Choroidal thickness and myopia in relation to physical activity - the CHAMPS Eye Study

To describe the relationship between choroidal thickness (CT) and myopia in relation to physical activity (PA) in a population-based child cohort.

In a prospective study of 307 children from the CHAMPS Study Denmark, we used objective data from GT3X accelerometer worn at four periods between 2009 and 2015 to determine the amount and intensity of PA. Intensity was estimated as counts/minutes, and cut-off points were defined at four intensity levels. Eye examinations were performed in 2015 and included autorefraction in cycloplegia, axial length (AL) by biometric and fovea-centred enhanced depth imaging optical coherence tomography. By a semi-automated method, we measured the CT at 17 targets per eye representing anatomically different locations (subfoveal, 1 and 3 millimetre in each direction of fovea).

Mean age at the eye examination was 15.4 ± 0.7 years. The mean AL was 23.5 ± 0.9 mm, and the mean subfoveal CT was 369 ± 87 μm. Choroidal thickness (CT) was 331 ± 68 μm for the overall macula, 355 ± 78 μm for the 1-mm zone and 304 ± 60 μm for the 3-mm zone. All CT measurements were thinner in myopic eyes (p < 0.0001) and in boys (p < 0.05). We found no association between total PA and the CT by either mixed model analysis (p = 0.074) or linear regression by any intensity levels (p = 0.22, p = 0.15 and p = 0.43).

Among adolescents aged 14-17 years, there was no association between objective PA exposures and the CT, AL or refractive error.