Tele-optometry for eye disease screening: a scoping review of context-dependent diagnostic performance and limitations for large-scale implementation

IntroductionVision impairment is disproportionately higher in low- and middle-income countries (LMICs). Tele-optometry has emerged as a promising approach to expanding access to primary eye care, particularly for screening and early detection of eye diseases. Existing evidence varies in study design, sample size, screening modalities, and accuracy metrics. This review aimed to map current evidence on the diagnostic accuracy and effectiveness of tele-optometry for eye disease screening in low-resource settings.MethodsA comprehensive search was conducted across PubMed, Scopus, Embase, Web of Science, Cochrane Library, African Journals Online, and grey literature. Titles, abstracts, and full texts were independently screened by all authors, with discrepancies resolved by consensus. Data extraction and quality assessment followed the PRISMA-ScR checklist and the Joanna Briggs Institute Checklist for Scoping Reviews. Findings were synthesized to generate an evidence map.ResultsSeventeen studies published between 2005 and 2025 were included, mostly prospective diagnostic accuracy studies in low-resource settings. Tele-optometry showed acceptable to high accuracy, particularly for diabetic retinopathy (DR) and refractive errors. For DR, sensitivities ranged from 88.7%–95% and specificities from 86%–96% (κ = 0.60–0.85). Specificity across conditions was consistently high (93.5%–99.8%), though sensitivity varied, with lower performance for glaucoma (as low as 12.5%) and higher for cataract (>90%). Studies ranged from ∼100 to 58,612 participants, concentrated in India and South Asia; many excluded complex cases, and few reported downstream outcomes.ConclusionTele-diagnostic screening shows promise for high-prevalence conditions with straightforward criteria, such as DR and refractive error, but is less reliable for complex diseases like glaucoma. These conclusions are constrained by limited downstream-outcome reporting and geographic concentration. Policymakers should prioritize validated applications and avoid premature scale-up to safeguard patient safety.