The damage in retinal periphery is a result of the loss of blood flow in diabetics, said a study conducted by Joslin Diabetes Center’s Beetham Eye Institute.
The study revealed that people with diabetic retinopathy, the presence of lesions in the periphery of their retina substantially increases the risk that the disease will progress more rapidly.
Not detected earlier, these peripheral lesions correlate very closely with the loss of retinal blood flow called retinal “non-perfusion” caused by loss of small blood vessels or capillaries, said the study.
The Joslin scientists used ultra-wide-field (UWF) imaging to examine the eyes of 37 patients with diabetes and varying levels of retinopathy ranging from no disease to very advanced disease. UWF retinal imaging can view more than 80 percent of the retina in a single image.
In comparison, traditional clinical retinal imaging combines seven smaller photos to cover about a third of the retina, says Paolo Silva, staff ophthalmologist and assistant chief of telemedicine at the Beetham Eye Institute.
“The most surprising result was how very closely associated these two areas seemed to be,” says Lloyd Paul Aiello, Director of the Beetham Institute, Professor of Ophthalmology at Harvard Medical School and senior author on the paper.
He says that discovery raises the possibility that clinicians might be able to use the peripheral lesions to estimate the extent and location of the non-perfusion damage and the risk of disease progression without necessarily resorting to UWF angiography in every case.
A related trial by the Diabetic Retinopathy Clinical Research Network, now underway, will follow more than 350 diabetes patients across the United States with UWF imaging for at least four years.
If this national study confirms the Joslin findings about the association of peripheral lesions with risks of disease progression, and the close match of these lesions with non-perfusion, the grading system for diabetic eye disease probably will be revised to incorporate these risk factors and imaging approaches, Aiello says.
The Joslin team is now analyzing another alternative approach to assess levels of retinal perfusion—detecting levels of oxygen in blood cells non-invasively by measuring their absorption of a certain wavelength of light.