Consider Population Characteristics in AL Changes When Evaluating Myopia Control Studies

Assessing axial length (AL) changes is vital in determining the efficacy of myopia control, so close examination of AL growth in relation to myopia is necessary. With the growing use of emmetropic benchmarks and controls that take into account physiological eye growth during evaluation of myopia control efficacy with AL outcomes, it is crucial to apply physiological eye growth rates from a similar source population in terms of ethnicity, setting and country.Researchers recently evaluated the physiological and myopic eye growth among children in Wenzhou, China, in comparison to other populations. They noted that the largest variations in eye growth rates were observed between their study and the predominantly Caucasian population in the Orinda Longitudinal Study of Myopia (OLSM) in the US, which lined up well with their hypothesis of having the most variation between populations of distinct ethnicities in different countries.The Wenzhou Medical University-Essilor Progression and Onset of Myopia (WEPrOM) cohort study examined physiological and myopic eye growth using data from 700 non-myopic (spherical equivalent [SE] > -0.5D for at least two years) and 297 myopic (SE ≤ -0.5D) schoolchildren, respectively, aged seven to nine years at baseline, with a follow-up of 4.5 years. The mean age in each group was 9.14 and 9.77, respectively. The mean SE and AL were 0.23D and 23.04mm for the data used for examining physiological eye growth and -1.81D and 24.26mm for the data used for examining myopic eye growth, respectively.Using longitudinal data from the WEPrOM study, the researchers estimated physiological eye growth (50th percentile in one-year change in AL) to range from 0.22mm/year to 0.12 mm/year and estimated myopic eye growth (50th percentile in one-year change in AL) to range from 0.52mm/year to 0.27 mm/year for Chinese children aged seven to 12 years.   Considering axial growth rates in similar populations is key to evaluation of myopia control, researchers say. This graph from the study shows considerable variation between cohorts of different ethnic/racial groups. Photo: Wong YL, et al. Am J Ophthalmol. August 7, 2025. Click image to enlarge. As anticipated, with the same ethnicity and similar settings in China, physiological and myopic eye growth rates in this current study (Wenzhou) were comparable with those of Chinese children in Guangzhou and Shanghai. Conversely, despite having Asian ethnic origins, the eye growth rates among Singaporean children are lower than that of children in China, which could be due to factors such as the inclusion of a portion of Malay and Indian children who tend to have less myopia and less intense education pressure in early childhood in Singapore.“Such differences in physiological and myopic eye growth among children from various populations have implications on the new approaches that evaluate myopia control efficacy centered around assessment of AL changes,” the study authors wrote in their paper, which was published in American Journal of Ophthalmology.They did note that, with the significant loss-to-follow-up (56%) observed in the last 4.5-year follow-up visit, the sample of participants who were 11 years and older was lower, which contributed to the less stable estimates for this older age range. Also, the inclusion of non-myopic children who later develop myopia during the follow-up period in both the evaluation of physiological and myopic eye growth may have potentially overestimated physiological eye growth, as the physiological eye growth between persistent non-myopes and those who develop myopia during later childhood or adolescence may not be the same. Click here for the journal source. Wong YL, Yuan Y, Ye Y, et al. Variations in physiological and myopic eye growth among children from different populations. Am J Ophthalmol. August 7, 2025. [Epub ahead of print]. This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.