A simple eye test that predicts death from cardiovascular disease has been developed by British scientists.
It combines artificial intelligence (AI) with scans of the retina, the membrane at the back of the eye that contains light-sensitive cells.
The technique could lead to a screening programme enabling drugs and lifestyle changes to be prescribed decades before symptoms emerge.
Lead author, Professor Alicja Regina Rudnicka, of St George’s University of London, said the test is inexpensive, accessible and non-invasive.
People at risk of stroke, heart attack and other circulatory conditions could undergo artificial intelligence-enabled retinal vasculometry (RV) during routine visits to the optician.
Prof Rudnicka said: “It has the potential for reaching a higher proportion of the population in the community because of ‘high street’ availability.
“RV offers an alternative predictive biomarker to traditional risk scores for vascular health without the need for blood sampling or blood pressure measurement.
“It is highly likely to help prolong disease-free status in an ever-ageing population with increasing comorbidities, and assist with minimising healthcare costs associated with lifelong vascular diseases.”
An algorithm called Quartz was developed based on retinal images from tens of thousands of Britons aged 40 to 69.
It focused on the width, area and curvature, or tortuosity, of tiny blood vessels called arterioles and venules.
The performance of Quartz was compared with the widely used Framingham Risk Scores framework, both separately and jointly.
The health of all the participants was tracked for an average of seven to nine years, during which time there were 327 and 201 circulatory disease deaths among 64,144 UK Biobank and 5,862 EPIC-Norfolk participants respectively.
In men, arteriolar and venular width, tortuosity, and width variation emerged as important predictors of death from circulatory disease.
In women, arteriolar and venular area and width and venular tortuosity and width variation contributed to risk prediction.
The predictive impact of retinal vasculature on circulatory disease death interacted with smoking, drugs to treat high blood pressure, and previous heart attack.
Overall, these predictive models, based on age, smoking, medical history and retinal vasculature, captured between half and two-thirds of circulatory disease deaths in those most at risk.
And retinal vasculature models captured about 5 per cent more cases of stroke in UK Biobank men and 8 per cent more cases in UK Biobank women and 3 per cent more cases among EPIC-Norfolk men most at risk, but nearly 2 per cent fewer cases among EPIC-Norfolk women.
And Framingham Risk Scores captured more cases of heart attack among those most at risk.
Retinal imaging is already common practice in the UK and the US, point out the researchers.
Prof Rudnicka said: “Retinal vasculature is a microvascular marker, hence offers better prediction for circulatory mortality and stroke compared with heart attack which is more macrovascular, except perhaps in women.
“In the general population it could be used as a non-contact form of systemic vascular health check, to triage those at medium-high risk of circulatory mortality for further clinical risk assessment and appropriate intervention.”
In the UK, for example, it could be included in the primary care NHS Health Check for those aged between 41 and 74, they suggest.
Dr Ify Mordi and Dr Emanuele Trucco, of the University of Dundee, who were not involved in the study, said the use of retinal vasculature changes to inform overall cardiovascular risk is “certainly attractive and intuitive.”
They said: “Using retinal screening in this way would presumably require a significant increase in the number of ophthalmologists or otherwise trained assessors.
“What is now needed is for ophthalmologists, cardiologists, primary care physicians and computer scientists to work together to design studies to determine whether using this information improves clinical outcome, and, if so, to work with regulatory bodies, scientific societies and healthcare systems to optimise clinical workflows and enable practical implementation in routine practice.”
The study is in the British Journal of Ophthalmology.