved identification of abnormal axial elongation patterns associated with myopia development across diverse populations. Clinicians and researchers now have a validated reference to support early diagnosis, targeted management, and evaluation of myopia control strategies. Ultimately, widespread clinical application of these charts could play a vital role in mitigating the global burden of myopia-related visual impairment.
Funding and Trial Registrations
The study was conducted by the CREAM-Kids Consortium, supported by international research grants dedicated to ocular epidemiology and myopia control. No individual clinical trial registration applies as this was a pooled observational study.
