Adaptive Optics Detect Early Diabetes Eye Damage

Vision loss is a threat for millions of those suffering from diabetes. The earlier it can be detected, the sooner and potentially more effectively it can be treated.

Researchers from Indiana University have developed a new technique and instrument for detecting early warning signs of diabetic retinopathy, with the promise of enhanced diagnosis and better treatment.

A retinal capillary with multiple loops. The blood cannot travel directly to nourish the retinal cells. Courtesy of the Indiana University School of Optometry.

The instrument, designed by Stephen Burns, a professor and associate dean at the IU School of Optometry, takes advantage of adaptive optics to obtain a sharper, clearer, larger image of the tiny capillaries in the eye. These are shown in a video format, allowing better focus and observation of blood cells moving through the vessels.

After imaging the eye, highly magnified retinal images are pieced together with software to provide still images or videos.

"We had not expected to see such striking changes to the retinas at such early stages," said Ann Elsner, professor and associate dean in the IU School of Optometry, and lead researcher. "We set out to study the early signs in volunteer research subjects whose eyes were not thought to have very advanced disease. There was damage spread widely across the retina, including changes to blood vessels that were not thought to occur until the more advanced disease states."

The eyes of diabetes patients typically have significantly thicker blood vessel walls than those without the disease, as well as varying capillary widths. In the study, the researchers observed patients in early stages of diabetes and found that these walls in their eyes grew in length to create corkscrew-shaped, looped capillaries.

"It is shocking to see that there can be large areas of retina with insufficient blood circulation," Burns said. "The consequence for individual patients is that some have far more advanced damage to their retinas than others with the same duration of diabetes."

Such observations have not been made in the past because they are only visible at microscopic levels, the researchers said, noting that simply magnifying the image does not provide a close enough view of the retina to detect such symptoms early.

Further studies must be conducted to determine whether efforts such as improved control of blood sugar or a change in medication could stop or even reverse retinal damage, and how advanced a patient’s condition must be before those efforts are considered moot.

The research is published in Biomedical Optics Express (doi: 10.1364/BOE.5.000961).

For more information, visit: www.indiana.edu