A new study found that older adults with diabetes who were taking GLP-1s—a class of medications that have become popular for weight loss—had a higher risk of developing neovascular age-related macular degeneration (nAMD), an eye condition that can lead to blindness.
“Notably, this risk appeared to increase with longer duration of exposure, representing a dose-response effect,” co-author Reut Shor, MD, of the Department of Ophthalmology and Vision Sciences at the University of Toronto, Canada, told Health. “This suggests that while GLP-1s offer many systemic benefits, their potential ocular risks, particularly for advanced age-related macular degeneration, need to be better understood and carefully monitored.”
Here’s what to know about neovascular age-related macular degeneration, what the study found exactly, and whether experts think people taking GLP-1s should be worried.
Neovascular age-related macular degeneration, also called wet AMD, is the rarer but more advanced form of age-related macular degeneration, a disease of the retina that specifically affects the back of the eye. This “wet” version of AMD (there’s a dry type, too) occurs when abnormal blood vessels develop, impairing vision. Symptoms, such as fading colors and visual distortions, tend to come on suddenly and progress quickly.
Wet AMD can lead to permanent blindness, but there are effective treatments that can prevent this from happening.
Nearly 1.5 million Americans have an advanced form of AMD, and wet AMD makes up about 10% to 15% of AMD cases.
Several studies have revealed a connection between GLP-1s and eye-related issues, such as the progression of diabetic retinopathy, a complication of diabetes, and nonarteritic anterior ischemic optic neuropathy (NAION). However, there’s been “no real consensus on whether it affected the progression of AMD,” said Shor, referring to GLP-1 use. “This made me very curious to explore what we would actually find when looking at real-world, population-based data.”
For their investigation, Shor and her colleagues conducted a large, population-based study in Ontario, Canada, that captured comprehensive health data on over one million people diagnosed with diabetes between 2020 and 2023. Among them, about 73,000 people had used GLP-1s for at least 6 months, while about 996,000 had never used these medications. Nearly 98% of people taking a GLP-1 took semaglutide, the active ingredient in Ozempic and Wegovy.
Researchers paired patients with similar characteristics, such as age, gender, and health conditions, so any differences they observed were more likely due to exposure to GLP-1s than other factors.
“In short, we started with a large pool of over 1 million and created carefully matched groups to allow for a fair and rigorous comparison,” Shor said.
People who took a GLP-1 were, on average, more than twice as likely to develop wet AMD. The association grew stronger the longer the medication was used.
“GLP-1s have become preferred treatments in complications-centric diabetes care, but this study reminds us to monitor eye health in patients on these medications, especially with long-term use,” Isaacs said.
While the study identifies an association between GLP-1 use and wet AMD in people with diabetes, it doesn’t prove that the medications cause the condition, pointed out Scott Isaacs, MD, president of the American Association of Clinical Endocrinology.
“Confounding factors could have affected the outcome, including smoking status, UV exposure, and dietary patterns—known AMD risk factors that were not adjusted for due to gaps in data,” Isaacs told Health. It’s possible that these unmeasured factors—or even diabetes itself—might drive the link.
Furthermore, patients on GLP-1s are likely to receive more frequent medical care, and this could have potentially increased nAMD detection rates compared to the control group, Isaacs added. And, Shor noted, relying on an administrative database doesn’t always give an accurate portrayal of a person’s condition.
That said, it’s possible that “rapid glycemic improvement with GLP-1s” or any other medications may worsen diabetic retinopathy in people who already have it, Isaacs noted.
Sunir Garg, MD, a spokesperson for the American Academy of Ophthalmology and professor of ophthalmology at Wills Eye Hospital, told Health that more research is needed to determine if the study results are replicated in other population groups over a longer period of time, especially given that other common diabetes medicines—such as SGLT-2 inhibitors or metformin—have been associated with a lower risk of developing nAMD.
“We don’t know if this particular class of medications affects the eye differently than other classes of medications used to treat diabetes or if this particular study found a different conclusion for reasons we don’t fully understand,” he said.
The research should encourage awareness—not raise alarm, Shor said.
Per Isaacs, the AACE isn’t changing any recommendations based on the findings. But the study is even more reason for established protocols, such as screening high-risk patients and considering alternative medications when appropriate, to be followed, he said.
“For most patients, cardiometabolic benefits outweigh the low risk of wet nAMD,” Isaacs said. “However, in older adults with preexisting retinal conditions and prolonged GLP-1 use, risk-benefit discussions are important.”
For those concerned about nAMD, Garg recommends a simple test you can do at home: covering each eye separately once or twice a week while looking at objects with fine details, such as a newspaper or wall clock.
“Looking at objects with straight lines such as door jams, window blinds, or tiles can also make detecting distortion easier,” he said. “Should central blurriness or distortion occur, patients should see their ophthalmologist.”
