Diabetic patients taking GLP-1s may face increased risk of eye disease, study suggests

Fox News

6 days ago

Diabetes is the leading cause of vision loss in people between 18 and 64 years old, according to the American Diabetes Association — and the best way to prevent this is to control blood sugar levels.
Glucagon-like peptide-1 receptor agonists (GLP-1s), such as Ozempic and Mounjaro, have become popular medications for controlling diabetes and treating obesity — but new Canadian research suggests they can also lead to a paradoxical side effect in the form of eye problems.
A retrospective study conducted from January 2020 to November 2023 included more than 139,000 diabetic patients, some of whom were taking GLP-1s for at least six months and some who were not taking the medications over a three-year period.
The average age of the participants was 66 years old, and approximately 47% were women.
Researchers found that the participants taking the weight-loss medications had twice the risk of developing neovascular age-related macular degeneration (nAMD) compared to the people not taking them.
"There have been growing reports of [eye] adverse events with GLP-1 receptor agonists, but no clear consensus regarding their impact on age-related macular degeneration (AMD) progression," study author Dr. Rajeev Muni, an ophthalmologist and vice-chair of clinical research in the Department of Ophthalmology and Vision Sciences at the University of Toronto, told Fox News Digital.
"In particular, we observed a dose-response relationship — the longer patients were exposed to these medications, the greater their risk appeared to be," added author Reut Shor, a researcher in the department of ophthalmology and vision sciences at the University of Toronto.
The findings were published in the journal JAMA Ophthalmology.
Age-related macular degeneration (AMD) is the most common cause of vision loss in those aged 50 and older in the developing world, according to the American Society of Retinal Specialists.
Approximately 20 million adults in the U.S. have the condition.
It mainly affects people's central vision, which means they have a challenging time seeing in front of them, but their peripheral vision is intact, according to the National Institutes of Health (NIH).
There are two types of AMD – dry and wet.
Dry AMD, the most common type, occurs when small yellow deposits of protein develop under the macula, but symptoms may not occur in the early stages, experts said.
"The longer patients were exposed to these medications, the greater their risk appeared to be."
In about two out of every 10 cases, dry AMD develops into wet AMD — also known as neovascular age-related macular degeneration (nAMD).
With this more advanced type of disease, abnormal blood vessels form under the retina and start to leak, causing damage to the central part of the retina, known as the macula, according to WebMD.
"When this occurs, symptoms include loss of central vision, distortions in vision and blank areas missing in the central vision," Nishika Reddy, M.D., assistant professor of ophthalmology at Moran Eye Center's Midvalley Health Center at the University of Utah, told Fox News Digital. (She was not part of the study.)
Risk factors for nAMD include chronic heart failure, chronic kidney disease and diabetes – all of which often overlap with those who take GLP-1s, experts confirmed.
The study authors cautioned that their findings should be taken in the context of the overall higher risk of eye disease in older people.
The incidence of nAMD in the general population is about one in 1,000, and it doubled to two in 1,000 for the group taking the GLP-1s in the study.
However, the overall absolute risk is still small, according to the researchers.
The study's main limitation is that it was observational in nature, meaning the researchers could not confirm that GLP-1s medications cause neovascular age-related macular degeneration.
The study also could not draw conclusions about younger populations, the researchers acknowledged.
"Also, our findings apply only to diabetic patients aged 66 years or older, and cannot be directly generalized to non-diabetic individuals using GLP-1 receptor agonists for weight loss," Shor told Fox News Digital.
"While the risk of developing macular degeneration while on a GLP-1 drug is low, patients should be aware of the possible eye side effects."
GLP-1 receptors are present in the retina regardless of age or diabetes status — so theoretically, the risk could apply to younger populations.
More research is needed to better understand why diabetic people on GLP-1s have increased eye disease, Shor said.
"While the risk of developing macular degeneration while on a GLP-1 drug is low, patients should be aware of the possible eye side effects related to these types of medications," Reddy said.
If someone notices blurred or distorted vision, straight lines appearing wavy, or any new blind spots, they should seek medical attention, according to Muni.
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Early detection of eye disease is crucial, experts agree, as timely treatment can reduce the risk of vision loss.
The study authors said they hope their findings will empower patients to monitor for early symptoms.