GLP-1 receptor agonists, popular medications for diabetes and weight loss, are under scrutiny by European health officials for a possible connection to non-arteritic anterior ischemic optic neuropathy (NAION), a rare but serious condition that can cause blindness. Recent studies have suggested a potential association, prompting investigations to determine if a causal link exists.
Recent studies, including one published in JAMA Ophthalmology by researchers at Harvard Medical School and Mass Eye and Ear, have indicated a potential link between GLP-1 receptor agonists like semaglutide (found in Ozempic and Wegovy) and an increased risk of NAION. These studies compared patients taking semaglutide with those using other medications and observed a higher incidence of NAION in the semaglutide group.
NAION occurs due to reduced blood flow to the optic nerve, leading to sudden and often permanent vision loss. While the exact cause of NAION isn’t fully understood, established risk factors include age, high blood pressure, and sleep apnea.
Furthering these initial findings, two research teams at the University of Southern Denmark recently conducted studies examining the prevalence of NAION among Danish and Norwegian residents using semaglutide for diabetes. These studies, one published and one under peer review, also reported a higher risk of NAION in the semaglutide group, corroborating the earlier U.S. study.
Following these studies, the Danish Medicines Agency (DMA) has requested the European Union’s Pharmacovigilance Risk Assessment Committee (PRAC) to conduct a comprehensive review of the available data, including the Danish studies and adverse event reports, to determine if NAION is a genuine side effect of semaglutide.
While these observational studies suggest a possible link, they cannot definitively establish a cause-and-effect relationship. Further research, including placebo-controlled clinical trials and studies proactively tracking GLP-1 users, is necessary to confirm any increased risk.
It is important to note that even if a link is confirmed, the absolute risk of NAION remains likely small. NAION is a rare disorder, despite being the second most common cause of optic nerve-related blindness after glaucoma.
The Danish researchers estimated that for every 10,000 people treated with semaglutide annually, between 1.5 and 2.5 additional cases of NAION might occur if a causal link exists. The DMA has received 19 reports of potential semaglutide-linked NAION since July 2024.
For most eligible patients, the benefits of GLP-1 therapy likely outweigh the potential risk of NAION. Untreated or poorly managed diabetes can also lead to vision problems. However, given the severity of NAION, even a small increased risk warrants attention. Further research may identify additional risk factors and inform preventative strategies.
GLP-1 medications are known to have common side effects like nausea and constipation, which typically subside over time. While rare serious complications like gastroparesis have been reported, other suggested issues, such as an increased risk of suicide, have not been substantiated by subsequent research. Further investigation into the potential link between GLP-1 medications and NAION is crucial to ensure patient safety and inform treatment decisions.
