Diabetic eye disease: Where are we now?

Diabetes is still one of the fastest growing global health emergencies of the 21st century. It was estimated that 537 million people had diabetes in 2021. This number is projected to reach 643 million by 2030, and 783 million by 2045. Common and specific microvascular complications of diabetes, such as diabetic retinopathy and maculopathy, remain the leading causes of preventable blindness in working-aged people (Figures A and B). Today, there are still questions to be answered to prevent moderate and severe visual impairment (MSVI) and blindness caused by diabetic eye disease.

Prevalence of Blindness and Moderate and Severe Visual Impairment Due to Diabetic Eye Complications (A)

Which method should we choose to detect and evaluate the anatomical and functional aspect of diabetic retinopathy, and decide on the best treatment? How far have we progressed in the detection and treatment of diabetic retinopathy since the Liverpool declaration? Given the increase in the number of patients with diabetes, do we need to adapt the frequency of visits and include other pathologies in screenings?

Prevalence of Blindness and Moderate and Severe Visual Impairment Due to Diabetic Eye Complications (B)

Where are we now? Are we addressing the concerns of society and our patients?

In a panel discussion at the 2024 European Society of Retina Specialists Congress, experts from the European Association for the Study of Diabetic Eye Complications (EAsDEC) addressed these tough questions. As co-chairs of the special World Retina Day symposium, we have assembled highlights from the panel discussion, which illustrate the current outlook of diabetic eye disease and what EAsDEC members forecast in years to come.

Colour imaging and laser treatment have a role to play

In her lecture, Caroline Styles, consultant ophthalmologist, NHS Fife, Scotland, considered more well-established imaging and treatment techniques. In her lecture, she addressed colour imaging and laser treatments, and whether they are still relevant in 2024 for managing diabetic eye disease. Dr Styles talked about the role of colour fundus photographs in screening programmes, concluding that the standard macula and disc centred images were still relevant for screening for diabetic eye disease in 2024. The widefield field imaging is very useful for virtual clinics, diagnosing the level of diabetic eye disease and looking at response to panretinal photocoagulation laser treatment. Anti-vascular endothelial growth factor (VEGF) therapies are often pitted against laser treatment as a potential alternative. Dr Styles presented the recent National Institute for Clinical Excellence (NICE) guidelines, which recommend laser for proliferative diabetic retinopathy as first-line treatment, with anti-VEGF deployed in some cases with an inadequate response. Per the NICE guidelines, anti-VEGF agents are recommended if these conditions are met: best-corrected visual acuity is between 6/12 and 6/96; there is no permanent structural damage to the central fovea; the lesion size is 12 disc areas or less in greatest linear dimension; and there imaging shows evidence of recent disease progression. Dr Styles also noted that laser treatment remains relevant for the treatment of diabetic macular oedema if there is no anti-VEGF service in low- and middle-income countries.

Recontextualising functional outcomes to understand diabetic retinopathy

In her presentation, Stela Vujosevic, MD, PhD, FEBO, FARVO, advocated for a renewed focus on functional outcomes to better understand the progression of diabetic retinopathy (DR) therapies. DR involves neural damage, often before symptoms appear. Hyperglycaemia disrupts retinal cell interactions, reducing functionality and visual performance. Thus, accessible early visual function parameters are needed to monitor disease progression, predict severe vision loss risk, assess treatment effectiveness and understand how patients’ experiences affect their quality of life. Each visual function test has strengths but lacks specificity when used alone, and non-DR factors may influence measurements. A structural-function approach is crucial for monitoring the disease, especially the impact of new treatments, Prof Vujosevic said. Artificial intelligence (AI) presents opportunities to transform the management of DR and diabetic macular oedema, equipping health care professionals with practical tools and enhancing patient functional results. In the end, the ultimate goal of patient care, from the patients’ perspective, is to achieve a better functional outcome, and comprehensive screenings can make this best-case scenario a reality.

Annual screenings: Assessing their necessity

The delivery of diabetic retinal screening globally has greatly improved the outcomes for patients affected by diabetes with respect to their vision and retinopathy. In his presentation, David Keegan, FRCSI(Oph), FRCOphth, PhD, discussed the Irish diabetic screening programme. Mr Keegan is national clinical lead for the programme.

He noted that, among the patients within the programme, there were a number of low-risk patients that could potentially move to extended interval screening. Following extensive literature review and consultation with stakeholders, his team submitted that proposal to the National Screening Advisory Committee. Upon implementation of the extended-interval screening (every 2 years), they noted that this was a safe, effective way to deliver screening, with a minimal number of patients progressing to sight-threatening retinopathy over the 2-year period (0.45%). The progression rate to proliferative ret­inopathy was less than 0.1% over that period.

With an increasing strain on the delivery of screening services with the increased population of people with diabetes, the move to individualised screening or mass low-risk screening intervals such as this will provide a way to improve capacity and improve access to care for those most at need, Mr Keegan said.

The Irish National Diabetic Retinal Screening Programme identified an issue with the increased number of referrals for non-diabetic eye disease such as cataract, glaucoma and macular degeneration. This now comprises approximately 45% of all referrals to our treatment centres and risks swamping our treatment centres and interfering with the delivery of care to those with diabetic retinopathy. Through a consultation process, the Irish screening programme is reviewing its referral pathways for these, and looking to integrate cataract and glaucoma into a national referral programme pathway directly to eye units, and not specifically to diabetic eye disease treatment centres. This should further reduce the burden of care for non-diabetic eye disease, which is outside the scope of a diabetic retinal screening programme to those treatment centres.

Ali Erginay, MD | E: ali.erginay@aphp.fr

Erginay is a senior consultant ophthalmologist at Lariboisière Hospital, Paris, France.

Tunde Peto, MD, PhD | E: T.Peto@qub.ac.uk

Peto is a professor of clinical ophthalmology at the School of Medicine, Dentistry and Biomedical Sciences, Queen’s University Belfast, Ireland.