# Retinal Characteristics in Eyes With Retinal Vein Occlusion Using Widefield Swept-Source Optical Coherence Tomography Angiography

## TL;DR

This study uses advanced imaging to examine blood vessel changes in eyes with retinal vein occlusion and how they relate to areas of poor blood flow.

## Contribution

The study introduces a custom widefield OCTA system to detect and analyze retinal vascular changes in RVO with high precision.

## Key findings

- NPAs were found in 69.1% of RVO eyes, with median size of 45.34 mm².
- Ghost vessels and collateral vessels were significantly correlated with larger NPAs.
- WF-OCTA imaging is a noninvasive tool for detecting vascular changes in RVO.

## Abstract

The purpose of this study was to investigate vascular alterations and their association with non-perfusion areas (NPAs) in eyes with retinal vein occlusion (RVO) using custom built widefield swept-source optical coherence tomography angiography (WF-OCTA) and ultra-WF color fundus photography (UWF-CF).

Patients with RVO and symptoms >3 months underwent single-capture 65 degrees WF-OCTA imaging using a custom-built prototype (A-scan rate: 1.7 megahertz [MHz]). Additionally, UWF-CF images were acquired. Retinal features, including collateral vessels (CVs), intraretinal/preretinal hemorrhage (IRH), intraretinal fluid (IRF), microaneurysms, crossing-signs (CS), neovascularization, ghost-vessels (GVs), exudates, foveal avascular zone (FAZ), and NPAs were graded on an extended Early Treatment Diabetic Retinopathy Study (ETDRS) grid up to 18 mm. NPAs were annotated manually on en face images using Fiji. The presence of retinal findings was then correlated with NPA size.

Eighty-one eyes (48 right eyes and 33 left eyes) of 81 patients (women = 50.6%, mean age = 65 ± 12.4 years old) were analyzed. Thirty-three eyes (40.7%) suffered from central RVO (CRVO) and 48 (59.3%) from branch RVO (BRVO) with a median disease duration of 25 months (11–53 months). NPAs were found in 69.1% of eyes (n = 56, CRVO = 69.7%, n = 23; BRVO = 68.8%, n = 33) with a median size of 45.34 mm2 (11.39–81.39). Significant correlations between NPA size and CVs (P = 0.002, rs = 0.344, confidence interval [CI] = 0.136–0.523), NPA size and GVs (P < 0.001, rs = 0.49, CI = 0.302–0.64) as well as FAZ size and BCVA (P < 0.001, rs = −0.429, CI = −0.593 to 0.231) were found.

GVs may be indicators of underlying NPAs in RVO. For BRVO, CVs, IRF, IRH, and CS may be indicators for underlying NPAs. The 65 degrees WF-OCTA-imaging allows for precise noninvasive detection of vascular alterations in eyes with RVO and may serve as a useful adjunct in clinical practice.