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

Abstract

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.

Enhancing Accessibility in Retinal Imaging through the Universal Smartphone Adapter

“…However, the study by [28] involving eight medical students have provided statistical analysis that shows the PanOptic ophthalmoscope is preferred over the conventional ophthalmoscope for the 'ease-of-use' despite the quality of image acquired were much poorer. The study by [27] have used the PanOptic ophthalmoscope together with a slip-lamp translator and a rest system for patient's chin and head which greatly improves stability but caused increment in the cost overall. In addition, the study by [27] have also stated that the software in the iExaminer application caused the resolution of fundus images acquired is low.…”

“…The study by [27] have used the PanOptic ophthalmoscope together with a slip-lamp translator and a rest system for patient's chin and head which greatly improves stability but caused increment in the cost overall. In addition, the study by [27] have also stated that the software in the iExaminer application caused the resolution of fundus images acquired is low. The iExaminer application also captures images by selecting stills from video recorded which also lowers the quality image taken.…”

The significance of teleophthalmology during a pandemic and in general

“…Another alternative to retinal imaging includes special smartphone applications, for instance, iExaminer (Welch Allyn, USA) designed for iPhone [17].…”

Smartphone-enabled retinal arteriovenous imaging and correlation with coronary SYNTAX score

“… 11 , 12 , 13 , 14 Smartphone technology is rapidly evolving and has gained widespread acceptance for performing point-of-care evaluation of retinal diseases such as retinopathy of prematurity and diabetes. 15 , 16 , 17 There have been sporadic case reports of the use of hand-held smartphone devices in conjunction with an ophthalmoscope for fundus AV ratio assessment, 18 , 19 but it has not been systematically evaluated for CAD risk assessment. We performed a study to assess the feasibility of retinal AV imaging using a smartphone and compared the results with conventional fundus camera-based images and the extent of coronary artery disease on angiography.…”