Individualized exam schedule for diabetic eye disease

For the study, people with diabetes had eye exams that included photos of the retina. Bkilzer/iStock/Thinkstock

People with diabetes have blood sugar (glucose) levels that are too high. Over time, high levels of blood glucose can cause health problems, such as eye damage. The part of the eye most at risk for damage is the retina, the light-sensitive tissue that lines the back of the eye. Without treatment, retinal damage can lead to permanent blindness.

Signs of diabetic retinal disease (retinopathy) can be detected through a comprehensive dilated eye exam before symptoms occur and in time take action to prevent vision loss. Pupil dilation, or widening, is an important part of the exam because it allows a much better view of the retina. To diagnose diabetic eye disease while it is treatable, experts currently suggest that people with type 1 diabetes get an eye exam at least once a year starting three to five years after diagnosis.

To find out whether the exam frequency could be tailored to individual risk, researchers analyzed 30 years of data from about 1,400 people with type 1 (insulin-dependent) diabetes. The study was funded mainly by NIH’s National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). NIH’s National Eye Institute (NEI) and others also provided support. Results were published on April 20, 2017, in the New England Journal of Medicine.

The researchers analyzed data from about 24,000 eye exams with retinal photography. The results enabled them to develop a model to predict the likelihood of an individual progressing to significant, vision-threatening retinopathy based on their current retina exam and blood glucose level.

The analysis showed that, among people with type 1 diabetes and recent blood glucose level near the normal range (as measured by an A1C level of 6%), those with no detectable retinal damage could be screened every four years. Those with mild retinal damage could be examined every three years without increasing the risk of vision loss. People with moderate or severe retinal damage, the researchers found, should be examined more often than the current recommendation: every six or three months, respectively. On average, this tailored schedule would result in fewer eye exams and earlier detection and treatment to save vision.  

People who have type 1 diabetes and poorer blood glucose control (such as a current A1C of 8 to 10%) are at risk of developing retinal disease sooner. For that reason, the researchers recommended more frequent eye exams for these people.

“The results could save money and time while getting better health outcomes—a win all around,” says Dr. Catherine Cowie, who oversaw the study at NIDDK. “The findings from this landmark type 1 diabetes study will inform a precision medicine approach, where treatment is tailored to the individual.”

The new evidence-based exam schedule could prove more efficient than the annual schedule at detecting vision-threatening retinal disease. The next step is for experts to consider these findings for modifying clinical guidelines for people with type 1 diabetes.