University study aims to detect early signs of vision loss due to diabetes

A $3.3 million study at the University of Houston College of Optometry will track the health of patients with prediabetes and diabetes to identify those who might develop eye problems and be at risk for future vision loss. The study is led by Wendy Harrison, associate professor, and funded by the National Eye Institute.

Vision loss in type 2 diabetes results from diabetic retinopathy, caused by damage to blood vessels in the retina. The disease can appear without warning.

“The ability to predict which patients are most at risk could constitute a significant advance in diagnosis and management of diabetes, which has reached epidemic proportions,” said Harrison. “Early diagnosis and detection, especially if location-specific, could aid in delaying diabetic retinopathy and over the long term, saving sight.”

Diabetes is the leading cause of vision loss among working-age Americans. Approximately 44% of American adults have prediabetes, but it is not currently known when and how prediabetes affects the eye. Many patients with prediabetes are unaware of their condition.

Although patients with prediabetes are known to have impaired fasting glucose, impaired glucose tolerance, and elevated hemoglobin A1c levels, there remains a significant gap in understanding how and when prediabetes impacts eye health.

“It is important that we close this gap as there are no treatments in the eye outside of glycemic control for early type 2 diabetes or prediabetes, and to learn which type of glucose processing changes are most related to eye disease,” said Harrison.

Harrison’s team is conducting unique research by studying both the front and back of the eye along with different types of glucose dysfunctions. The team includes Rachel Redfern, Maria Walker, Kaitlyn Sapoznik from Optometry; Marc Hamilton from Health and Human Performance; Ted Zderic; Julia Benoit; Deborah Hamilton; and Bismark Owusu-Afriyie.

To explore how glucose dysregulation affects various parts of the eye such as the vascular retina, neural retina, cornea, and tear film, they will investigate whether tests like fat distribution analysis, activity levels monitoring, and oral glucose tolerance testing in type 2 diabetes patients can predict ocular health outcomes.

“Our central hypothesis is that local retinal oxygenation is altered by changes in glucose tolerance. This drives the relationship between vessel changes and retinal function in local retinal areas,” said Harrison.

The researchers will compare subjects initially then follow up after one year and two years to assess ocular and metabolic changes over time.

“We expect that differences in impaired glucose tolerance phenotypes will alter ocular testing over time," said Harrison.