Smartphone-based fundus imaging in global eye care: Closing the gap

Smartphone-based fundus imaging (SBFI) is an emerging approach with potential relevance for global ophthalmic care, including in low- and middle-income countries and other resource-constrained settings. This scoping review, based on a structured literature search, synthesizes current SBFI technology, clinical and teaching applications, implementation challenges and future directions. Analysing 30 hardware solutions (based on three principal technical designs) and 274 scientific publications and other relevant sources, we found that some SBFI devices can provide fields of view and image quality sufficient to support screening or triage for referable diabetic retinopathy, glaucoma-related optic nerve head changes, and selected retinopathy of prematurity applications. Reported sensitivity, specificity and gradability varied by disease, device, protocol, operator, and reference standard; no universal performance threshold could be inferred. After brief training, allied healthcare workers can acquire useable images in selected settings, suggesting that SBFI may support task-shifted screening and referral pathways. Artificial intelligence may further support scalability by assisting image-quality and protocol compliance assessment, frame selection, montage generation and disease classification. However, costs, maintenance requirements, data governance and domain shift remain important implementation considerations. Key challenges include variable image quality and fields of view, heterogeneous reporting, smartphone compatibility, regulatory compliance, photobiological safety verification, data security, and patient privacy. We therefore suggest minimum reporting standards to increase comparability across studies. Large-scale implementation and cost-effectiveness studies are needed to determine whether improved access to ophthalmic imaging can translate into sustainable and equitable eye-care services.