A widely used medicine for diabetes and weight loss is now raising new concerns among scientists. The drug, called semaglutide, has become very popular in recent years.
It is commonly sold under brand names such as Ozempic and Wegovy. Many doctors prescribe it to help people with type 2 diabetes control their blood sugar levels. It has also become well known for helping people lose weight.
However, a new study suggests the drug may have an unexpected risk for eye health, especially among older adults. Researchers from the University of Toronto have found that people with diabetes who use semaglutide may have a much higher chance of developing a serious eye disease.
The condition is called neovascular age‑related macular degeneration, often shortened to nAMD. This disease is a severe form of age‑related macular degeneration. It is already one of the leading causes of vision loss among older adults in Western countries.
While the more common “dry” form of macular degeneration usually progresses slowly, the neovascular form can damage vision very quickly.
The disease occurs when abnormal blood vessels begin to grow inside the retina. The retina is the thin layer of tissue at the back of the eye that senses light and sends visual signals to the brain. These abnormal blood vessels can leak blood or fluid into the eye.
When this happens, the macula becomes damaged. The macula is the central part of the retina that allows people to see fine details, read, and recognize faces. Damage to this area can lead to sudden and permanent loss of central vision.
Semaglutide belongs to a group of medicines called GLP‑1 receptor agonists. These drugs work by helping the body control blood sugar levels and by reducing appetite.
Because of these effects, they have become very useful for treating people with type 2 diabetes and for helping some patients lose weight. Doctors also value these drugs because they can reduce the risk of heart disease in certain patients.
Despite these benefits, questions about possible eye side effects have existed for several years. Earlier clinical trials of semaglutide, including large studies known as SUSTAIN‑6 and PIONEER‑6, reported that some patients taking the drug developed more eye complications related to diabetes.
There have also been reports suggesting possible damage to the optic nerve. At the same time, some small laboratory studies suggested the drug might actually protect certain eye cells. Because the results were mixed, scientists were unsure whether semaglutide truly increased eye risks.
To explore the issue more clearly, researchers carried out a large study using medical records from Ontario, Canada. The study included 139,002 adults aged 66 and older who had diabetes. The researchers looked at records from 2020 to 2023 to examine whether people taking semaglutide or similar drugs developed the eye disease.
Among these participants, 46,334 people had been taking semaglutide or other GLP‑1 drugs for at least six months. The remaining 92,668 individuals had never taken the drug. By comparing the health outcomes of the two groups, the researchers hoped to see whether the medication was linked to changes in eye disease risk.
After analyzing the data, the scientists found a clear pattern. Older adults who used semaglutide had a much higher risk of being diagnosed with neovascular age‑related macular degeneration.
The risk was more than twice as high compared with people who had never taken the medication. In statistical terms, the researchers reported an adjusted hazard ratio of 2.21.
The risk appeared to increase the longer people used the drug. For patients who had taken semaglutide for more than 30 months, the risk of developing the eye disease was more than three times higher. In this group, the hazard ratio reached 3.62.
The researchers also found that some people faced even higher risks. Older patients and those who had previously experienced strokes or other brain‑related blood vessel problems appeared to be especially vulnerable.
These findings do not necessarily mean that semaglutide directly causes the eye disease. The researchers note that more studies are needed to understand why this association exists. It is possible that the drug affects blood vessels in the eye, but it is also possible that the relationship is connected to diabetes itself or to other health factors.
Even so, the results highlight the importance of careful monitoring. Doctors may need to watch the eye health of patients who take semaglutide, particularly older adults and those who use the drug for a long period of time. Regular eye examinations may help detect early signs of damage before vision loss becomes permanent.
As semaglutide continues to grow in popularity for both diabetes treatment and weight management, understanding its long‑term effects is becoming increasingly important. This study serves as a reminder that even medications that offer major health benefits can sometimes carry unexpected risks.
The research was conducted by scientists from the University of Toronto and published in the journal JAMA Ophthalmology.
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