May 4, 2026
By Grace Kennedy
Photo Credit: Getty Images
It is well established that axial length elongates during childhood and mostly stabilizes by adulthood. There have been few reports of axial length elongation in adults with or without myopia, but no large-scale studies had been conducted.
Nishimura et al. (2026) addressed this gap by conducting a population-based longitudinal cohort study, investigating axial length (AL) elongation in 9,195 Japanese adults over a three- to five-year timeframe. The study demonstrates that axial length elongation can persist into adulthood, with 6.7% of participants displaying high axial length elongation (HALE) of greater than 0.033mm growth per year.
The main risk factors identified to be associated with AL elongation in adulthood were younger age, female sex and pre-existing high myopia, which aligns with the findings from previous studies. In addition, elevated levels of serum immunoglobulin E (IgE) were introduced as a potentially modifiable risk factor, suggesting a link between systemic inflammation and myopia progression.
The strengths of this study include its large sample size and prospective design with standardized ocular measurements. However, the limitations include its reliance on two time points for AL change and limited generalizability beyond a Japanese population. Overall, this study provides insight into myopia progression in adults and identifies potentially new pathological mechanisms to be investigated.
Abstract
Exploring Risk Factors for Axial Length Elongation: A Population-based Cohort Study of 9195 Eyes in Japan
Takayuki Nishimura, Hiroshi Kunikata, Naoko Takada, Makoto Ishikawa, Sayuri Tokioka, Rieko Hatanaka, Mana Kogure, Ippei Chiba, Kumi Nakaya, Taku Obara, Yoko Izumi, Akira Uruno, Satoshi Nagaie, Soichi Ogishima, Naoki Nakaya, Shinichi Kuriyama, Atsushi Hozawa, Nobuo Fuse, Toru Nakazawa
Purpose
To investigate long-term axial length (AL) changes in adults and to identify risk factors contributing to excessive AL elongation, which is associated with high myopia, we analysed a large dataset of adults without ocular pathology from the Tohoku Medical Megabank Project Community-based Cohort Study in Japan.
Methods
We conducted a longitudinal investigation of 9195 participants aged ≥20 years with several years of follow-up (mean 3.5 years). Based on the upper quartile of AL elongation for people aged in their 20s, we defined AL elongation exceeding 0.033 mm per year as high AL elongation (HALE). We used multiple logistic regression analyses to assess potential risk factors for HALE.
Results
A longitudinal investigation revealed that AL can fluctuate and even become elongated during adulthood, particularly among middle-aged and older individuals. Notably, HALE occurred in 618 out of 9195 eyes (6.7%). The proportion in each age group, comprising people aged in their 20s, 30s, 40s, 50s, 60s, 70s and 80s, was 24.7%, 12.7%, 9.4%, 5.2%, 4.5%, 4.0% and 1.4%, respectively. In addition, we also observed that younger age (OR 1.45 per 10 years older), female gender (OR 1.63), high myopia (OR 2.74) and serum immunoglobulin E (IgE) levels >171 IU/mL (OR 1.27) were associated with HALE.
Conclusion
Findings from a large prospective cohort study confirmed that in Japanese individuals, HALE was significantly associated with high serum IgE levels, as well as with younger age, female gender and pre-existing high myopia.
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Grace Kennedy is an optometrist who graduated from the University of Melbourne in 2023. After graduating, she went on to complete the Ocular Diseases Residency program at ACO Eye Health, working mainly across glaucoma and retina clinics while completing the Advanced Certificate in Glaucoma. With an interest in public health, she is actively involved in outreach optometry, providing eyecare to communities with limited access to optometric services. Most recently she has completed the ACO’s Certificate in Advanced Contact Lenses and has started to be involved in clinical teaching and pediatric clinics. |
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