Semaglutide, the active ingredient in Ozempic and Wegovy, has become an extremely popular medication thanks to its effectiveness in weight loss. But a growing body of research has linked the drug to some serious side effectsIncluding pancreatitisinflammation of the pancreas and gastroparesis, a paralysis of the stomach. Now there’s a new concern to add to the list: it may increase your risk of developing a blinding eye disease.
That’s the main conclusion of a new study published in JAMA Ophthalmology. For the study, researchers analyzed medical records of more than 17,000 patients in Mass eye and ear which have been treated for six years since the launch of Ozempic. Patients were divided into those diagnosed with diabetes and those who were overweight or obese. Patients taking semaglutide for these conditions were compared with those taking other medications for diabetes or weight loss.
The researchers then looked at the rate of patients diagnosed with NAIÃO, a rare condition that is the second leading cause of optic nerve blindness. NAION is believed to be caused by reduced blood flow to the optic nerve head. It can lead to permanent visual loss in one eye, which may develop painlessly and suddenly or over several days before stabilizing. There are currently no effective treatments for NAION.
After analyzing the data, researchers found that people with diabetes who used semaglutide were four times more likely to be diagnosed with NAION. Rates for people who were overweight or obese were seven times more likely to be diagnosed with NAION.
It’s certainly understandable that those taking semaglutide would be concerned. So Yahoo Life asked an ophthalmologist to explain just how concerning the risk is, along with what you can do to stay on top of your eye health if you use semaglutide.
How worrying is that?
It is important to make some reservations. One is that Mass Eye and Ear is a specialized ophthalmology institute that serves a large number of people with rare eye diseases, so the population may have been skewed a bit. Another is that the researchers were unable to tell whether patients actually took the medication or whether they filled their prescription and stopped taking it at some point (which may or may not have affected their risk).
That said, there appears to be a connection here – it’s just not clear why. “We didn’t do the study because we had any expectation that the medicine would cause this disease,” Dr. José Rizzo, the study’s principal investigator and director of the neuro-ophthalmology service at Mass Eye and Ear, told Yahoo Life. “We did this because we saw several cases of NAION in close succession. This seemed unusual to us.”
Semaglutide has “multiple mechanisms of action,” says Rizzo, and adds that there are “some clues as to why it might cause NAION, but we don’t know at the moment.” NAION is caused by a stroke in the optic nerve, which makes it difficult to prevent. “For the most part, it just happens, and when it happens, that’s it,” he says.
However, doctors are not yet worried. “Any medication you take has an increased risk of side effects,” Bavand Youssefzadeh, an ophthalmologist in Beverly Hills, California, tells Yahoo Life. “Patients taking these medications already have diabetes or are overweight, so they are already at increased risk for eye disease.”
Youssefzadeh stresses that NAOIN is “still very rare,” although it is common for people to notice changes in vision when they lose weight or stabilize their blood sugar with semaglutide. “If you change your weight or have high or low blood sugar, the lens in your eye will change shape,” says Youssefzadeh.
Rizzo points out that his study didn’t show cause and effect – it just found a link. “We hope this will lead to a much larger study to examine whether there is cause and effect,” he says.
He believes that “extra information in medicine is useful, and the more you understand about something, the better off you are.” The study’s findings are “information we didn’t previously have.” As a result, Rizzo says it “should at least be taken into consideration as a risk-benefit analysis by a patient.”
Semaglutide may also be helpful for some people with vision problems
Complicating matters, semaglutide may also help people with diabetes-related eye conditions. Research presented in American Academy of Ophthalmology Annual Meeting in 2023 found that most adults aged 51 to 75 with diabetes who took semaglutide did not develop diabetic retinopathy – an eye disease that can cause vision loss and blindness in people with diabetes. Those who already had diabetic retinopathy did not get worse with the use of semaglutide.
That said, the AAO warned in 2021, that semaglutide was associated with early worsening of diabetic retinopathy. But having uncontrolled diabetes – regardless of medication – is also linked eye diseases, including diabetic retinopathy and glaucomaa disease that damages the optic nerve.
“Sometimes patients taking semaglutide find that their diabetic retinopathy has increased a little, but overall, these medications should help you with diabetic retinopathy because your blood sugar will decrease and may help you lose weight,” says Youssefzadeh .
Semaglutide “will help most people with diabetic retinopathy,” says Youssefzadeh, adding, “I’ve personally seen patients do much better on this medication.”
How to protect your eye health with semaglutide
If you’re taking semaglutide or interested in using the medication, doctors say there are some things you can do to stay on top of your eye health.
Because your vision may change when you lose weight or change your blood sugar control, Youssefzadeh recommends that you see an ophthalmologist when starting semaglutide. “If you start to notice changes, especially in the first four to eight months, just see your eye doctor and say, ‘This is what’s happening,’” he says.
Semaglutide can increase your risk of dry eye and cause vision changes, so your doctor may recommend that you start artificial tears or change your glasses prescription if you use them, he says.
It is also important to note that along with diabetes, other health conditions increase the risk of NAOIN, including high blood pressure, high cholesterol, and obstructive sleep apnea. So keeping these conditions under control can help.
But Youssefzadeh emphasizes that people should not panic about the risk of developing NAOIN when taking semaglutide. “This is not a common thing we see in the clinic,” he says.
Rizzo agrees. “I don’t want people to be alarmed by this,” he says.
