Article Text

Evaluating the outcome of screening for glaucoma using colour fundus photography-based referral criteria in a teleophthalmology screening programme for diabetic retinopathy
  1. Rose Tan1,
  2. Kelvin Yi Chong Teo1,2,3,4,
  3. Rahat Husain1,3,
  4. Ngiap Chuan Tan5,
  5. Qian Xin Lee4,
  6. Haslina Hamzah4,
  7. Tina Wong1,3,
  8. Tin Aung1,3,
  9. Ching Yu Cheng1,3,6,
  10. Ecosse Luc Lamoureux1,3,
  11. Colin S Tan3,7,
  12. Hon-Tym Wong7,
  13. Tien Y Wong3,8,9,10,
  14. Gavin Siew Wei Tan1,3,4
  1. 1Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
  2. 2Save Sight Institute, Sydney, New South Wales, Australia
  3. 3Duke-NUS Medical School, National University of Singapore, Ophthalmology and Visual Sciences Academic Clinical Program, Singapore
  4. 4SNEC Ocular Reading Centre, Singapore National Eye Centre, Singapore
  5. 5Outram Polyclinic, SingHealth Polyclinics, Singapore
  6. 6Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
  7. 7Ophthalmology, Tan Tock Seng Hospital, National Healthcare Group Eye Institute, Singapore
  8. 8Singapore National Eye Centre & Singapore Eye Research Institute, Singapore
  9. 9Tsinghua Medicine, Tsinghua University, Beijing, People's Republic of China
  10. 10School of Clinical Medicine, Beijing Tsinghua Changgung Hospital, Beijing, People's Republic of China
  1. Correspondence to Dr Gavin Siew Wei Tan, Singapore Eye Research Institute, Singapore, Singapore; gavin.tan{at}


Aims To evaluate the effectiveness of glaucoma screening using glaucoma suspect (GS) referral criteria assessed on colour fundus photographs in Singapore’s Integrated Diabetic Retinopathy Programme (SiDRP).

Methods A case–control study. This study included diabetic subjects who were referred from SiDRP with and without GS between January 2017 and December 2018 and reviewed at Singapore National Eye Centre. The GS referral criteria were based on the presence of a vertical cup-to-disc ratio (VCDR) of ≥0.65 and other GS features. The final glaucoma diagnosis confirmed from electronic medical records was retrospectively matched with GS status. The sensitivity, specificity and positive predictive value (PPV) of the test were evaluated.

Results Of 5023 patients (2625 with GS and 2398 without GS) reviewed for glaucoma, 451 (9.0%, 95% CI 8.2% to 9.8%) were confirmed as glaucoma. The average follow-up time was 21.5±10.2 months. Using our current GS referral criteria, the sensitivity, specificity and PPV were 81.6% (95% CI 77.7% to 85.1%), 50.6% (95% CI 49.2% to 52.1%) and 14.0% (95% CI 13.4% to 14.7%), respectively, resulting in 2257 false positive cases. Increasing the VCDR cut-off for referral to ≥0.80, the specificity increased to 93.9% (95% CI 93.1% to 94.5%) but the sensitivity decreased to 11.3% (95% CI 8.5% to 14.6%), with a PPV of 15.4% (95% CI 12.0% to 19.4%).

Conclusions Opportunistic screening for glaucoma in a lower VCDR group could result in a high number of unnecessary referrals. If healthcare infrastructures are limited, targeting case findings on a larger VCDR group with high specificity will still be beneficial.

  • Glaucoma
  • Telemedicine
  • Diagnostic tests/Investigation
  • Public health

Data availability statement

Data are available on reasonable request.

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Data availability statement

Data are available on reasonable request.

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  • Contributors RT and GT researched and analysed data, contributed to discussion, wrote, reviewed and edited the manuscript. KYCT, RH, NCT, HH, TW, TA, CYC, ELL, CST and H-TW reviewed and edited the manuscript. QXL contributed to data cleaning and analysis. TYW served as the scientific advisor and reviewed the manuscript. All authors approved the final version of the manuscript. GT is the guarantor of this work and, as such, had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

  • Funding This study was supported by NMRC/TA/0055/2017, MOH-CSAINV21jun-005 and OFLCG/001/2017 from the Singapore National Medical Research Council (NMRC) and, the AIC/RPDD/SIDRP/SERI/FY2013/0018 (HSDP MOH) Funding for Singapore Integrated Diabetic Retinopathy Programme Roll-out, and MH 70:70/4-26 (MOH) Extension of SIDRP grant from Ministry of Health, Singapore.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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