The Relation Between Grades Of Macular Perfusion And Foveal Thickness In Branch Retinal Vein Occlusion

Abstract

 

Purpose:

 

We graded perfusion status around the macula of branch retinal vein occlusion (BRVO) and assessed the relationship between the percentage area of these grades and the retinal thickness.

 

Methods:

 

Medical records of 83 BRVO patients were reviewed in this study. We classified the perfusion status into 3 grades: FPA (full perfusion area):normal fluorescein pattern with no retinal capillary change or minimally dilated vessels, PPA (partially perfusion area):patchy or arabesque pattern consisting of tiny hypofluorescence areas of partial capillary loss and hyperfluorescence with dilation and tortuosity of remaining capillary net, and NPA (non perfusion area): substantial hypofluorescence due to loss of capillary, pre-capillary arteriole and post-capillary venules (see Figure). We assessed the percentage of each area in a 2-disc-diameter, horizontal hemi-circle area of BRVO centered at the fovea, using IMAGEnet R4 (Topcon). Central foveal thickness (CFT) and average retinal thickness (ART) was measured by optical coherence tomography (OCT, Cirrus, Zeiss).

 

Results:

 

The median percentage of FPA, PPA and NPA were 24.8 % (interquartile range [IQR], 18.2-54.2), 26.4 % (IQR, 14.1-62.1) and 27.2 % (IQR, 0-35.7), respectively. A significant negative correlation was detected between CFT and FPA (r = 0.33, p=0.0045). Also, a positive correlation was identified between CFT and PPA (r = 0.35, p=0.0017). NPA has no correlation with foveal thickness.

 

Conclusions:

 

The partially perfused capillary area, but not the area of complete capillary loss seems to affect the macular thickness and edema occurring in BRVO. The result of less macular edema in the presence of a larger normal perfusion area may support the grading method of perfusion status employed in this study.  

 

Keywords: vascular occlusion/vascular occlusive disease • macula/fovea • edema