A new study from the University of Toronto has raised concerns about a popular diabetes and weight-loss drug.
Researchers found that older adults with diabetes who used semaglutide—sold under brand names like Ozempic and Wegovy—had more than double the risk of developing a serious eye condition called neovascular age-related macular degeneration (nAMD).
nAMD is a less common but more dangerous form of age-related macular degeneration, which is the leading cause of vision loss in older adults in Western countries.
Unlike the dry form, neovascular AMD can cause sudden and irreversible loss of central vision.
This happens because abnormal blood vessels grow in the retina and leak fluid or blood, damaging the macula, the part of the eye responsible for sharp, central vision.
Semaglutide belongs to a class of drugs called GLP-1 receptor agonists. These drugs have transformed the treatment of type 2 diabetes by helping lower blood sugar levels and even reducing the risk of heart disease.
More recently, semaglutide has become a household name for its weight-loss benefits, thanks to heavy media promotion and rapid uptake. However, the possible effects on the eyes were not part of the original focus of drug development.
Some early warnings appeared during large clinical trials, such as SUSTAIN 6 and PIONEER 6, which showed increased rates of diabetic eye problems in people taking semaglutide. There have also been isolated reports of damage to the optic nerve.
On the flip side, some small lab studies have hinted that the drug might actually protect the eye. As a result, experts have remained uncertain—until now.
In this new population-based study, published in JAMA Ophthalmology, researchers analyzed the health records of 139,002 people aged 66 and older in Ontario between 2020 and 2023. All of them had diabetes. Among these, 46,334 had been prescribed semaglutide or other GLP-1 receptor agonists for at least six months. The remaining 92,668 had never used these drugs.
After comparing both groups using advanced statistical methods, the researchers found that those who used GLP-1 receptor agonists had a much higher risk of being diagnosed with neovascular AMD.
Specifically, they had more than twice the risk—an adjusted hazard ratio of 2.21—compared to those who hadn’t used the drugs. The risk grew even higher with longer use. People who had been taking the medication for over 30 months had a hazard ratio of 3.62, meaning their risk was more than three times higher.
Age and previous strokes or other brain-related blood vessel problems also increased the risk of nAMD.
This study adds to growing concern about the possible side effects of semaglutide on the eyes. While it has shown major benefits for managing blood sugar and reducing weight, this potential link to a serious vision-threatening condition could change how doctors monitor patients on long-term treatment.
Experts say more research is needed to understand why this risk exists. Is it the drug itself causing damage? Could it be related to the underlying diabetes? Or is there something else going on that hasn’t yet been identified?
For now, the researchers recommend that doctors keep an eye—literally—on patients taking semaglutide, especially those using it for long periods. Periodic eye exams could help detect early signs of retinal problems before permanent damage occurs.
As semaglutide use continues to grow, the findings highlight the importance of looking at the long-term effects of blockbuster drugs—especially when they are being used by millions of people, many of whom are older and already at higher risk for eye disease.
If you care about eye health, please read studies about how vitamin B may help fight vision loss, and MIND diet may reduce risk of vision loss disease.
For more information about eye disease, please see recent studies about how to protect your eyes from glaucoma, and results showing this eye surgery may reduce dementia risk.
The research findings can be found in JAMA Ophthalmology.
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