Assessment of non-proliferative diabetic retinopathy severity level using ultra-widefield Clarus versus conventional five-field and ultra-widefield Optos fundus imaging

Abstract Purpose To compare diabetic retinopathy (DR) severity level and the abilities in detecting early DR lesions among conventional five-field, ultrawide-field (UWF) Optos, and UWF Clarus fundus imaging methods. Methods This was a single-center, prospective, clinic-based, and comparative study. In total, 157 consecutive patients with diabetes mellitus were enrolled in this study. All patients underwent comprehensive ophthalmological examinations. Following induction of mydriasis, each eye was examined by conventional five-field, UWF Optos, and UWF Clarus fundus imaging methods. All images were graded using the International Clinical DR severity scale. DR grades were compared and analyzed by weighted kappa statistics among the three fundus imaging methods. Results In total, 157 consecutive patients with diabetes (302 eyes) were enrolled in this study. Weighted kappa statistics for agreement were 0.471 (five-field vs. covered optimized Optos), 0.809 (five-field vs. covered Clarus), 0.396 (covered optimized Optos vs. covered Clarus), 0.463 (five-field vs. optimized Optos), 0.521 (five-field vs. Clarus 133°), 0.500 (five-field vs. Clarus 200°), 0.323 (optimized Optos vs. Clarus 133°), 0.349 (optimized Optos vs. Clarus 200°),0.976 (Clarus 133° vs. Clarus 200°), and 0.491(optimized Optos vs. red-free channel Optos). The area under curve of covered Clarus images was higher than that of conventional five-field images at three different thresholds. Conclusion Compared with conventional five-field and optimized Optos fundus imaging methods, Clarus fundus imaging methods exhibited excellent performance in assessing NPDR severity. Compared with optimized Optos, red-free channel Optos can detect more small lesions. Thus, Clarus and red-free channel Optos fundus imaging methods were superior for early detection of DR.