Optics and Utility of Low-Cost Smartphone-Based Portable Digital Fundus Camera System for Screening of Retinal Diseases

Abstract

Purpose: To describe optical principles and utility of inexpensive, portable, non-contact digital smartphone-based camera for the acquisition of fundus photographs for the evaluation of retinal disorders. Methods: The digital camera has a high-quality glass 25 D condensing lens attached to a 21.4-megapixel smartphone camera. The white-emitting LED light of the smartphone at low illumination levels is used to visualize the fundus and limit source reflection. The camera captures a high-definition fundus (5344 × 4016) image on a complementary metal oxide semiconductor (CMO) with an area of 6.3 mm × 4.5 mm. The auto-acquisition mode of the device facilitates the quick capture of the image from continuous video streaming in a fraction of a second. Results: This new smartphone-based camera provides high-resolution digital images of the retina (50° telescopic view) in patients at a fraction of the cost (USD 1000) of established, non-transportable, office-based fundus photography systems. Conclusions: The portable user-friendly smartphone-based digital camera is a useful alternative for the acquisition of fundus photographs and provides a tool for screening retinal diseases in various clinical settings such as primary care clinics or emergency rooms. The ease of acquisition of photographs from a continuously streaming video of fundus obviates the need for a skilled photographer.

Using a smartphone‐based digital fundus camera for screening of retinal and optic nerve diseases in veterinary medicine: A preliminary investigation

“…Chalam et al. showed that fundic images captured with the Volk iNview (i.e., an older version of the Volk camera used in the current work) were also comparable with those acquired simultaneously with a traditional fundus camera 15 …”

“…14 Chalam et al showed that fundic images captured with the Volk iNview (i.e., an older version of the Volk camera used in the current work) were also comparable with those acquired simultaneously with a traditional fundus camera. 15 Smartphone-based fundus imaging has tremendous potential to revive the 'dying art' of ocular fundoscopy. 3 Similar to human physicians, 3 veterinarians and veterinary students often lack confidence in ophthalmoscopy, not only in the technical skill but also in the ability to interpret findings and detect potential abnormalities.…”

Fluorescence-Based Portable Assays for Detection of Biological and Chemical Analytes

“…The microfluidic chips can also be used for filtration and sample purification, which can result in higher accuracy [129,161,162]. Another crucial challenge at present is the miniaturization of these assay platforms and detection systems in order to expand their utility, particularly with regard to wearable devices (band, rings, patches, watches, glasses, shoes) [163][164][165][166][167]. Presently, wearable devices are very popular, as they make it possible to monitor a person's vitals in real time [168,169].…”

Clinical and Translational Imaging and Sensing of Diabetic Microangiopathy: A Narrative Review

“…For example, in [ 43 ], the authors employ a white light-emitting diode (LED) confocal device instead of the traditional fundus camera to overcome the frequent red-channel oversaturation. In another study [ 44 ], a simple smartphone camera (21.4-megapixel) is shown to be a useful alternative to conventional fundus camera equipment, increasing portability, ease of use, and dissemination. Furthermore, in [ 45 ], a red–green–blue (RGB) imaging regime is employed to extract label-free information about the oxygen saturation (SO 2 ) and hemoglobin concentration in the fundus, an option that could facilitate early detection of disease.…”