Retinal and choroidal structure and vascularity in Chinese emmetropic and myopic children

Purpose: This study evaluated the structural features of the retinal and choroidal regions and their correlations with ocular biometric and vascular parameters in Chinese children using optical coherence tomography angiography (OCTA). Methods: A total of 159 children, 6-13 years of age, were included in this prospective study. The sample consisted of 55 emmetropes (spherical equivalent <= +0.75 and > -0.50 D), 53 low-moderate myopes (> -0.50 to > -6.00 D) and 51 high myopes without pathological changes (<= -6.00 D). Optical coherence biometry was used to measure axial length (AL) and anterior segment parameters. Swept-source optical coherence tomography/OCTA was used to assess the macular structures and vascular characteristics in a 6 x 6 mm region centred on the macula. Results: In a comprehensive analysis adjusting for age, sex, AL, macular blood perfusion, intraocular pressure and anterior segment parameters, retinal thickness (RT) showed a significant positive association with deep retinal vascular density and superficial retinal vascular density in the foveal area, but not with AL. Moreover, RT exhibited a significant negative association with AL in the parafoveal and perifoveal regions. Further, a significant positive correlation was observed between choroidal thickness and both choroidal vascular volume and choriocapillaris perfusion area, along with a negative correlation with AL across the entire macular region. Conclusions: This study showed that the thickness of retina and choroid in Chinese children was not only associated with AL but also showed dynamic properties such as the blood perfusion of the retina and choroid, particularly in the foveal area.