Accuracy of trained rural ophthalmologists versus non-medical image graders in the diagnosis of diabetic retinopathy in rural China

Martha McKenna, Tingting Chen, Helen McAneney, Miguel Angel Vázquez Membrillo, Ling Jin, Wei Xiao, Tunde Peto, Mingguang He, Ruth Hogg, Nathan Congdon

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20 Citations (Scopus)


BACKGROUND/AIMS: To determine the diagnostic accuracy of trained rural ophthalmologists and non-medical image graders in the assessment of diabetic retinopathy (DR) in rural China.

METHODS: Consecutive patients with diabetes mellitus were examined from January 2014 to December 2015 at 10 county-level facilities in rural Southern China. Trained rural ophthalmologists performed a complete eye examination, recording diagnoses using the UK National Diabetic Eye Screening Programme (NDESP) classification system. Two field, mydriatic, 45° digital photographs were made by nurses using NDESP protocols and graded by trained graders with no medical background using the NDESP system. A fellowship-trained retina specialist graded all images in masked fashion and served as reference standard.

RESULTS: Altogether, 375 participants (mean age 60±10 years, 48% men) were examined and 1277 images were graded. Grader sensitivity (0.82-0.94 (median 0.88)) and specificity (0.91-0.99 (median 0.98)), reached or exceeded NDESP standards (sensitivity 80%, specificity 95%) in all domains except specificity detecting any DR. Rural ophthalmologists' sensitivity was 0.65-0.95 (median 0.66) and specificity 0.59-0.95 (median 0.91). There was strong agreement between graders and the reference standard (kappa=0.84-0.87, p<0.001) and weak to moderate agreement between rural doctors and the reference (kappa=0.48-0.64, p<0.001).

CONCLUSION: This is the first study of diagnostic accuracy in DR grading among non-medical graders or ophthalmologists in low-income and middle-income countries. Non-medical graders can achieve high levels of accuracy, whereas accuracy of trained rural ophthalmologists is not optimal.

Original languageEnglish
Pages (from-to)1471-1476
Number of pages6
Issue number11
Publication statusPublished (in print/issue) - Nov 2018

Bibliographical note

© Author(s) (or their employer(s)) 2018. No commercial re-use. See rights and permissions. Published by BMJ.


  • Adult
  • China
  • Diabetic Retinopathy/diagnosis
  • Diagnosis, Computer-Assisted/standards
  • Education, Medical
  • Female
  • Humans
  • Image Interpretation, Computer-Assisted/standards
  • Male
  • Ophthalmologists/standards
  • Photography/classification
  • Preceptorship
  • Predictive Value of Tests
  • Reference Standards
  • Reproducibility of Results
  • Rural Nursing/standards
  • Rural Population
  • Sensitivity and Specificity


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