Features of the Choroidal Structures in Myopic Children Based on Image Binarization of Optical Coherence Tomography

Purpose: To evaluate the features of the choroidal structures in the eyes of myopic children obtained by enhanced depth imaging optical coherence tomography (EDI-OCT). Methods: Ninety-six myopic children with low to moderate myopia (spherical equivalent refractive error SER, -5.75 to -1.00 diopter) were included in this cross-sectional study. Ocular biometrics were measured using an optical low-coherence reflectometry device. Data of the choroidal structures extracted from a 7500-µm cross-sectional arc of the choroid extending from the temporal optic disc margin, including the total choroidal area, luminal area, stromal area, and choroidal vascularity index, were determined by image binarization of the EDI-OCT. Associations between demographic factors, ocular parameters, and choroidal structures were evaluated using univariate and multiple linear regression analyses. Results: The study participants (mean age, 11.02 ± 1.70 years) had a mean axial length (AL) of 24.94 ± 0.70 mm. The mean total choroidal area was 2.64 ± 0.49 mm2 (luminal area, 1.68 ± 0.32 mm2; stromal area, 0.95 ± 0.19 mm2), and the choroidal vascularity index was 0.64 ± 0.03. Multiple regression analysis showed that the luminal area was significantly associated with the AL (standard β = -0.24, P = 0.022) after adjusting for sex and corneal radius (CR), whereas the stromal area (standard β = -0.30, P = 0.003) and choroidal vascularity index (standard β = 0.36, P = 0.001) were significantly associated with age after adjusting for sex, CR, and lens thickness (LT). Sex, CR, LT, and SER showed no significant association with choroidal structures after adjusting for age and AL (all P > 0.05). Conclusions: The luminal area of the choroid tends to decrease with a longer AL, whereas the stromal area tends to decrease with increasing age in myopic children. These findings require further exploration in a longitudinal study.