Vascular Morphology of the Retina and Choroid in Young Adults with Myopia Based on Optical Coherence Tomography Angiography

Purpose This study aims to evaluate changes in retinal and choroidal vascular morphology in young adults with myopia using swept-source optical coherence tomography angiography (SS-OCTA). Methods We conducted comprehensive ophthalmic examinations, obtained SS-OCTA scans (12 × 12 mm ² ), and documented the clinical characteristics of the participants. Eyes were categorized into low, moderate, and high myopia groups based on spherical equivalent refraction. Average vessel density and morphological parameters were quantitatively analyzed using a semi-automated MATLAB program. Vessel area density was further assessed across nine grids using angiography analysis software. Results The retinal vessel diameter index was significantly lower in the high myopia group than that in the low and moderate myopia groups ( P  = 0.021 and P  = 0.029, respectively), and showed an inverse correlation with axial length ( P  < 0.001). The retinal vessel complexity index was significantly higher in the high myopia group than that in the low myopia group ( P  = 0.008), and positively correlated with axial length ( P  = 0.001). No significant differences were observed in retinal average vessel density among the three groups ( P  = 0.491). In addition, choroidal average vessel density, vessel skeleton density, vessel perimeter index, and vessel complexity index were reduced in the high myopia group ( P  = 0.004, P  = 0.007, P  = 0.022, and P  = 0.037 respectively). The vessel diameter index of choroidal Sattler’s and Haller’s layers (CSHL) was notably higher in the high myopia group than that in the low myopia group ( P  = 0.021), demonstrating a positive correlation with axial length ( P  < 0.001). Conclusions As axial length increases, modifications in retinal vascular morphological parameters, such as diminished retinal vessel diameters and enhanced retinal branching, are observed to precede alterations in the average retinal vessel density. Additionally, in cases of high myopia, significant changes are evident in both choroidal vessel density and vascular morphology.