Hidden lesions predict the risk of sight loss from diabetic retinopathy
New 'wide-field' imaging can see more of the retina and reveal who is most at risk.
A new way to photograph the light-sensitive layer of the eye (the retina) may help predict which people with diabetic retinopathy are most at risk of sight loss.
Diabetic retinopathy is a major complication of diabetes. It’s one of the most common causes of sight loss in the UK amongst people of working age. Left untreated, it can lead to blindness.
Sight loss in diabetic retinopathy happens in the later stages of the condition. It’s due to the long-term effect of high blood sugar levels.
Over time, high blood sugar damages the blood vessels that bring oxygen and nutrients to the retina. This damage makes the blood vessel walls leaky. Eventually, unhealthy new blood vessels can grow and bleed. This can scar the retina or pull it away from its support layer of tissue.
Size does matter
Until now, a yearly standard set of photographs of the retina has been used to monitor the condition as it progresses. Together, these images cover about a third of the retina. But research from the USA published in the journal Ophthalmology shows that covering a wider area may be a better way to catch early damage to the retina.
The researchers used what’s known as an ‘ultrawide field camera’ in a study of 100 people with diabetes. This is a new type of camera that can take images of about 80 percent of the retina.
Study participants had also had retinal photos taken 4 years earlier. The aim then was to find out whether the new type of camera was as good at spotting diabetic retinopathy as standard imaging.
Results from that study showed that about 1 in 3 participants had lesions outside the centre of the retina. These ‘peripheral’ lesions made diabetic retinopathy worse for 1 in 10 participants.
Five times the risk
In the recent study, researchers followed-up the original participants. They found that eyes with lesions that were mostly outside the centre of the retina in the first study had three times the risk that diabetic retinopathy would get worse. The same eyes had almost five times the risk of developing the most advanced stage of the condition (‘proliferative diabetic retinopathy’).
Although the research team expected peripheral lesions to affect the progress of diabetic retinopathy, they were surprised by how much. They are now running a larger study of 350 people with diabetes over at least 4 years, to confirm their results.
Dr Dolores M Conroy is Fight for Sight’s Director of Research. She said: “One of the top priorities for research identified by the Sight Loss and Vision Priority Setting Partnership was to find out what factors predict progress to sight-threatening diabetic retinopathy.
Current methods focus on imaging the central retina, but wide-field retinal imaging is currently used in a few UK hospital eye services.
“Current methods focus on imaging the central retina, but wide-field retinal imaging is currently used in a few UK hospital eye services. It’s used in combination with optical coherence tomography (OCT) imaging, to increase accuracy in diagnosing sight-threatening diabetic retinopathy.”
The National Institute for Health Research is currently seeking funding applications for research projects to find out how well combining the new technology with OCT imaging works to monitor people with stable diabetic retinopathy.