Comparison between Early Treatment Diabetic Retinopathy Study 7-field retinal photos and non-mydriatic, mydriatic and mydriatic steered widefield scanning laser ophthalmoscopy for assessment of diabetic retinopathy

AimsTo compare non-mydriatic, mydriatic and steered mydriatic widefield retinal images with mydriatic 7-field Early Treatment Diabetic Retinopathy Study (ETDRS)-standards in grading diabetic retinopathy (DR).MethodsWe examined 95 patients (190 eyes) with type 1 diabetes. A non-mydriatic, a mydriatic and four steered mydriatic 200° widefield retinal images were captured (Optos 200Tx, Optos plc, Dunfermline, Scotland) and compared to mydriatic 7-field 45° ETDRS images (Topcon 3D OCT-2000, Topcon, Tokyo, Japan). Images were graded for DR according to ETDRS-protocol by a trained and certified grader masked to the results of the corresponding grading. For agreement kappa-statistics were used.ResultsExact level agreement with 7-field images was found in 76.3%, 76.1% and 70.7% for non-mydriatic, mydriatic and steered mydriatic widefield images, respectively. Corresponding values for one-level agreement were 99.0%, 98.9% and 99.5%, respectively. Non-mydriatic matched mydriatic widefield images almost fully with exact and one-level agreement of 96.8% and 100.0%, respectively. Mydriatic steered images resulted in higher grading in 24 eyes.ConclusionsWidefield images matched 7-field images favorably. Widefield images can be captured without pupil-dilation and only one image is needed. However, because of overlapping eyelashes and distortion some lesion might be missed. Mydriatic steered images in selected cases may solve some of these problems.