Wide-field fundus camera using smartphone's macro-camera for Diabetic Retinopathy screening

Abstract

Diabetic Retinopathy (DR) is the first cause of blindness in working-age adults (20-74 years old), but if prompt diagnosis is made, 80% of DR complications can be delayed or prevented. Smartphone and wide-field fundus photography have been showing promising results for DR screening; however, efforts continue to get better fundus camera devices regarding image quality, FOV, affordability, and accessibility that could help prevent blindness through prompt diagnosis. Here we show the design, implementation, and characterization of a wide-field smartphone-based fundus camera prototype (TRL 4) to be used as a point-of-care device for DR screening. What stands our design apart is the use of a smartphone's macro-camera with a high diopter ophthalmic loupe for wide-field in a single shot, our cross-polarized ring for reflection-free fundus images, and the two-handed mechanical design to enhance stability. The presented prototype is safe (Group 1 according to ISO 15004-2), easy to use (80° static FOV), affordable (500 USD <), portable (hand-held, 280 x 90 x 90 mm and 410 gr), and reliable (46 lp/mm central spatial resolution at fundus). The prototype represents an ideal alternative for DR screening at point-of-care and, by incorporating the appropriate AI and teleophthalmology tools, a potential improvement in blindness prevention in the diabetic population.