Characterization of the retinal vasculature in fundus photos using the PanOptic iExaminer system

Background:The goal was to characterize retinal vasculature by quantitative analysis of arteriole-to-venule(A/V)ratio and vessel density in fundus photos taken with the PanOptic iExaminer System.Methods:The PanOptic ophthalmoscope equipped with a smartphone was used to acquire fundus photos centered on the optic nerve head.Two fundus photos of a total of 19 eyes from 10 subjects were imaged.Retinal vessels were analyzed to obtain the A/V ratio.In addition,the vessel tree was extracted using deep learning U-NET,and vessel density was processed by the percentage of pixels within vessels over the entire image.Results:All images were successfully processed for the A/V ratio and vessel density.There was no significant difference of averaged A/V ratio between the first(0.77±0.09)and second(0.77±0.10)measurements(P=0.53).There was no significant difference of averaged vessel density(%)between the first(6.11±1.39)and second(6.12±1.40)measurements(P=0.85).Conclusions:Quantitative analysis of the retinal vasculature was feasible in fundus photos taken using the PanOptic ophthalmoscope.The device appears to provide sufficient image quality for analyzing A/V ratio and vessel density with the benefit of portability,easy data transferring,and low cost of the device,which could be used for pre-clinical screening of systemic,cerebral and ocular diseases.