FEB 10, 2021
This is the first study to directly compare 4 different approaches for smartphone-based fundus imaging (SBFI) in terms of image quality and diagnostic accuracy for diabetic retinopathy (DR) screening.
Researchers recruited 193 patients (381 eyes) with diabetes at outreach eye clinics in southern India. They compared 4 technically different approaches of SBFI: 3 were based on direct ophthalmoscopy and 1 was based on indirect ophthalmoscopy. The main outcomes—image quality, field-of-view, examination time and diagnostic accuracy for DR screening—were analyzed against conventional fundus photography and clinical examination.
Imaging based on indirect ophthalmoscopy led to the best image quality, the largest field-of-view and the longest examination time (111 vs. 68–86 seconds). Compared with the 3 direct approaches, indirect SBFI had the highest level of agreement with the reference standard and sensitivity/specificity to detect DR (0.79/0.99 for any DR and 1.0/1.0 for severe DR, 0.79/1.0 for diabetic maculopathy).
The limitations of the study included a low prevalence of more severe diabetic retinopathy. The researchers could not assess the diagnostic accuracy.
Smartphone-based fundus imaging can meet DR screening requirements in an outreach setting and might alleviate some of the burden of DR screening in low- and middle-income countries. These results will help better select SBFI devices in field trials for DR screening.