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Comparison of true-colour wide-field confocal scanner imaging with standard fundus photography for diabetic retinopathy screening
  1. Abraham Olvera-Barrios1,2,
  2. Tjebo FC Heeren1,2,
  3. Konstantinos Balaskas1,
  4. Ryan Chambers3,
  5. Louis Bolter3,
  6. Adnan Tufail1,2,
  7. Catherine Egan1,2,
  8. John Anderson3
  1. 1Medical Retina, Moorfields Eye Hospital NHS Foundation Trust, London, UK, London, UK
  2. 2University College London Institute of Ophthalmology, London, UK
  3. 3Diabetes, Homerton University Hospital NHS Foundation Trust, London, UK
  1. Correspondence to Mr Abraham Olvera-Barrios, Moorfields Eye Hospital, London EC1V 2PD, UK; a.olvera{at}


Background Screening of diabetic retinopathy (DR) reduces blindness by early identification of retinopathy. This study compares DR grades derived from a two-field imaging protocol from two imaging platforms, one providing a single 60-degree horizontal field of view (FOV) and the other, a standard 45-degree FOV.

Methods Cross-sectional study which included 1257 diabetic patients aged ≥18 years attending their DR screening visit in the English National Diabetic Eye Screening Programme (NDESP). Patients with maculopathy (M1), preproliferative (R2) or proliferative DR (R3) were referred to an ophthalmologist. Patients with ungradable images (U) are examined in a slit-lamp biomicroscopy clinic. Image acquisition under mydriasis of two images per eye was carried out with the EIDON and with standard fundus cameras. Evaluation was performed by masked graders.

Results Agreement after consensus with kappa statistic was 0.89 (quadratic weights (95% CI 0.87 to 0.92)) for NDESP severity grade, 0.88 (quadratic weights (95% CI 0.82 to 0.94)) for referable disease and 0.92 (linear weights (95% CI 0.88 to 0.95)) for maculopathy. The EIDON detected clinically relevant DR features outside the 45-degree fields in two patients (0.16%): one with intraretinal microvascular abnormalities (IRMAs) and one with neovascularisation. In eight patients (0.64%), the EIDON allowed DR feature visualisation inside the 45-degree fields that were not identified in the NDESP images: three patients (0.24%) with IRMA and five patients (0.40%) with maculopathy. The rates of ungradable encounters were 12 (0.95%) and 13 (1.03%) with the EIDON and NDESP images, respectively.

Conclusion The EIDON identifies a small number of additional patients with referable disease which are not detected with standard imaging. This is due to the EIDON finding disease outside the standard FOV and greater clarity finding disease within the standard FOV.

  • retina
  • public health
  • neovascularisation
  • epidemiology
  • diagnostic tests/investigation

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  • Contributors AOB and TH: statistical analysis, interpretation of data, manuscript preparation and manuscript approval. KB, RC and LB: acquisition of data, manuscript preparation and manuscript approval. AT, CE and JA: study conception and design, interpretation of data, manuscript preparation and manuscript approval.

  • Funding This work was funded by the North East London Diabetes Eye Screening Programme (RC, LB and JA). This research has received a proportion of its funding (salary support for AT and CE) from the Department of Health’s National Institute for Health Research Biomedical Research Centre for Ophthalmology at Moorfields Eye Hospital and UCL Institute of Ophthalmology, the Lowy Medical Research Institute (TH) and from the Department of Ophthalmology of the University Hospital, Universidad Autónoma de Nuevo León (AOB).

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval The study protocol was registered and approved through the research governance process at this clinical centre and adhered to the tenets of the Declaration of Helsinki and the UK Data Protection Act 2018.

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

  • Data availability statement The data that support the findings of this study are available from the North East London Diabetic Eye Screening Programme upon reasonable request.