New research offers hope of revolutionising approaches to monitoring kidney health

05 December 2023

In a study, published in Nature Communications, researchers from the University of Edinburgh have shown that specialised eye scans using an imaging technology called optical coherence tomography (OCT) could be used to monitor kidney disease progression.

Seeking better ways to monitor kidney health

Kidney health is currently assessed by blood tests or invasive kidney biopsies (taking a small tissue sample), however, performing multiple biopsies over time to track any changes in kidney function can be unpleasant for patients and comes with some risk. We urgently need new, kinder ways to monitor disease progression or response to treatment and predict future health problems.

a black and white image of a specialised eye scan

An optical coherence tomography scan

Keeping an eye on kidney disease

The eye and the kidney are structurally similar, as are the pathways to disease, and so some diseases might present in a similar way in both organs. This enables researchers to gain important insights into kidney function by studying the eye. Using a fast and non-invasive imaging technology called OCT, which creates a detailed map of the eye’s layers, the Edinburgh team, led by Professors Neeraj Dhaun (Bean) and Matt Bailey, have shown that people with the spectrum of chronic kidney disease (CKD) have thinner retinas and choroid layers – structures at the back of the eye that play important roles in helping you see and keeping the eyes healthy.

With funding from Kidney Research UK and the British Heart Foundation, the Edinburgh team investigated whether measurements taken by OCT changed in line with changes in kidney function.

Eye measurements reflect changes in kidney function

The team compared eye scans from healthy volunteers with those from patients with different levels of kidney function and found that the eye measurements reflected these changes:

Compared with healthy volunteers, patients with CKD had thinner retina and choroid (or retinal and choroidal) layers, which became even thinner over time as their kidney function declined.
As early as one week after a kidney transplant, patients who had previously had kidney failure had thicker retina and choroid layers, which kept getting thicker for at least 12 months as their kidney function improved.
Conversely, researchers observed a gradual thinning of the retina and choroid layers in healthy individuals who donated a kidney during the year after their donation.

The team also showed that in patients with CKD, the thickness of the retina and choroid could be used to predict a future decline in kidney function.

With further funding from Kidney Research UK, the team are now working to understand the exact mechanisms that cause these eye changes to occur in line with kidney changes.

A kinder way to monitor kidney disease

Together, these results suggest that OCT measurements of the retina and choroid layers of the eye could be used as a non-invasive and sensitive way to monitor kidney disease progression and treatment response and might predict which patients may experience further health problems allowing doctors to intervene and treat them earlier.

An Asian man, earing a white shirt with a stethoscope

Professor Neeraj Dhaun

Bean, Professor of Nephrology at the University of Edinburgh’s Centre for Cardiovascular Science, said: “We hope in the future 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, thus far, has proved extremely difficult to treat.”

Dr Aisling McMahon, executive director of research and policy at Kidney Research UK added: “Kidney patients often face invasive procedures to monitor their kidney health, often on top of receiving gruelling treatments like dialysis. We are proud to have funded this fantastic research that shows the potential for a far kinder way of monitoring kidney health, and we are continuing to support the team as they investigate whether their approach could also be used to diagnose and intervene in kidney disease earlier.”