# Quantitative comparison of a novel wide-field OCT-angiography device with ultrawide-field fluorescein angiography in detecting retinal nonperfusion in vascular retinopathies

## TL;DR

This study compares a new wide-field OCT-angiography device with an existing standard for detecting retinal nonperfusion, showing it works well for mild to moderate cases but has limitations in severe cases.

## Contribution

First quantitative comparison of DREAM WF-OCTA with UWF-FA for retinal nonperfusion assessment.

## Key findings

- WF-OCTA showed strong correlation with UWF-FA for retinal ischemia assessment.
- Montage WF-OCTA had good agreement with UWF-FA in mild to moderate ischemia.
- Bland-Altman analysis revealed underestimation at higher nonperfusion levels.

## Abstract

Reliable assessment of retinal nonperfusion is critical in managing vascular retinopathies. While ultrawide-field fluorescein angiography (UWF-FA) is the clinical standard, it is invasive and dye-dependent. Previous wide-field optical coherence tomography angiography (WF-OCTA) systems have been limited by insufficient peripheral coverage. To the best of our knowledge, this is the first quantitative comparison of DREAM WF-OCTA with UWF-FA. The study leverages the device’s increased field of view (≈130° single scan, > 200° montage) and demonstrates that the previously published, semi-automated VMseg approach can also be applied to DREAM data.

24 eyes from 13 patients with diabetic retinopathy or retinal vein occlusion underwent both UWF-FA (Optos Silverstone, 200°) and WF-OCTA and were analyzed. The ischemic index (ISI) was calculated for each modality using previously developed semi-automated segmentation (VMseg) for WF-OCTA and manual annotation for UWF-FA. Agreement was assessed using correlation, linear regression, and Bland-Altman analyses.

ISI values from WF-OCTA showed strong correlations with UWF-FA (r = 0.92 for central, r = 0.96 for montage). Central WF-OCTA showed good absolute agreement with UWF-FA in mild ischemia, montage WF-OCTA with extended coverage in mild to moderate and partly severe ischemia. However, Bland-Altman analysis revealed proportional bias with increasing underestimation at higher nonperfusion levels, indicating that field of view limitations persist despite technological advances.

This study demonstrates that the DREAM OCT™ system with improved peripheral coverage enables reliable non-invasive assessment of retinal ischemia in mild to moderate cases. However, WF-OCTA should be considered complementary to UWF-FA, particularly in severe peripheral ischemia. Semi-automated segmentation enhances reproducibility and supports broader clinical adoption of OCTA in ischemia monitoring.

Ethics approval was granted by the Institutional Review Board of the Faculty of Medicine at LMU Munich (study ID: 24–0571), and the study was conducted following the principles of the Declaration of Helsinki. All participants provided written informed consent before inclusion in the study.