RETINAL VASCULITIS SEVERITY ASSESSMENT: Intraobserver and Interobserver Reliability of a New Scheme for Grading Wide-Field Fluorescein Angiograms in Retinal Vasculitis

PURPOSE: Wide-field fluorescein angiography is commonly used to assess retinal vasculitis (RV), which manifests as vascular leakage and occlusion. Currently, there is no standard grading scheme for RV severity. The authors propose a novel RV grading scheme and assess its reliability and reproducibility. METHODS: A grading scheme was developed to assess both leakage and occlusion in RV. Wide-field fluorescein angiography images from 50 patients with RV were graded by four graders, and one grader graded them twice. An intraclass correlation coefficient (ICC) was used to determine intraobserver–interobserver reliability. Generalized linear models were calculated to associate the scoring with visual acuity. RESULTS: Repeated grading by the same grader showed good intraobserver reliability for both leakage (ICC = 0.85, 95% CI 0.78–0.89) and occlusion (ICC = 0.82, 95% CI 0.75–0.88) scores. Interobserver reliability among four independent graders showed good agreement for both leakage (ICC = 0.66, 95% CI 0.49–0.77) and occlusion (ICC = 0.75, 95% CI 0.68–0.81) scores. An increasing leakage score was significantly associated with worse concurrent visual acuity (generalized linear models, β = 0.090, P < 0.01) and at 1-year follow-up (generalized linear models, β = 0.063, P < 0.01). CONCLUSION: The proposed grading scheme for RV has good to excellent intraobserver and interobserver reliability across a range of graders. The leakage score related to present and future visual acuity.