Microvascular Changes in the Cystic Lesion of Branch Retinal Vein Occlusion Imaged by Swept-Source Optical Coherence Tomography Angiography.

Introduction: This study aimed to describe the quantitative features of the microvasculature in the cystic lesions of branch retinal vein occlusion (BRVO).

Methods: A total of 43 eyes with BRVO, treated with anti-vascular endothelial growth factor therapy, were analyzed. Using wide-field swept-source optical coherence tomography angiography (OCTA), en face OCT images were obtained by depth-integrated reflectivity of the retina, and vascular density (VD), vascular length (VL), vascular lacunarity, and fractal dimension (FD) were evaluated in a 12 × 12-mm area of retinal nonperfusion.

Results: The mean area of affected lesions was 38.7 ± 19.8 mm², and cystic lesions were 8.5 ± 10.1 mm². VD, VL, and FD were significantly decreased in the cystic lesions compared to other affected lesions in the same eyes (p = 0.0010, p = 0.0001, and p = 0.0003, respectively) and in all eyes (p = 0.0281, p = 0.0050, and p < 0.0001, respectively). VD in cystic lesions within the vascular arcade (25 eyes) correlated with best-corrected visual acuity on OCTA (r = -0.433, and p = 0.0492).

Conclusions: Vascular structure in the cystic lesions was unpreserved compared to the other lesions in BRVO. These findings may help in understanding the pathophysiology of retinal edema in BRVO.