Researchers Just Linked This Rare Vision Loss Condition to GLP-1s—Should You Be Concerned?

4 min readNew research links GLP-1s with a rare cause of blindness.This isn’t the first study to find a connection.Doctors stress that the complication is very rare, making it difficult to know what’s behind this.For all the good that GLP-1s bring, there are still reports that pop up here and there of potential downsides to keep in mind. There’s one in particular that’s admittedly scary: New research has found a link between GLP-1 use and a higher risk of developing a rare but serious condition that leads to vision loss.It’s called non-arteritic anterior ischemic optic neuropathy (NAION), and a new study published in the journal Neurology isn’t the first time this connection has been flagged. It’s important to stress that NAION is rare, and that the findings don’t mean that GLP-1s cause blindness—just that there’s a link.But because it’s important to have all of the information on any medications you may be taking, this is one more thing to at least know about. So why might GLP-1s be linked with vision loss and, more importantly, how worried about this should you be? Doctors break it down.Meet the experts: Bavand Youssefzadeh, DO, an ophthalmologist at Cedars Sinai and Global Lasik and Cateract Institute in Huntington Beach, California; Mir Ali, MD, medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CaliforniaWhat did the study find?For the study, researchers analyzed data from nearly 1.6 million patients who participated in five studies. Of those, 682,456 participants used semaglutide (Ozempic, Wegovy) and 911,098 used other medications.The researchers found that people who used semaglutide had a 152 percent higher risk of developing NAION compared with those who used other drugs. When they looked at patients who had diabetes, the researchers found that those who took semaglutide had a 141 percent higher risk of developing NAION compared to those who took other medications.Those sound like terrifying odds, but the actual numbers are slightly less freaky. Overall, there were 118 cases of NAION per 100,000 semaglutide users, which translates to less than a fraction of a percent of all people who used the medications. In people with type 2 diabetes, the actual number of cases was 125 cases per 100,000 semaglutide users.While none of these numbers are ideal, they translate to a very small number of people who used these medications. “Semaglutide significantly increases risk of NAION relative to non–GLP-1 receptor agonists, particularly among patients with diabetes,” the researchers wrote in the study’s conclusion. “These findings warrant further investigation and should inform clinical risk-benefit discussions.”This isn’t the first study to link NAION with GLP-1s. Research published in JAMA Ophthalmology in 2024 found that while overall cases of NAION in GLP-1 users were low, 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. When the researchers specifically looked at people who had overweight or obesity, those odds shot up to making them seven times more likely to be diagnosed with NAION.As we mentioned above, NAION is a rare condition, but it’s the second-leading cause of optic nerve blindness, per Brigham and Women’s Hospital. It’s believed to be caused by reduced blood flow to the optic nerve head, which is a crucial part of your vision. NAION is more common in people with diabetes, high blood pressure, and sleep apnea.The condition can come on suddenly, and it can lead to permanent vision loss, per the American Academy of Ophthalmology (AAO). There are no effective treatments for it.What’s behind the link?That’s not entirely clear. “NAION happens when the optic nerve does not receive enough blood flow,” says Bavand Youssefzadeh, DO, an ophthalmologist at Cedars Sinai and Global Lasik and Cateract Institute in Huntington Beach, California. “Most patients who develop it already have risk factors such as diabetes, high blood pressure, sleep apnea, or a crowded optic nerve.” Meaning, people who tend to be good candidates for GLP-1s are already at a higher risk for NAION.“We still don’t know whether GLP-1 medications directly cause NAION,” Youssefzadeh says. “One possibility is that dehydration, lower blood pressure or rapid changes in blood sugar could temporarily affect circulation to the optic nerve,” he says.Mir Ali, MD, medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, California, also agrees that doctors just don’t know what’s behind this.“The challenge is that many patients taking these medications already have conditions that put them at higher risk, so it can be difficult to separate the effect of the drug from the patient’s underlying health,” Youssefzadeh says.How concerned should you be?Doctors say there’s no need to panic. “It’s a very, very low-risk complication,” Dr. Ali says. “These medications have been around for diabetes much longer than they have for weight loss. Nobody has recommended stopping these medications for patients with diabetes or high blood pressure.”Youssefzadeh says it’s important for doctors and patients to be aware of the risks, but caution not to freak out or stop treatment. “NAION can cause permanent vision loss, so we have to take the concern seriously,” he says. “At the same time, it appears to be very rare.”Ultimately, Dr. Ali recommends putting the risk into perspective. “The overall takeaway is that the risk is very low, but the benefits of these medications are far greater,” he says.