# Evaluation of the retinal vasculature of patients with branch retinal vein occlusion using optical coherence tomography angiography

## TL;DR

This study uses optical coherence tomography angiography to show reduced retinal vascular density in patients with branch retinal vein occlusion and their unaffected eyes.

## Contribution

The study demonstrates early vascular changes in contralateral eyes, suggesting preclinical signs of hypertensive retinopathy.

## Key findings

- Affected eyes showed significantly lower vascular density compared to contralateral and normal eyes.
- Contralateral eyes also had reduced vascular density compared to normal eyes, indicating early changes.
- Adjustment for arterial hypertension eliminated the difference between contralateral and normal eyes.

## Abstract

To evaluate vascular density in super ficial and deep capillary plexuses of
the retina, measured using optical coherence tomography angiography in
patients with branch retinal vein occlusion. Affected eyes were compared
with the contralateral eye of the same patient and both were compared with
normal eyes.

A cross-sectional study including 16 previously untreated patients with
branch retinal vein occlusion. Patients with poor quality examinations,
bilateral disease, high refractive error, or any other retinal or choroidal
disease were excluded. A total of 31 patients without eye disease were also
selected as a comparison group. All participants underwent five optical
coherence tomography angiographies, and only those with at least two good
quality examinations were selected. The Kruskal-Wallis, Wilcoxon
signed-rank, and Mann-Whitney U tests were used for the statistical
analysis.

Vascular density was lower in affected eyes compared with contralateral eyes:
whole density (p=0.020 for capillary plexuses superficial; p=0.049 for deep
capillary plexuses) and parafoveal density (p=0.020 for capillary plexuses
superficial; p=0.011 for deep capillary plexuses). Vascular density was also
lower in affected eyes compared with normal eyes: whole density (p<0.001
for capillary plexuses superficial and deep) and parafoveal density
(p<0.001 for capillary plexuses superficial and deep). Whole density
(p=0.001 for capillary plexuses superficial and deep) and parafoveal density
(p=0.001 for capillary plexuses superficial; p<0.001 for deep capillary
plexuses) were both lower in the contralateral eyes compared with normal
eyes. Following adjustment for arterial hypertension, this difference was no
longer observed.

Vascular density in capillary plexuses and deep capillary plexuses was lower
in the eyes affected by branch retinal vein occlusion. Furthermore, the
lower vascular density noted in the contralateral eyes indicates that
changes most likely occurred in these eyes prior to the appearance of any
clinically detectable alterations, reflecting the early signs of
hypertensive retinopathy.