A new study from the University of Toronto has raised serious concerns about a popular drug used to treat diabetes and help with weight loss.
The drug is called semaglutide and is sold under brand names like Ozempic and Wegovy.
Researchers found that older adults with diabetes who used semaglutide had more than twice the risk of developing a serious eye condition called neovascular age-related macular degeneration, or nAMD.
nAMD is a dangerous form of age-related macular degeneration, which is the top cause of vision loss in older adults in Western countries. Unlike the more common dry form, nAMD can lead to sudden and permanent loss of central vision.
This happens because abnormal blood vessels grow in the retina and leak fluid or blood, which damages the macula—the part of the eye responsible for sharp central vision.
Semaglutide belongs to a group of drugs called GLP-1 receptor agonists. These drugs are widely used to lower blood sugar in people with type 2 diabetes and can even reduce the risk of heart disease. In recent years, semaglutide has also gained fame as a weight-loss drug, with strong media promotion and widespread use.
But the drug’s effects on eye health were not the focus when it was first developed. Some early warning signs appeared in past clinical trials, like SUSTAIN 6 and PIONEER 6, where people taking semaglutide had more diabetic eye problems.
There have also been reports of damage to the optic nerve. On the other hand, some small lab studies suggested that semaglutide might protect the eye, so experts weren’t sure what to believe—until now.
In this new study, which was published in JAMA Ophthalmology, scientists looked at health records from 139,002 people aged 66 and older in Ontario from 2020 to 2023. All of them had diabetes. Of these, 46,334 had been using semaglutide or other GLP-1 drugs for at least six months. The remaining 92,668 people had never taken the drug.
The researchers used advanced analysis tools to compare the two groups. They found that people using semaglutide had a much higher risk of being diagnosed with nAMD.
In fact, the risk was more than double—an adjusted hazard ratio of 2.21. The risk grew even more the longer the drug was used. For those on semaglutide for over 30 months, the risk was more than three times higher, with a hazard ratio of 3.62.
The study also found that older age and a history of strokes or other brain-related blood vessel problems increased the risk even more.
These results raise new concerns about long-term side effects of semaglutide. Although it helps with diabetes and weight loss, the potential link to vision loss could change how doctors use the drug.
Experts say more research is needed to find out why this risk exists. Is the drug directly harming the eye, or is the effect related to diabetes itself or some other unknown cause?
For now, the researchers suggest that doctors monitor the eye health of patients taking semaglutide, especially those using it for a long time. Regular eye exams could help catch problems early before vision is permanently damaged.
As more people begin using semaglutide, especially older adults who are already at risk for eye disease, this study shows the importance of understanding long-term effects. It’s a reminder that even helpful medications can come with hidden risks.
The research findings can be found in the journal JAMA Ophthalmology.
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