What Doctors Want You to Know About Weight Loss Drugs and Vision Loss
New research links a rare and blinding eye condition to semaglutide.
Semaglutide is the active ingredient in Ozempic and Wegovy.
Doctors recommend that people don't panic over the findings.
There’s been a lot of talk about potential side effects from using medications to lose weight, including taking Ozempic, a type 2 diabetes medication that’s used off-label for weight loss. Those range from having so-called “Ozempic face” to the potential of developing stomach paralysis. Now, there’s speculation that a new serious condition is linked to semaglutide (the main active ingredient in Ozempic and weight loss drug Wegovy): vision loss and blindness.
Research published in JAMA Ophthalmology found a connection (note: not correlation) between semaglutide and a rare but serious eye condition called non-arteritic anterior ischemic optic neuropathy (NAION).
Meet the experts: Joseph Rizzo, M.D., director of neuro-ophthalmology service at Mass Eye and Ear, Mir Ali, M.D., a bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CA, Howard Krauss, M.D., a surgical neuro-ophthalmologist and director of Pacific Neuroscience Institute’s Eye, Ear & Skull Base Center in Santa Monica, CA, Jonathon Ross, O.D., assistant clinical professor at The Ohio State University College of Optometry
For the study, researchers analyzed medical records of more than 17,000 patients who were treated at a prominent specialty eye clinic from December 1, 2017, through November 30, 2023. The researchers divided patients into those who had diabetes and those who had overweight or obesity. They also compared people who took semaglutide for those conditions to patients who took other medications for diabetes or weight loss, and looked at the rate at which patients were diagnosed with NAION.
While overall cases of NAION were low, the researchers found that people who had diabetes and used semaglutide were more than four times more likely to be diagnosed with NAION than those who didn’t take the medication. Those who had overweight or obesity were seven times more likely to be diagnosed with the devastating eye condition.
Before you panic, know this: NAION is incredibly rare, even in people who take semaglutide. Still, it’s understandable to have questions. Here’s what we know.
What is NAION, exactly?
NAION is a rare condition and the second-leading cause of optic nerve blindness, according to Brigham and Women’s Hospital. It’s thought to be caused by reduced blood flow to the optic nerve head, and the condition is more common in people who have conditions like diabetes, high blood pressure, and sleep apnea, the organization says.
NAION is serious: It can lead to permanent vision loss, and usually develops without pain. It also can come on suddenly or over several days before it stabilizes. Unfortunately, there are no effective treatments for NAION, per the American Academy of Ophthalmology (AAO).
Does Ozempic cause vision loss?
It’s important to note a few things here. One is that the study merely found a link between patients who used semaglutide and NAION—it didn’t prove that semaglutide use caused NAION. “Our study does not show cause and effect,” says study co-author Joseph Rizzo, M.D., director of neuro-ophthalmology service at Mass Eye and Ear.
It's also crucial to stress that Mass Eye and Ear, which is where the patients were treated, is a specialized eye institute that sees a lot of people with rare eye conditions. As a result, the population that was studied may have been a little skewed.
Finally, the researchers didn’t know if the patients actually took semaglutide or if they continued taking it—they just knew that they had a prescription for the medication.
Dr. Rizzo says that he and the fellow researchers decided to study this after seeing several cases of NAION in patients who took semaglutide, but they still don’t know why there may be a link. “It wasn’t like we knew about the mechanisms of semagluide and said, ‘Hey, this could cause a stroke of the optic nerve,’” he says.
There are "many compounding factors that make it difficult to come to a conclusion," says Howard Krauss, M.D., a surgical neuro-ophthalmologist and director of Pacific Neuroscience Institute’s Eye, Ear & Skull Base Center in Santa Monica, CA. He recommends that future research look into whether patients with more severe type 2 diabetes or obesity were more likely to be prescribed semaglutide, and whether they had obstructive sleep apnea. "We've known for several years now that obstructive sleep apnea is a factor in NAION," he says. "Weight loss sometimes reduces the significance of that," which could be why some people with obstructive sleep apnea were prescribed semaglutide, he adds.
What do Ozempic and semaglutide drugs do to your brain?
Semaglutide works in a few ways in the body, including messaging in the brain. Semaglutide mimics a protein in your body called glucagon-like peptide 1 (GLP-1), explains Mir Ali, M.D., a bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CA.
When you take semaglutide, it activates GLP-1 receptors in your body, which causes your body to produce more insulin, a hormone that helps escort glucose into your body’s cells to be used for energy.
“At the same time, semaglutide signals to your brain to eat less and store fewer calories,” Dr. Ali says. While all of this is happening, the medication also tells your gut to move food through more slowly. With all of this going on at once, people on semaglutide will usually feel less hungry, he says.
Type 2 diabetes and vision loss
To further complicate things, there is a link between vision loss and type 2 diabetes. Again, one of the risk factors for developing NAION is having diabetes, which puts people with the condition at an increased risk of developing the eye condition at baseline. Given that semaglutide is also used to treat type 2 diabetes, it can be tricky to parse all this out.
There’s also a condition called diabetic retinopathy that can develop in people with diabetes. Diabetic retinopathy affects blood vessels in the retina, which is the light-sensitive layer of tissue in the back of your eye, and can lead to blindness, per the National Eye Institute (NEI).
"Chronically elevated blood sugar levels can cause damage to the inner lining of blood vessels inside the eye that can lead to vision damage and/or loss," says Jonathon Ross, O.D., assistant clinical professor at The Ohio State University College of Optometry. "Thus, it is important for patients with diabetes to establish care with an eye doctor to monitor for diabetic eye disease."
Research on people with diabetes who took semaglutide has found that the medication does not appear to cause diabetic retinopathy. It also didn’t find that semaglutide makes diabetic retinopathy worse in people who already have the condition. Historically, though, there has been a link between people with diabetes losing weight and having a temporary worsening of diabetic retinopathy—regardless of what medication they take, if any, Dr. Krauss says.
Overall, Dr. Rizzo says that more research needs to be done to look into the connection between NAION and semaglutide. “This study gives us new information to consider,” he says.
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