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Updated on February 16, 2023
Diabetes is a condition that prevents your body from producing or responding to insulin, a hormone that helps bring sugar from the bloodstream and into cells, where it’s burned for energy. Over time, too much sugar—or glucose—in the blood can lead to heart problems, kidney problems, and nerve problems, especially in the hands and feet. Diabetes can also damage the blood vessels in the eyes, leading to vision troubles and, potentially, blindness.
Diabetic retinopathy is the leading cause of blindness for everyone from college students to retirees. “I see quite a few people with diabetes who have complications in their eyes,” says Lauren Zimski, MD, an ophthalmologist in Denver, Colorado. “As diabetes damages blood vessels, it affects blood flow to the retina, leading to loss of vision.”
Eye anatomy
Think of your eye as a camera. Light enters through the lens, where it imprints on a piece of film or a processor. In this analogy, the retina is the film. The retina “translates” the light it receives from outside the eye and sends the signals through the optical nerve and into the brain.
With diabetes, sometimes these retinal blood vessels swell and leak fluid, and abnormal vessels can grow on the surface of the retina. Both of these changes can result in loss of vision or even blindness.
Where to start
If you have diabetes, are you definitely going to go blind? No, says Dr. Zimski, but it’s important to be aware of potential eye problems.
“When you’re newly diagnosed, you’re usually sent in for an eye exam,” she says. “It’s unusual to see any eye changes initially, but the longer someone has diabetes and the more poorly it’s controlled, the more likely it is to develop retinopathy.”
People with diabetes should see an ophthalmologist or optometrist every year for a dilated eye exam, according to the American Diabetes Association. The dilated eye exam causes the pupil to expand, allowing providers to view the back of the eye and check for leaky or abnormal blood vessels on the retina.
It’s all about management
Controlled diabetes makes diabetic retinopathy less likely, according to Zimski.
“The biggest thing is just having low hemoglobin A1C,” she says, referring to the test that measures the average blood glucose level over the previous three months. The same diet you would eat to lower blood sugar—one with little sugar but plenty of fruits, veggies, and fiber—can make it less likely for diabetic retinopathy to progress if you can keep your A1C tightly controlled.
That’s good news for people with diabetes, because it means the way you should be eating to control your diabetes is the same way to eat to protect your eyes.
A 2021 longitudinal study published in Maturitas followed more than 22,000 adults with diabetes in Iran for nearly four years and found that adherence to a Mediterranean diet was associated with a lower incidence of complications from diabetes, including diabetic retinopathy. The Mediterranean diet consists of lots of plant-based foods such as fruits and vegetables and plenty of legumes (beans, nuts, and seeds), as well as whole grains, lean meats, fish, seafood, and healthy oils like olive oil. These items largely replace options like red meats, butter and cream, and excessive sweets.
Fish might be particularly helpful. Fatty fish like tuna and salmon are good sources of vitamin D, which some research has linked to diabetic retinopathy. A small 2019 study published in International Journal of Retina and Vitreous found that low serum vitamin D levels were associated with more severe cases of diabetic retinopathy.
By making these healthier food choices, you can help protect your eyes against complications from diabetes.
