Choroidal Thickness Distribution and Its Association With Axial Length and Spherical Equivalent in Schoolchildren Assessed by Wide-Field Swept-Source Optical Coherence Tomography.

Purpose: The purpose of this study was to evaluate the distribution of choroidal thickness (ChT) in schoolchildren using wide-field swept-source optical coherence tomography (SS-OCT) and to investigate its association with axial length (AL) and spherical equivalent (SE).

Methods: This prospective study included 176 eyes from 88 healthy Japanese schoolchildren aged 6 to 15 years (mean age = 9.9 ± 2.4 years). Wide-field SS-OCT was used to measure ChT across a 57 degrees × 57 degrees fundus area. After excluding poor-quality images, 169 eyes were included in the final analysis. The ChT distribution was evaluated by dividing the obtained images into a 3 × 3 grid comprising 9 sections. ChT measurements were performed automatically with custom-designed software. ChT values were compared among the nine regions, and correlations with AL and SE were assessed for each grid section. Additionally, the findings in schoolchildren were compared with historical data from adults.

Results: Mean ChT values across the 9 regions ranged from 172 ± 29 µm in the nasal-inferior region to 307 ± 39 µm in the temporal region. The choroid was thicker in the temporal and macular regions and thinner around the optic disc and inferior regions. Significant negative correlations were found between ChT and AL across all regions (R = -0.50 to -0.23, P < 0.05), indicating that longer ALs were associated with thinner choroids. Similarly, significant positive correlations were observed between ChT and SE (R = 0.19 to 0.55, P < 0.05), demonstrating that higher degrees of myopia were associated with thinner choroids. Moreover, ChT in schoolchildren was generally thicker compared to that in adults.

Conclusions: This study provides a detailed analysis of ChT distribution in schoolchildren, revealing regional variability and a generally thicker choroid compared with adults. The significant correlations between ChT, AL, and SE across all regions suggest a potential role for ChT in ocular growth and myopia progression. These findings underscore the need for longitudinal studies to investigate causal relationships between ChT distribution and myopia development.

Translational relevance: Wide-field choroidal mapping identifies early structural biomarkers for pediatric myopia progression and control.