Study of Macular Capillary network changes after branch retinal vein occlusion (BRVO) on optical coherence tomography angiography (OCT-A).

Abstract

Branch retinal vein occlusion (BRVO) is the focal occlusion of a first or second-order branch of a retinal vein, which occurs most frequently at an arteriovenous (AV) crossing. Direct ophthalmoscopy, color fundus photography, and fluorescein angiography facilitate observation of AV crossings parallel to the retinal plane. Aim and objectives: To analyze the macular microvasculature changes in eyes with branch retinal vein occlusion (BRVO) using optical coherence tomography angiography (OCT-A). Subjects and methods: A total of 40 eyes(mean age 64.2 ± 8.02 range between 52 years and76 years) 20 of them were recently diagnosed with BRVO( i.e. patient had fundus findings such as intraretinal hemorrhages, cotton wool spots, macular edema, and vascular congestion) and other 20 eyes were healthy and served as control, all of them were evaluated by optical coherence tomography angiography (XR-Avanti; Optovue). The macular angiography scan protocol covered a 6 mm x 6 mm area. The angiography analysis focused on two retinal layers: a superficial and deep vascular networks. The following vascular morphological parameters were assessed at the foveal area in both the superficial and deep networks: foveal avascular zone area diameter, foveal vascular density, capillary non-perfusion occurrence, foveal avascular zone distribution (i.e. loss of the intact perifoveal capillary arcade greater than one quadrant)(3), presence of cystoid spaces and collaterals connecting the occluded vein to an adjacent patent vein Results: there was an increase in superficial vascular density in patients than control group respectively (p < 0.001) ( 29.38±9.79, 16.41±5.61).