Reliability of Clinical Grading of Diabetic Retinopathy Compared to Grading of Ultra-widefield Images

Abstract

Purpose: Evaluate the reliability of clinical grading of diabetic retinopathy (DR) severity compared to grading on ultra-widefield pseudocolor fundus (UWF-CF) and ultra-widefield fluorescein angiography (UWF-FA) images and their relative detection of sight-threatening DR (STDR) and referable DR. Methods: We analyzed 184 diabetic eyes. UWF-CF and UWF-FA images were graded based on the International Clinical Diabetic Retinopathy (ICDR) severity scale. Agreement between clinical and UWF-based severity grading was evaluated using Cohen’s kappa coefficient. The rate of STDR and referable DR was evaluated for each grading method. Results: We found moderate agreement between clinical grading and UWF-CF (k=.456, p <.001) and between UWF-CF and UWF-FA (k= .443, p <.001). Agreement between clinical grading and UWF-FA was fair (k=.397, p <.001). UWF-based grading identified a higher DR grade in 56 eyes (30%) on UWF-CF and 85 eyes (46.2%) on UWF-FA. Compared to clinical grading, UWF-FA detected a higher rate of STDR (44%; 81/184 vs 22.3%; 41/184), while UWF-CF detected more referable eyes (58.1%;107/184 vs 45.65%;84/184). Conclusion: UWF-CF is a valuable tool for identifying referable eyes and can be a useful, non-invasive adjunct to clinical grading. Our results suggest that UWF-FA is particularly useful for detecting unsuspected STDR in eyes with clinically referable DR.