Association Between Changes In Choroidal Thickness And Ocular Higher Order Aberrations In Japanese Schoolchildren

With the global increase in the prevalence of myopia, the role of higher order aberrations (HOAs) in myopia progression has gained growing attention. HOAs, which cannot be fully corrected by conventional optical methods, induce various visual distortions and may influence ocular growth. Additionally, choroidal thickness (CT) is being evaluated as one of the parameters that promotes myopia progression, in that a decrease in CT is associated with myopia progression. However, the relationship between HOAs and CT remains unclear. Therefore, we aimed to investigate the association between changes in the CT and HOAs in schoolchildren.

This prospective, observational, school-based study was conducted with the approval of the Keio University School of Medicine Ethics Committee (approval number: 20160457). The parents of all students provided informed written consent. In the first year (2023), the study targeted third-grade elementary school students. A total of 135 elementary school students in Tokyo, Japan, were enrolled and examined from 2023 to 2024.

We measured the spherical equivalent (SE), axial length (AL), CT, and ocular HOAs of a 4-mm pupil. The CT was analyzed in 3 concentric zones centered on the fovea: C0 (1 mm), C1 (1–5 mm), and C2 (5–9 mm). C1 and C2 were further divided into superior/inferior/nasal/temporal subregions, totaling 9 regions. Correlation analyses examined the relationships between the ΔC0, ΔSE, and ΔAL. Multiple regression analyses were performed using the ΔCT in each region as the dependent variable, with the total HOA (THOA: root mean square values from the 3rd- to 6th-order Zernike coefficients), baseline CT, sex, body mass index (BMI), time spent outdoors, reading/study time, and family history of myopia as independent variables. The right eye was analyzed.

At baseline, the SE (the mean ± SD) was -1.63 ± 1.57 diopters, AL 23.40 ± 0.78 mm, and C0 308.8 ± 63.1 μm. The ΔC0 was -19.5 ± 30.1 μm and correlated significantly with the ΔSE (R=0.346, P=0.004) and ΔAL (R=-0.326, P<0.001). Multiple regression analysis showed that a higher THOA was associated significantly with greater thinning in the C0, temporal C1, temporal C2, and nasal C1 (all P<0.05). In all regions, a thicker baseline CT predicted greater thinning, and a higher BMI was associated with CT thickening (all P<0.05). Additionally, children with two myopic parents exhibited significant thinning in the nasal C2 region (P<0.05).

The changes in the CT during the school-age years were associated with the ocular THOA, baseline CT, BMI, and family history of myopia.