Among other factors, vascular density may be an important predictor of outcomes following BRVO. Photo: Carrie Ho, OD, Angella Gentry, OD, and Richard Zimbalist, OD. Click image to enlarge.

A recent study found that, when macular edema due to branch retinal vein occlusion (BRVO) completely resolves, retinal vascular density of the affected area is correlated with the corresponding retinal thickness. This suggests, according to the study authors, that vascular density may be a predictor of the final retinal thickness in this patient population.

This retrospective study included 46 patients with BRVO. The researchers analyzed the 46 affected eyes as well as 39 fellow eyes. They further divided the affected eyes into atrophy and non-atrophy groups.

When macular edema resolved after treatment with ranibizumab, the study authors obtained and analyzed OCT and OCT-A images. They quantitatively measured foveal avascular zone parameters, the extent of disruption of the ellipsoid zone, retinal thickness and the vascular density of the superficial vascular complex and deep vascular complex in the central fovea and minimal vascular density quadrant.

When compared with non-atrophy eyes, the data showed that superficial and deep vascular complex density were significantly lower in the atrophic group. The study authors also reported that these measures were strongly correlated with full retinal thickness.

Additionally, they observed a significant correlation between the disruption length of the ellipsoid zone and full-thickness and superficial vascular density. Multiple linear regression analysis showed a link between the disruption length of the ellipsoid zone and visual acuity before treatment as well as age with visual acuity with complete resolution of macular edema, according to the study authors.

The team concluded that “vascular density at the onset of the disease course may predict the final retinal thickness outcome,” they noted in their paper. “Severe decrease in vascular density may even result in retinal atrophy, which may cause visual acuity loss indirectly with the intermediate influencing factor of ellipsoid zone defects.”

Based on their findings, they concluded that visual acuity before treatment, the disruption extent of the ellipsoid zone and age may be significant factors impacting visual acuity with complete resolution of macular edema.

Leibovitzh GI, Trope GE, Buys YM, et al. Binocular summation of visual acuity at high and low contrast in early glaucoma. J Glaucoma 2022. August 17, 2022. [Epub ahead of print].