Abstract
Purpose::
The current standard for grading diabetic retinopathy in clinical trials is 7-field stereo photography of the fundus in diagnostic mydriasis. In terms of image quality, the FF450plus camera (Carl Zeiss Meditec AG, Jena) defines a high-quality reference standard. The aim of the study was to investigate if the new non-mydriatic digital fundus camera VisucamPRO NM could serve as an alternative for clinical trials requiring 7-field stereo photography.
Methods::
A total of 128 eyes of diabetic patients were enrolled in the randomized, controlled, prospective trial. In random order 7-field stereo photography was performed with the Visucam and the FF450 camera, both in diagnostic mydriasis. The resulting 256 image sets from the two camera systems were graded for retinopathy levels and image quality (Scale 1-5), both anonymized and blinded to the image source.
Results::
On FF450 stereoscopic imaging, 20% of the patients had no or mild diabetic retinopathy (ETDRS Level<=20) and 29% had no macular edema. No patient had to be excluded due to image quality. The retinopathy level did not influence the quality of grading or of images. Excellent overall correspondence was obtained between the two fundus cameras regarding retinopathy levels (kappa 0.87) and macular edema (kappa 0.80). In diagnostic mydriasis the image quality of the Visucam was graded slightly better than that of the FF450 (2.20 vs. 2.41; p<0.001), especially for pupils <7mm.
Conclusions::
The non-mydriatic VisucamPRO NM offers good image quality and is suitable as a more cost-efficient and easy-to-operate camera for clinical trials requiring 7-field stereo photographs.
Keywords: imaging/image analysis: clinical • diabetic retinopathy