A widely used diabetes and weight-loss drug is now under closer attention after researchers discovered it may be linked to a higher risk of a serious eye disease that can cause blindness in older adults.
Scientists from the University of Toronto found that older people with diabetes who used semaglutidev were more than twice as likely to develop a dangerous eye condition called neovascular age-related macular degeneration, also known as nAMD.
The findings were published in the medical journal JAMA Ophthalmology and are raising new questions about the long-term safety of these increasingly popular medications.
Semaglutide belongs to a group of medicines called GLP-1 receptor agonists. These drugs have become extremely popular in recent years because they can help people lower blood sugar, lose weight, and reduce the risk of some heart problems.
Millions of people around the world now use them for diabetes treatment or weight management. Celebrities and social media discussions have also helped make these drugs widely known to the public.
Although the medicines have helped many people, doctors have continued studying possible side effects. Until now, most attention has focused on stomach problems, nausea, and digestive issues.
Researchers are now beginning to look more carefully at how these drugs might affect the eyes, especially in older adults who may already have a higher risk of vision problems.
The eye condition highlighted in the new study is called neovascular age-related macular degeneration. This is a severe form of age-related macular degeneration, often shortened to AMD. AMD is one of the leading causes of blindness and vision loss among older adults in Western countries.
There are two main forms of AMD. The dry form is more common and usually develops slowly over time. The wet form, also called neovascular AMD, is less common but much more dangerous. It can damage vision very quickly and may lead to permanent sight loss if not treated early.
The disease happens when abnormal blood vessels grow underneath the retina, the light-sensitive tissue at the back of the eye. These fragile blood vessels can leak blood and fluid into the eye, damaging the macula. The macula is the central part of the retina that allows people to read, drive, recognize faces, and see details clearly.
When the macula becomes damaged, people may notice blurry vision, dark spots in the center of their sight, or straight lines appearing wavy. In severe cases, people can lose much of their central vision, making everyday tasks difficult.
Researchers have been uncertain for years about whether semaglutide affects eye health. Earlier clinical trials had already raised some concerns.
Two major studies, known as SUSTAIN 6 and PIONEER 6, reported higher rates of diabetic eye problems in people taking semaglutide compared with those not taking the drug. There have also been rare reports of damage to the optic nerve, which carries visual information from the eye to the brain.
At the same time, some smaller laboratory studies suggested the medicine might actually help protect eye tissue. Because the evidence pointed in different directions, scientists wanted to study the issue more carefully in a large real-world population.
To do this, the Canadian researchers examined health records from 139,002 adults in Ontario between 2020 and 2023. All of the participants were aged 66 or older and had diabetes.
Among them, 46,334 people had used semaglutide or related GLP-1 medications for at least six months. The remaining participants had never used these drugs.
The scientists used advanced statistical methods to compare the two groups while accounting for many other health differences that could affect the results.
After analyzing the data, they found that people taking GLP-1 drugs had more than double the risk of developing neovascular AMD compared with people not using the medications.
The study also showed that longer use of the drugs appeared to increase the risk even more. People who had taken the medications for more than 30 months were more than three times as likely to develop the eye disease.
Researchers also found that older age and a history of stroke or blood vessel problems in the brain were linked to a higher chance of developing the condition.
Even though the results are concerning, scientists say it is still too early to prove that semaglutide directly causes the eye disease. Diabetes itself can already damage blood vessels and increase the risk of many eye problems. Researchers say other unknown factors may also play a role.
Because of this, more studies will be needed before doctors can fully understand the connection. Future research may help explain whether the drug itself affects blood vessels in the eye or whether the risk is related to rapid changes in blood sugar, long-term diabetes damage, or other medical conditions.
For now, researchers recommend that doctors closely monitor the vision and eye health of patients taking semaglutide, especially older adults and those who have been using the drug for a long time. Regular eye exams may help detect early signs of damage before vision loss becomes permanent.
The study highlights the importance of continuing to track the long-term effects of popular medications even after they become widely used. Semaglutide has already changed the treatment of diabetes and obesity for millions of people, but scientists say it is important to balance the benefits of these drugs with careful monitoring of possible risks.
As more people begin taking these medications for weight loss and diabetes, understanding their long-term effects on vision may become increasingly important. Researchers hope future studies will provide clearer answers and help doctors better protect patients from serious eye complications.
If you care about wellness, please read studies about nutrients that could combat inflammation in older people, and essential foods for healthy aging.
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