Abstract
Purpose :
There is limited data on myopia progression in early adulthood, especially pertaining to axial length (AL). The aim of this study was to monitor refractive error and AL over 12 months within a student cohort of young adults and estimate the rate of myopia incidence and progression.
Methods :
In a prospective longitudinal cohort study, 185 young adults aged between 18-25 years in higher education with a prescription of <+0.75DS spherical equivalent refraction (SER) at baseline were enrolled. Baseline measures of central SER with non-cycloplegic open-field autorefraction (NVision-K 5001, Shin Nippon: Japan) and AL (IOLMaster, Zeiss: Germany) were taken in October 2022 and then repeated after 6 and 12 months. Only participants who had measures for all timepoints were included. When determining AL change, those who displayed an increase in AL exceeding the repeatability of the IOLMaster (>+0.04mm), were categorised as ‘potential progressors’, while those with change ≤+0.04mm were labelled ‘non-progressors’.
Results :
Data were available for 125 participants. Participants had a median age of 20.4 years (interquartile range, IQR: 19.5-21.4 years), with the majority being female (64.8%) and of South Asian ethnicity (88.0%). Median baseline SER was -0.53D (-2.02 to 0.00D), while AL was 23.92mm (23.31-24.61mm). The percentage of myopic SERs increased from 54.4% at baseline to 56.8% at 12 months. Median change in SER was -0.03D/year (-0.22 to +0.14D/year) more myopic, while AL increase was +0.01mm/year (-0.02 to +0.05mm/year). At 12 months, 32.8% of participants were found to be potential AL progressors. For potential progressors, the median AL change was +0.06mm/year (+0.05 to +0.12mm/year) while for non-progressors this was -0.01mm/year (-0.04 to +0.02mm/year, p<0.001). For the potential progressors, the median AL increase from 0-6 months was +0.06mm (+0.03 to +0.10mm) versus +0.02mm (-0.01 to +0.05mm) between 6-12 months (p<0.05).
Conclusions :
A substantial proportion of young adults in full time education exhibit axial elongation. AL increase appears greater between October to March, suggesting a potential difference with seasonality.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.