Experts at Edinburgh University said the technology could support early diagnosis of kidney disease as current screening tests cannot detect the condition until half of the kidney function has been lost. The team’s findings are detailed in Nature Communications.
Researchers used highly magnified images to detect changes to the retina and found that the images offer a quick, non-invasive way to monitor kidney health.
In a statement, Dr Aisling McMahon, executive director of research and policy at Kidney Research UK, said: “Kidney patients often face invasive procedures to monitor their kidney health, often on top of receiving gruelling treatments like dialysis.
“This fantastic research shows the potential for a far kinder way of monitoring kidney health.”
The eye is the only part of the body where it is possible to view microvascular circulation, and this flow of blood through the body’s smallest vessels is often affected in kidney disease.
Researchers at Edinburgh University investigated whether 3D images of the retina, taken using optical coherence tomography (OCT), could be used to identify and accurately predict the progression of kidney disease.
OCT scanners use light waves to create a cross-sectional picture of the retina, displaying each individual layer.
The team looked at OCT images from 204 patients at different stages of kidney disease, including transplant patients, alongside 86 healthy volunteers.
They found that patients with chronic kidney disease had thinner retinas compared with healthy volunteers. The study also showed that thinning of the retina progressed as kidney function declined.
These changes were reversed when kidney function was restored following a successful transplant. Patients with the most severe form of the disease, who received a kidney transplant, experienced rapid thickening of their retinas after surgery.
With further research, regular eye checks could aid early detection and monitoring to prevent the disease from progressing.
The technology could also aid the development of new drugs, the research team said. It could do so by measuring changes in the retina that indicate whether – and in what way – the kidney responds to potential new treatments.
Dr Neeraj (Bean) Dhaun, Professor of Nephrology at Edinburgh University’s Centre for Cardiovascular Science, said: “We hope that this research, which shows that the eye is a useful window into the kidney, will help identify more people with early kidney disease – providing an opportunity to start treatments before it progresses.
“It also offers potential for new clinical trials and the development of drug treatments for a chronic disease that, so far, has proved extremely difficult to treat.”
The researchers said further studies – including longer-term clinical trials in larger groups of patients – are needed before the technology can be routinely used.
The research was funded by Kidney Research UK, and supported by Edinburgh Innovations, the University’s commercialisation service.