A Novel Device for Smartphone-Based Fundus Imaging and Documentation in Clinical Practice: Comparative Image Analysis Study

Abstract

Background Smartphone-based fundus imaging allows for mobile and inexpensive fundus examination with the potential to revolutionize eye care, particularly in lower-resource settings. However, most smartphone-based fundus imaging adapters convey image quality not comparable to conventional fundus imaging. Objective The purpose of this study was to evaluate a novel smartphone-based fundus imaging device for documentation of a variety of retinal/vitreous pathologies in a patient sample with wide refraction and age ranges. Methods Participants’ eyes were dilated and imaged with the iC2 funduscope (HEINE Optotechnik) using an Apple iPhone 6 in single-image acquisition (image resolution of 2448 × 3264 pixels) or video mode (1248 × 1664 pixels) and a subgroup of participants was also examined by conventional fundus imaging (Zeiss VISUCAM 500). Smartphone-based image quality was compared to conventional fundus imaging in terms of sharpness (focus), reflex artifacts, contrast, and illumination on semiquantitative scales. Results A total of 47 eyes from 32 participants (age: mean 62.3, SD 19.8 years; range 7-93; spherical equivalent: mean –0.78, SD 3.21 D; range: –7.88 to +7.0 D) were included in the study. Mean (SD) visual acuity (logMAR) was 0.48 (0.66; range 0-2.3); 30% (14/47) of the eyes were pseudophakic. Image quality was sufficient in all eyes irrespective of refraction. Images acquired with conventional fundus imaging were sharper and had less reflex artifacts, and there was no significant difference in contrast and illumination (P<.001, P=.03, and P=.10, respectively). When comparing image quality at the posterior pole, the mid periphery, and the far periphery, glare increased as images were acquired from a more peripheral part of the retina. Reflex artifacts were more frequent in pseudophakic eyes. Image acquisition was also possible in children. Documentation of deep optic nerve cups in video mode conveyed a mock 3D impression. Conclusions Image quality of conventional fundus imaging was superior to that of smartphone-based fundus imaging, although this novel smartphone-based fundus imaging device achieved image quality high enough to document various fundus pathologies including only subtle findings. High-quality smartphone-based fundus imaging might represent a mobile alternative for fundus documentation in clinical practice.

Learning curve evaluation upskilling retinal imaging using smartphones

“…Image quality achieved was comparable to a previous study with this SBFI device 31 . Both studies used the same image quality scales for reflex artifacts and contrast/illumination, whereas the other study used an extended scale for sharpness/focus developed for direct comparison with conventional color fundus imaging 31 . While overall image quality was comparable, reflex artifacts seemed less prevalent in this study.…”

“…The reason for this might be the much younger age of the participant sample and consequently the absence of pseudophakia. Pseudophakia is likely the main source of reflex artifacts for this SBFI device 31 .…”

“…An iPhone 6 (Apple Inc., Cupertino, California, USA) with the Heine iC2 (see Fig. 1 ) as a SBFI adapter were used in this study 31 . The SBFI adapter was unknown to all participants and was connected to the smartphone via Bluetooth and an application developed by the manufacturer of the device was installed on the mobile device in order to connect and operate the SBFI adapter.…”

The Role of Telemedicine, In-Home Testing and Artificial Intelligence to Alleviate an Increasingly Burdened Healthcare System: Diabetic Retinopathy

“…The quality of smartphone imaging is lower than that of conventional fundus imaging. More artifacts appeared in smartphone imaging when the mid- and far periphery of the retina was included in pseudophakic eyes [ 94 ]. The quality of images depends on the type of smartphone adapter, but not on the experience of the investigator [ 91 ].…”

“…The quality of images depends on the type of smartphone adapter, but not on the experience of the investigator [ 91 ]. It is possible to take a picture of the fundus without dilation of the pupil, but it is more time-consuming to obtain a clear image [ 94 ]. A picture of the optic disc and the macula can be taken without special adapters, after pupil dilation, using the 20D Volk lens in front of the patient’s eye [ 95 ].…”