Teleophthalmology screening for diabetic retinopathy through mobile imaging units within Canada

Can J Ophthalmol. 2008 Dec;43(6):658-68. doi: 10.3129/i08-120.


Background: This study aimed to describe and measure the health results of a Category 3 teleophthalmology screening project for diabetic retinopathy (DR). Implemented through mobile screening imaging units located within pharmacies, the project had the goal of reaching unscreened diabetic patients in urban communities while lowering barriers to screening and saving medical resources.

Methods: Image capture of both eyes of 3505 known diabetic individuals was performed in the provinces of Quebec, British Columbia, Alberta, Manitoba, and Saskatchewan. A photographer performed fundus imaging, and a nurse used mild pupil dilation only when necessary to secure image quality. Screening was provided free of cost in the context of DR health days for DR screening. Through teleophthalmology, ophthalmologists proceeded with data and image interpretation, and timely referral when indicated.

Results: This project allowed the resumption of screening of over 38% of the cohort of known diabetics who reported never having undergone any eye examination with pupil dilation, and an additional 30% who reported not having been examined for over 2 years. All known diabetics were under the care of a general physician, and their mean diabetes duration, when known, was 8 years. DR pathology was found in 22.5% (20%-28%) of the cohort, 1.8% requiring urgent referral (within 30 days) as a result of the severity of the DR and 0.6% (0%-1.8%) requiring urgent referral for other reasons. An additional 8.7% (8.1%-19.5%) required ophthalmologic attention within 6 months because of DR and another 2.0% (0%-6.3%) between 6 months and 1 year. Incidental findings were found in 23%, the majority of which were related to cataract and dry macular degeneration. Urgent or significant incidental findings were found in 0.6% of the screened eyes. Pupil dilation with tropicamide 1% was deemed useful or necessary in 33.7% of the cohort. For 0.7% of the cohort, the images could not be interpreted because of poor image quality and for that reason had to be referred for a traditional dilated eye examination. Ophthalmologists were relieved of the examination of 85.6% of the screened diabetic individuals who benefited from screening without requiring a traditional ophthalmologic examination. On the other hand, ophthalmologists were required to provide urgent (within 30 days) services to 2% of the cohort, either because of threatening DR or because of incidental findings requiring rapid ophthalmologic attention.

Interpretation: This screening strategy for DR through mobile teleophthalmology imaging units efficiently lowered barriers to screening and created new screening opportunities for a large number of known diabetic individuals who were lost to the traditional health system. It has the potential to provide better outreach to diabetic populations while identifying individuals truly in need of the services of an ophthalmologist; at the same time it maximizes the use of limited ophthalmologic resources while favouring multidisciplinary collaborations. The significant incidental findings associated with screening highlight the need for ophthalmologic competencies during DR screening within a teleophthalmology approach. Further involvement of government health authorities is pivotal in embracing the opportunities provided by emerging technologies such as teleophthalmology and translating them into better outreach services to diabetic populations and thus better visual health results.

Publication types

  • Multicenter Study

MeSH terms

  • Aged
  • Canada
  • Diabetic Retinopathy / diagnosis*
  • Diagnostic Techniques, Ophthalmological*
  • Female
  • Humans
  • Image Processing, Computer-Assisted
  • Male
  • Middle Aged
  • Mobile Health Units
  • Ophthalmology / methods*
  • Remote Consultation / methods*
  • Telepathology / methods*
  • Urban Population