Complexities in the Terminology Used for Describing, Diagnosing, and Classifying Retinal Vasculitis: A Scoping Review from the International Uveitis Study Group (IUSG) Retinal Vasculitis Study (ReViSe)–Report 6

Background: Retinal vasculitis (RV) is a complex inflammatory condition that affects the retinal vessels, often presenting as perivascular sheathing, vascular leakage, and occlusion. Despite its well-documented clinical and angiographic features, the definition and classification of RV remain inconsistent across clinical and research settings. This lack of uniformity has led to challenges in diagnosis, management, and understanding of research findings. Thus, this scoping review aims to objectively identify any ambiguity in the terminology of RV and discuss possible reasons for it, laying the groundwork for a subsequent panel of experts to provide consensus definitions for RV through a Delphi process. Methods: This review included 97 studies. The authors extracted and summarised data on the definitions and diagnostic criteria used for RV, the definitions used for subtypes of RV (e.g. isolated, idiopathic, undifferentiated, primary RV), the imaging modalities used for RV diagnosis, and any references to existing guidelines. Results: The results confirmed a significant degree of ambiguity in RV terminology. Among the 17 papers that explicitly defined RV in their methodology, four distinct definitions emerged. We also found that the terms’ idiopathic,’ ‘primary,’ and ‘undifferentiated’ RV were often used interchangeably, despite reflecting distinct aspects of the disease. Notably, all 52 studies that noted the diagnostic modalities used included fluorescein angiography, although the usage of other modalities was contentious. Conclusion: There are significant inconsistencies and ambiguities in defining and classifying RV, highlighting the need for a standardized, consensus-based framework to improve clarity and consistency in both research and clinical practice.