<p>The Evolution of Diabetic Retinopathy Screening Programmes: A Chronology of Retinal Photography from 35 mm Slides to Artificial Intelligence</p>

Abstract

As a third of people with diabetes mellitus (DM) will suffer the microvascular complications of diabetic retinopathy (DR) and therapeutic options can effectively prevent visual impairment, systematic screening has substantially reduced disease burden in developed countries. In an effort to tackle the rising incidence of DM, screening programmes have modernized in synchrony with technical and infrastructural advancements. Patient evaluation has shifted from face-to-face ophthalmologist-based review delivered through community grassroots to asynchronous store-and-forward modern telemedicine platforms commissioned on a nationwide scale. First pioneered with primitive 35-mm slide film retinal photography, the last decade has seen an emergence of high resolution and widefield imaging devices, which may reveal extents of DR indiscernible to the clinician but with implications of potential earlier identification. Similar progress has been seen in image analysis approachesautomated image analysis of retinal photographs of DR has evolved from qualitative feature detection to rules-based algorithms to autonomous artificial intelligence-powered classification. Such models have, relatively rapidly, been validated and are now receiving approval from health regulation authorities with deployment into the clinical sphere. In this review, we chart the evolution of global DR screening programmes since their inception highlighting major milestones in healthcare infrastructure, telemedicine approaches and imaging devices that have shaped the robust and effective frameworks recognised today. We also provide an outlook for the future of DR screening in the context of recent technological advancements with respect to their limitations in current times.

Diabetic Retinopathy Screening and Registration in Europe—Narrative Review

“…The United Kingdom is the largest country in Europe with nationwide screening for all patients with DM above the age of 12 years. Screening started in 2003, reaching national coverage in 2008 [ 30 ]. The Health Improvement Network (THIN) database was created for the whole UK territory [ 31 ].…”

Utility of a smartphone assisted direct ophthalmoscope camera for a general practitioner in screening of diabetic retinopathy at a primary health care center

“…Teleophthalmological programs for DR screening have been adopted across the world for their cost-effectiveness and improved population coverage since their inception almost three decades back. [ 11 ] Smartphone-based fundus imaging has evolved from tandem use of a handheld smartphone camera and light source with a condensing 20D lens creating an indirect ophthalmoscope-like setup to clip-on lens attachments that provide a highly magnified and erect direct ophthalmoscope-like system using the smartphone's inbuilt light source as a coaxial beam of light. [ 16 ]…”

“…[ 9 ] Various models for teleophthalmological DR screening techniques have evolved, from conventional stereoscopic 7-field retinal imaging to single-field or double-field photography and more recently to smartphone-based fundus cameras. [ 10 11 12 13 ] This has made the process more affordable and universally accessible and has obviated the need for trained personnel to capture the images. Some of these devices have drawbacks, such as limited field of view, poor image quality, and restricted compatibility of the camera adaptors with particular models of smartphones.…”

A Mobile Tele-Ophthalmology System for Planned and Opportunistic Screening of Diabetic Retinopathy in Primary Care

“…The camera operators undergo days of training (e.g., 2 in [18]) prior to using the camera in the field. Examples of national screening programmes include the EyePACS (United States), the NHS DESP (United Kingdom), SiDRP (Singapore), OPHDIAT (France), and the Rastreio de Retinopatia Diabética (Portugal) [6], [19].…”