How to prevent, spot and treat the most common type of eye disease if you have diabetes

This story first appeared in Healthy You - November 2024, The Gazette’s quarterly health publication.

Not everyone going to an eye doctor needs glasses.

“There are people who start coming to see us, not necessarily because they need glasses, but because their physicians have diagnosed them with diabetes,” said Dr. Brian Privett, an ophthalmologist with Iowa Eye Center in Cedar Rapids.

For people with diabetes, blindness can be a real threat. Because serious eye disease can be present with few symptoms or even none at all, people with diabetes should have a thorough eye exam at least once a year. The dilated eye exam widens the pupil, allowing the ophthalmologist a better look at the retina, the light-sensitive tissue at the back of the eye.

“It’s the one place in your body where you cans see blood vessels,” Privett said. “Your eye is the one place we can look directly at the blood vessel.”

Diabetic retinopathy (DR) is the most common type of serious eye problem associated with diabetes. The high glucose (blood sugar) levels that accompany Type 1 and Type 2 can damage the retina’s delicate blood vessels, causing a proliferation of vessels or a thickening of their walls.

“The damage to these blood vessels can produce few or no symptoms and can suddenly bleed into the eye,” said Dr. Kevin Peterson, vice president of primary care at the American Diabetes Association. “A bleed into the eye can lead to sudden and permanent vision loss.”

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Diabetes is the leading cause of vision loss and blindness in people 18-64 years old. About 9.6 million Americans have DR, about 28 percent of people with diabetes over 65 years of age. The number of individuals with diabetic retinopathy is predicted to increase by 48 percent by 2030, according to Peterson.

Macular edema, a complication of DR, is a slower leakage of fluid into the areas of the eye responsible for sharp vision, usually causing blurred vision. The annual exams can give advance warning of both conditions.

“Many times, if someone’s just been diagnosed, we won’t see that yet, but we need to get a baseline to track vision changes,” Privett said. “With mild retinopathy, we’re usually just doing a screening exam once a year, and we’re giving reports to their doctor.”

The patient’s general practitioner can then work with them to manage their glucose levels. Maintaining healthy levels can also prevent glaucoma and cataracts, both often diabetes-related conditions.

“Maintaining blood sugar control over time dramatically reduces the likelihood of developing DR,” Peterson said. “The likelihood of other eye problems is also reduced with good long-term blood sugar control.”

In between annual exams, people with diabetes should be aware of symptoms such as intermittent blurred vision, spots, or “floaters,” which look like dark wavy strings floating in the field of vision.

“I always tell people to look out for sudden gray spots in the center of your vision,” Privett said. “If there are new floaters, you can get bleeds in the eye. Those are the two components of DR that can cause sudden symptoms.”

Privett also occasionally sees patients with symptoms who haven’t yet been diagnosed with diabetes.

“From time to time, there are people with high blood sugar who haven’t been to their doctor,” he said. “We refer them over (to their doctor) when we do diagnose diabetes.”

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While eye damage from DR can’t be reversed, new treatments are becoming available that can slow its development.

“Now we have injections we can put in the eye that actually work quite well,” Privett said. “The better you take care of your eyes and your blood sugars and your screenings, the better we can manage those. There actually is a lot that can be done for someone that has DR. That’s one reason we screen.”

Besides managing blood sugar, people with diabetes can protect their vision through basic healthy lifestyle strategies: