Diagnostic test accuracy of diabetic retinopathy screening by physician graders using a hand-held non-mydriatic retinal camera at a tertiary level medical clinic

Mapa Mudiyanselage Prabhath Nishantha Piyasena*, Jennifer L.Y. Yip, David MacLeod, Min Kim, Venkata S.Murthy Gudlavalleti

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

Background: The evidence on diagnostic test accuracy (DTA) of diabetic retinopathy (DR) screening utilising photographic studies by non-ophthalmologist personnel in low and middle-income country (LMIC) settings is scarce. We aimed to assess DTA of DR screening using a nonmydriatic hand-held digital camera by trained general physicians in a non-ophthalmic setting. Methods: This study is a validation of a screening intervention. We selected 700 people with diabetes (PwDM) > 18 years of age, not previously screened or treated for DR, presenting at a tertiary medical clinic in Sri Lanka. Two-field retinal imaging was used to capture fundus images before and after pupil dilatation, using a hand-held non-mydriatic (Visuscout 100®-Germany) digital retinal camera. The images were captured and graded by two trained, masked independent physician graders. The DTA of different levels of DR was assessed comparing physician's grading with a retinologist's clinical examination by mydriatic bio-microscopy, according to a locally adopted guideline. Results: Seven hundred eligible PwDM were screened by physician graders. The mean age of participants was 60.8 years (SD ±10.08) and mean duration of DM was 9.9 years (SD ±8.09). Ungradable image proportion in non-mydriatic imaging was 43.4% (either eye-31.3%, both eyes 12.1%). This decreased to 12.8% (either eye-11.6%, both eyes-1.2%) following pupil dilatation. In comparison to detection of any level of DR, a referable level DR (moderate non-proliferative DR and levels above) showed a higher level of DTA. The sensitivity of the defined referable DR was 88.7% (95% CI 81.7-93.8%) for grader 1 (positive predictive value [PPV] 59.1%) and 92.5% (95% CI 86.4-96.5%) for grader 2 (PPV 68%), using mydriatic imaging, after including ungradable images as screen positives. The specificity was 94.9% (95% CI 93.6-96.0%) for grader 1 (negative predictive value [NPV] 99%) and 96.4% (95% CI 95.3-97.3%) for grader 2 (NPV 99.4%). Conclusions: The Physicians grading of images from a digital hand-held non-mydriatic camera at a medical clinic, with dilatation of pupil of those who have ungradable images, provides a valid modality to identify referable level of DR. This could be a feasible alternative modality to the existing opportunistic screening to improve the access and coverage. Trial registration: Current Controlled Trials ISRCTN47559703. Date of Registration 18th March 2019, Retrospectively registered.

Original languageEnglish
Article number89
JournalBMC Ophthalmology
Volume19
Issue number1
DOIs
Publication statusPublished - 8 Apr 2019
Externally publishedYes

Bibliographical note

Funding Information:
This study was funded by a PhD student project grant awarded to MMPNP, by Queen Elizabeth Diamond Jubilee Trust, coordinated through the Commonwealth Eye Health Consortium - United Kingdom. Funding and coordinating bodies had no role in the design of the study and collection, analysis and interpretation of data and in manuscript preparation.

Publisher Copyright:
© 2019 The Author(s).

Keywords

  • Diabetes
  • Diabetic retinopathy
  • Diagnostic accuracy
  • Digital imaging
  • Screening

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