Diabetes affects more than 1 in 10 adults worldwide and has been accompanied by an increase in vision-threatening diabetic retinal disease (DRD).

Concerningly, DRD is the leading cause of preventable blindness for those aged 20-74 years.

Multiple studies have shown that DRD screening remains challenging because patients often do not have any symptoms in the early stages and, therefore, misunderstand the importance of regular screenings.

In a recent publication in Diabetes Technology & Therapeutics, Thomas Gardner, M.D., M.S., professor of ophthalmology and visual sciences and a member of Caswell Diabetes Institute, discusses current screening recommendations and treatment options for DRD.

Diabetes can damage multiple parts of the body, including kidneys, nerves and eyes. DRD affects the blood vessels and nerve cells in the retina, resulting in hemorrhages, abnormal blood vessel growth and loss of critical nerve cells.

“People usually are not motivated to take action until their vision is threatened, by which time they might develop late-stage DRD,” Gardner said.

The American Diabetes Association therefore recommends that adults with type 2 diabetes have their first eye exam when they are diagnosed and those with type 1 diabetes have their first eye exam within five years of diagnosis.

“The guidelines for type 1 and type 2 diabetes are different because adults who have the latter can develop vision complications before they become aware of their condition,” Gardner said. 

“Importantly, adolescents and young adults are at a higher risk, largely because it is very difficult for them to control their diabetes.”

Diabetes requires constant monitoring of blood sugar and diet.

“Sometimes patients can take the same amount of medication, eat the same food and get the same amount of exercise only to find that their blood sugar levels fluctuate. This makes it hard to manage,” Gardner said.

The biggest challenge for patients is lowering their blood sugar levels without becoming hypoglycemic, which is characterized by shakiness, uneven heartbeat, sweating and dizziness.

Although improvements in insulin pumps and continuous glucose monitors have made it easier to control blood sugar levels, Gardner emphasizes treating the other aspects of diabetes.

“People with diabetes need to have regular health checkups to ensure that their blood pressure is normal and all their organs are functioning correctly. Establishing good control on every facet of diabetes is essential,” he said.

Although the effect of diabetes on the retina is not completely understood, researchers have found several drugs that are promising.

In particular, those that help control blood pressure and lipid levels, including SGLT inhibitors, GLP-1 receptor activators and fenofibrate, can help slow the progression of DRD. However, these are generally prescribed by physicians and not ophthalmologists. 

“Although these drugs were developed to treat other disorders, including kidney disease, heart disease and high cholesterol, ongoing studies have shown they can reduce the risk of vision loss in patients with diabetes,” Gardner said.

As a part of Caswell Diabetes Institute's Mary Tyler Moore Vision Initiative, Gardner and his colleagues are hoping to develop screening techniques that can catch DRD in its early stages and therapies that preserve and restore vision in people with diabetes.

“The prognosis for vision in people with diabetes is better now than it's ever been in the past. There's every reason to be optimistic that vision loss can be avoided with regular screenings and treatment,” Gardner said.

Additional authors: Ryan F. Bloomquist, Ph.D., M.P.H., University of South Carolina and Doan Tam Bloomquist, M.D., Charlie Norwood Veterans Affairs Hospital.

Paper cited: “Current Treatment Options for Diabetic Retinal Disease,” Diabetes Technology & Therapeutics. DOI: 10.1089/dia.2024.0548

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