Teleretina screening for diabetic retinopathy
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* Daniel Rosenberg
* Jason Noble
* Varun Chaudhary

## Ophthalmic screening is essential for detection of diabetic retinopathy

Diabetes Canada recommends eye exams every 1–2 years upon diagnosis of type 2 diabetes.1 A systematic review found that an average of 175 (range 75–267) screening sessions are required to detect 1 case of sight-threatening diabetic retinopathy in patients without retinopathy at baseline.2

## Teleretina screening is a viable adjunct to in-person screening

Teleretina screening involves digital transmission of ocular images obtained by a technician for remote evaluation by a specialist (Appendix 1, available at [www.cmaj.ca/lookup/doi/10.1503/cmaj.202141/tab-related-content](http://www.cmaj.ca/lookup/doi/10.1503/cmaj.202141/tab-related-content)). Technicians typically require one-on-one training with a teleophthalmology expert to effectively capture images.3 High-level evidence shows > 95% sensitivity and specificity for detection of diabetic retinopathy using teleretina screening.1 Teleretina screening is associated with reduced costs relative to in-person assessment.3

## Patients with diabetes are more likely to participate in remote screening than in-person visits

A recent meta-analysis found significantly greater patient attendance for teleretina screening compared with traditional in-person assessment (odds ratio 13.15, 95% confidence interval 8.01–21.61, *p* < 0.001).4 Patients in poor health with limited access to health care professionals have challenges attending in-person screening; these patients are a target demographic for teleretina assessment.1

## Teleretina screening is not available or recommended for all patients

Current evidence-based guidelines for teleretina screening apply only to nonpregnant patients aged 12 years or older with type 2 diabetes.5 Occasionally, images obtained during telescreening may be deemed “ungradable,” requiring an in-person assessment.1 Conditions that may interfere with the digital photo acquisition include dense cataracts or corneal scars.6

## Centralized teleretina referral systems are in development in Canada

Several teleretina clinics have been initiated across Canada.1 Primary care providers are encouraged to contact the Canadian Retina Society ([www.crssrc.ca](http://www.crssrc.ca)) for further information and guidance on referral to telescreening programs.

## Footnotes

*   **Competing interests:** Jason Noble serves on the advisory board for Novartis and Bayer and is a speaker for Novartis. Varun Chaudhary has served on the advisory board and as a consultant for Novartis, Bayer and Roche, and has investigator-sponsored research grants and participates in clinical trials funded by Novartis, Bayer and Allergan. All of these competing interests are outside the submitted work. No other competing interests were declared.

*   This article has been peer reviewed.

This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY-NC-ND 4.0) licence, which permits use, distribution and reproduction in any medium, provided that the original publication is properly cited, the use is noncommercial (i.e., research or educational use), and no modifications or adaptations are made. See: [https://creativecommons.org/licenses/by-nc-nd/4.0/](https://creativecommons.org/licenses/by-nc-nd/4.0/)

## References

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2.  Groeneveld Y, Tavenier D, Blom JW, et al. Incidence of sight-threatening diabetic retinopathy in people with type 2 diabetes mellitus and numbers needed to screen: a systematic review. Diabet Med 2019;36:1199–208.
    
    

3.  Kim J, Driver DD. Teleophthalmology for first nations clients at risk of diabetic retinopathy: a mixed methods evaluation. JMIR Med Inform 2015;3:e10.
    
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4.  Kawaguchi A, Sharafeldin N, Sundaram A, et al. Tele-ophthalmology for age-related macular degeneration and diabetic retinopathy screening: a systematic review and meta-analysis. Telemed J E Health 2018;24:301–8.
    
    

5.  Boucher MC, Qian J, Brent MH, et al.; Steering Committee for Tele-Ophthalmology Screening, Canadian Retina Research Network. Evidence-based Canadian guidelines for tele-retina screening for diabetic retinopathy: recommendations from the Canadian Retina Research Network (CR2N) Tele-Retina Steering Committee. Can J Ophthalmol 2020;55(Suppl 1):14–24.
    
    

6.  Silva PS, Horton MB, Clary D, et al. Identification of diabetic retinopathy and ungradable image rate with ultrawide field imaging in a national teleophthalmology program. Ophthalmology 2016;123:1360–7.
    
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