Diabetes can build up cholesterol in retina, affect eyesight

Researchers found that diabetes, age-related health conditions and other metabolic disorders can lead to a buildup of cholesterol in the retina, which can crystallise and lead to the development of diabetic retinopathy.

Diabetic retinopathy is a serious sight-threatening complication of diabetes and can cause permanent vision loss and blindness.

The study led by a team from the Michigan State University in the US showed that crystalised deposits are very reflective and can be seen in images of the retina. This is important because noninvasive retina evaluations can be done by most optometrists, creating an opportunity for earlier diagnosis for more people, they wrote in the paper published in the journal Diabetologia. 

"Retinopathy is the leading cause of preventable blindness and one of the most feared complications of Type 1 and Type 2 diabetes," said Julia Busik, MSU professor emeritus of physiology. 

"Within 20 years of developing diabetes, every individual with either Type 1 or Type 2 diabetes will have some degree of retinopathy. Current treatment approaches are very invasive and are only directed at the very late stage of retinopathy."

In the study, the researchers discovered that these cholesterol crystals are like the crystals found in atherosclerotic plaque that can form in arteries and cause heart attacks.

George Abela, chief of the MSU Division of Cardiology, helped the team identify ways to scan retinas using modified tissue preparation for scanning electron microscopy. This also helps researchers analyse the composition of the crystals, which typically result when there is too much cholesterol in one place.

"We are actively pursuing what can be done to lower cholesterol in the retina," said Tim Dorweiler, a doctoral candidate in the Molecular, Cellular and Integrated Physiology Program at MSU and first author of the paper. 

"The retina is a very isolated organ, just like the brain, and both have a blood barrier that separates them from the rest of the body. This is what makes the retina hard to study and extremely complex."

There is also hope that new treatments to address crystals formed by cholesterol could be less invasive than current options for diabetic retinopathy. And there are questions about other areas of the body where these crystals could be treated to prevent other diseases.