Comparing image quality and trachoma detection across three camera types from a survey in Kongwa, Tanzania
- Int Health. 2023 Dec 4;15(15 Suppl 2):ii19-ii24. doi: 10.1093/inthealth/ihad054.
- 1. Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- 2. Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University Hospital, 600 N. Wolfe St., Baltimore, MD 21287, USA.
- 3. Kongwa Trachoma Project, Kongwa, Tanzania.
- 4. Robert Larner College of Medicine, University of Vermont School of Medicine, 111 Colchester Ave, Burlington, VT 05401, USA.
Background: There is an increasing demand for photography for trachoma prevalence surveys. In previous studies, digital single lens reflex (DSLR) images were superior to smartphone images, but newer-model smartphones and/or lens attachments may be able to bridge this gap. This study compares the image quality and ability to detect trachomatous inflammation - follicular (TF) of three camera types: a DSLR Nikon camera, an iPhone SE and an iPhone 13 Pro with a cell scope.
Methods: We surveyed 62 children ages 1-7 y from two Tanzanian communities. Upper tarsal conjunctiva images of both eyes were graded for TF by two standardized graders. The McNemar's test and a logistic regression model were used for analyses.
Results: The DSLR camera malfunctioned during the study, thus the iPhone SE and iPhone 13 Pro with cell scope were both more likely to take high-quality, gradable photographs (88% and 86%, respectively) compared with the DSLR camera (69%) (p<0.001 and p=0.02, respectively). TF was detected in gradable images from the iPhone SE (8.8%) and iPhone 13 Pro with cell scope (9.0%) at the same rate (p=1.0) as images from the DSLR camera (9.7%).
Conclusion: Smartphones with high-quality image capture, like the iPhone SE/13 Pro, have the potential for use in trachoma surveys if the proportion of gradable images can be improved.