Axial length normative data and percentile curves for schoolchildren in Taiwan: A tool for myopia monitoring.

Purpose: The prevention and control of myopia are crucial public health issues. Therefore, this study aimed to construct reference percentile curves of age-specific axial length based on population-based sampling data of Taiwanese children and assess their role in the progression of myopia using a cohort of children undergoing orthokeratology.

Methods: Data from 2997 representative samples of schoolchildren aged 6-18 years from a recent myopia survey in Taiwan between 2016 and 2017 were analysed for axial length distribution. Additionally, data from a cohort of 35 children with myopia treated with orthokeratology (mean follow-up period: 36.1 ± 14.6 months) were retrospectively collected. The ability to estimate myopia progression based on percentile change rate was compared with that of axial elongation rate through model comparisons involving linear and linear mixed-effect models.

Results: Percentile curves of the children's age-specific axial length were modelled and served as a population-based reference in Taiwan. The percentile change rate in the cohort of orthokeratology users showed a higher correlation (ρ = 0.64) with the myopia progression rate compared to the axial length elongation rate (ρ = 0.57). The baseline spherical equivalent and percentile change rate demonstrated the most effective performance in estimating myopia progression among all parameters.

Conclusions: Population-based reference percentile curves were established for age-specific axial length in Taiwanese schoolchildren, which can serve as valuable indicators for assessing individual health and monitoring vision trends within the population.