Design and baseline characteristics of a prospective, longitudinal study of myopia progression in young adults (MAP)

Adult myopia is not well understood, with limited studies investigating the factors that influence its progression during and beyond adolescence. Understanding myopia progression and the associated risk factors in adulthood would help clinicians identify young adult myopes at greater risk of progression, ensuring they receive appropriate clinical attention.

Myopia progression in young adults (MAP) is a 1-year prospective, longitudinal, multicentre study to document the progression of myopia and associated risk factors in young adults. The aim of this article is to report the baseline characteristics of the study population.

Participants between 18 and 26 years of age and spherical equivalent refractive error (SER) between -0.50 and -6.00 D were recruited at two sites: Sydney and Ho Chi Minh (HCM). Data, including central and peripheral cycloplegic refractive errors, central and peripheral axial length (AL), and myopia-related lifestyle factors, were recorded at baseline and will be collected every 6 months.

One-hundred and twenty-six young adults (63 participants at Sydney and HCM, respectively) aged 21.3 ± 2.3 years (20.6 ± 2.3 vs 22.0 ± 2.0, p < 0.001), SER of -2.8 ± 0.8D (-2.7 ± 1.3 vs -3.0 ± 1.1, p = 0.17), and AL 24.8 ± 0.8 mm (25.0 ± 0.8 vs 24.7 ± 0.8, p = 0.033) were enrolled.The overall sample included 98 (77.8%) Asians, with 35 (79.4%) in Sydney and 63 (100%) in HCM. Myopes in HCM reported an older age at the onset than myopes in Sydney (p < 0.001). In HCM, greater time was spent on screens (p = 0.030) and less time spent outdoors than in Sydney (p < 0.001). Multivariate analysis indicated that younger age at onset was associated with a longer baseline AL, a more myopic baseline SER and females had a shorter baseline AL.

The design and baseline characteristics of MAP are reported. Baseline analyses indicate that younger age at onset is associated with more myopic SER and longer AL in young adults.