UWF-SS-OCTA evaluation of changes of choroidal microvasculature and microstructure in adult patients with high myopia and relationship with age and axial length

Objective: This study aimed to evaluate the changes of choroidal microvasculature and microstructure in adult patients with high myopia by ultra-wide-field swept-source optical coherence tomography angiography (UWF-SS-OCTA) and explore the relationship with age and axial length. Methods: Adopting a cross-sectional study design, 15 normal subjects (26 eyes) admitted from January 2025 to June 2025 were enrolled as control group, and 39 patients with high myopia (72 eyes) were collected as high myopia group. Each eye underwent 6 mm × 6 mm and 24 mm × 20 mm SS-OCTA scans centered on the macular central fovea and optic disk, respectively. Each B-scan position was scanned four times, with the mean value taken. Macular thickness, axial length (AL), spherical equivalent (SE), linear density, choriocapillaris flow density (CCD), three-dimensional choroidal vascularity index (3D-CVI) and choroidal vascular volume per unit area (CVV/A) were compared between high myopia group and control group. Multivariate linear regression analysis was conducted to analyze the relationship of UWF-SS-OCTA indicators with AL and SE. Results: < 0.05). Taking AL as the dependent variable and incorporating age, eye side, mean linear density, CCD, 3D-CVI, CVV/A and SE as independent variables, multivariate linear regression analysis found that CCD (β: -0.25; 95% CI: -0.44 ∼-0.07) and SE (β: -0.16; 95% CI: -0.24 ∼-0.08) were independently associated with AL. Conclusion: Patients with high myopia exhibit reduced mean CCD, 3D-CVI and CVV/A. Higher mean CCD value correlates with shorter axial length.