# Ultrawide-Field Optical Coherence Tomography Angiography-Guided Navigated Laser Therapy of Non-Perfused Areas in Branch Retinal Vein Occlusion

## TL;DR

This study shows that ultrawide-field OCTA can guide laser therapy for retinal vein occlusion, though minor placement errors occurred.

## Contribution

Demonstrates the feasibility of using UWF-OCTA for precise laser treatment planning in BRVO.

## Key findings

- UWF-OCTA images from three devices were successfully integrated into the laser navigation system.
- Laser spots deviated slightly from planned locations, especially in mid-periphery areas.
- Treatments successfully targeted non-perfused areas but did not always avoid normal and collateral vessels.

## Abstract

Background/Objectives: This study evaluates whether ultrawide-field optical coherence tomography angiography (UWF-OCTA) can guide navigated laser therapy for non-perfused areas (NPAs) in branch retinal vein occlusion (BRVO). It further explores whether the laser spots can be accurately placed according to plan, considering that the retina is three-dimensional (3D), while UWF-OCTA provides two-dimensional (2D) images. Methods: UWF-OCTA images from three devices—VG200, Xephilio OCT-S1, and Bmizar—guided the treatments. These images were superimposed onto NAVILAS® system images to guide NPA treatments. Pre-treatment planning was strategically designed to avoid normal and collateral vessels, with immediate post-laser OCTA and en face images assessing the efficacy of the laser spots in avoiding these vessels as planned. The accuracy of navigated laser therapy was further analyzed by comparing the intended laser locations with the actual spots. Results: All montaged OCTA images from the three devices were seamlessly integrated into the navigated laser system without registration errors. All patients received treatments targeting the NPAs as planned. However, not all collateral or normal vessels were successfully avoided by the laser spots. A further analysis revealed that the actual locations of the laser spots deviated slightly from the planned locations, particularly in the mid-periphery areas. Conclusions: UWF-OCTA-guided navigated laser photocoagulation is feasible and precise for treating NPAs in BRVO. Nonetheless, minor deviations between planned and actual locations were observed. This discrepancy, particularly important when treating diseases of the macular area, should be carefully considered when employing OCTA-guided navigated laser photocoagulation.