An Affordable Smartphone-based Fundus Imaging Device for Retinal Examination.

Fundus imaging is widely used for diagnosing and monitoring ocular diseases such as diabetic retinopathy, glaucoma, and age-related macular degeneration. However, the high cost and limited availability of conventional fundus cameras pose significant barriers, particularly in resource-constrained settings. This study introduces the Glaucoma Screening on Phone (GSoP), an affordable and portable smartphone-based fundus imaging adapter designed to address these challenges. The adapter is developed using accessible and cost-effective components. We recorded retinal videos from dilated pupil with a focus on the optic disc region, which provides critical information on the degeneration of the optic nerve. While field testing revealed artifacts such as glare that reduced overall image quality, the GSoP demonstrated its ability to capture diagnostically relevant images of the optic disc region. A subjective qualitative comparison with the commercially available ophthalmoscope called oDocs-nun showed that although the GSoP's field of view is smaller, it effectively highlights the optic nerve head, a critical area for glaucoma screening. Our approach is well-suited for mydriatic video-based screening due to its limited field of view. With a production cost of under C10, the GSoP offers a practical and accessible solution for primary healthcare and educational purposes. Future improvements, including glare reduction mechanisms, AI-driven automation, and modular design options, have the potential to enhance its diagnostic capabilities and broaden its impact.