Objectives: To examine how mydriasis and the medical qualifications of photographers who take retinal photographs influence the accuracy of screening for diabetic retinopathy (DR).
Methods: Our meta-analysis included studies that measured the sensitivity and specificity of tests designed to detect any DR, sight-threatening DR, or macular edema. Using random-effects logistic regression, we examined the effect of variations in mydriatic status and in medical qualifications of photographers on sensitivity and specificity.
Results: Only the category of "any DR" had sufficient consistency in definition, number of studies (n = 20), and number of assessments (n = 40) for meta-analysis. Variations in mydriatic status did not significantly influence sensitivity (odds ratio [OR], 0.89; 95% confidence interval [CI], 0.56-1.41; P = .61) or specificity (OR, 0.94; 95% CI, 0.57-1.54; P = .80). Variations in medical qualifications of photographers did not significantly influence sensitivity (OR, 1.25; 95% CI, 0.31-5.12; P = .75). Specificity of detection of any DR was significantly higher for screening methods that use a photographer with specialist medical or eye qualifications (OR, 3.86; 95% CI, 1.78-8.37; P = .001).
Conclusion: Outreach screening is an effective alternative to on-site specialist examination. It has potential to increase screening coverage of high-risk patients with DR in remote and resource-poor settings without the risk of missing DR and the opportunity to prevent vision loss. Our analysis was confined to the presence or absence of DR. Future studies should use consistent DR classification schemes to facilitate further analysis.