Evidence-based Canadian guidelines for tele-retina screening for diabetic retinopathy: recommendations from the Canadian Retina Research Network (CR2N) Tele-Retina Steering Committee M.C. Boucher,* J. Qian, y,z M.H. Brent, z,x D.T. Wong, z,║ T. Sheidow, { R. Duval,* A. Kherani,** R. Dookeran, yy D. Maberley, zz A. Samad, xx V. Chaudhary y Steering Committee for Tele-Ophthalmology Screening, Canadian Retina Research Network ABSTRACT  Objective: The purpose of this report is to develop a consensus for Canadian national guidelines specific to a tele-medicine approach to screening for diabetic retinopathy (DR) using evidence-based and clinical data. Methods: Canadian Tele-Screening Grading Scales for DR and diabetic macular edema (DME) were created primarily based on severity grading scales outlined by the International Clinical Diabetic Retinopathy Disease Severity Scale (ICDR) and the Scottish DR Grading Scheme 2007. Other grading scales used in international screening programs and the clinical expertise of the Canadian Retina Research Network members and retina specialists nationwide were also used in the creation of the guidelines. Results: National Tele-Screening Guidelines for DR and DME with and without optical coherence tomography (OCT) images are pro- posed. These outline a diagnosis and management algorithm for patients presenting with different stages of DR and/or DME. General guidelines detailing the requirements for imaged retina fields, image quality, quality control, and follow-up care and the role of visual acuity, pupil dilation, OCT, ultra-wide-field imaging, and artificial intelligence are discussed. Conclusions: Tele-retina screening can help to address the need for timely and effective screening for DR, whose prevalence continues to rise. A standardized and evidence-based national approach to DR tele-screening has been proposed, based on DR/DME grading using two 45° image fields or a single widefield or ultra-wide-field image, preferable use of OCT imaging, and a focus on local quality control measures. In 2018, the estimated prevalence of diagnosed diabetes in Canada was approximately 3.6 million Canadians, or 9% of the population. According to Diabetes Canada, this is expected to increase to affect approximately 4.7 million or 11% of the Canadian population by 2028. 1 Diabetic retinop- athy (DR), a complication of diabetes, is the most common cause of legal blindness in the working-age population and the leading cause of visual impairment in Canada. 24 Although treatments are available for sight-threatening DR, this requires effective screening strategies for follow-up and management. With the increasing prevalence of DR and advances in ophthalmic imaging technologies, tele-ophthal- mology initiatives are being increasingly used in Canada and worldwide to identify and triage patients with DR. 5 How- ever, successful DR screening, especially as it relates to tele- medicine that may be employed on a more widespread scale, requires adherence to consistent guidelines for retinal imag- ing, grading DR severity, and recommendations for referral. At the moment, there are no national guidelines for DR tele-screening and grading in Canada. Implementation of such guidelines would provide quality assurance and enable consis- tent comparison and analysis of data for optimal patient management. The Canadian Retina Research Network (CR2N) struck a steering committee with retinal experts across Canada in 2019 to develop consensus guidelines on the topic of tele-retinal screening for DR using evidence-based and clini- cal data. These guidelines comprise the key recommendations from that working group and are endorsed by the CR2N. The appropriateness of these guidelines will be assessed at regular intervals and revised as programs grow, new technologies emerge, and other updates become available. TAGGEDH1GENERAL GUIDELINESTAGGEDEND Inclusion and Exclusion Criteria for DR Tele-Screening Inclusion criteria  Patients 12 years old with type 2 diabetes  Exclusion criteria  Pregnancy: information about pregnancy may not be con- sistently transmitted to or seen by the readers with conse- quent risk of inadequate follow-up and recommended management in pregnant diabetics with DR. © 2020 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved. https://doi.org/10.1016/j.jcjo.2020.01.001 ISSN 0008-4182 14 CAN J OPHTHALMOL—VOL. 55, NO. 1S1, FEBRUARY 2020