The FDA on Nov. 9 told every maker of a GLP-1 receptor agonist to add a warning about non-arteritic anterior ischemic optic neuropathy, or NAION, the sudden and painless vision loss in one eye that is often called an eye stroke. The new language goes into the Warnings and Precautions section of the labels for Ozempic, Wegovy, Mounjaro and the rest of the drug class. The agency’s evidence is a pooled analysis of 126 trials in which probable NAION occurred at 6.4 per 100,000 patient-years on the drugs against 3.8 on comparators.
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The agency named no individual officials in its safety communication, and it framed the finding as a potential increased risk rather than a proven cause.
Twelve products named in the agency’s list
The FDA drug safety communication lists every approved product in the class, with approval years: Byetta (exenatide, 2005), Victoza (liraglutide, 2010), Trulicity (dulaglutide, 2014), Saxenda (liraglutide, 2014), Xultophy (liraglutide with insulin degludec, 2016), Soliqua (lixisenatide with insulin glargine, 2016), Ozempic (semaglutide, 2017), Rybelsus (semaglutide, 2019), Wegovy (semaglutide, 2021), Mounjaro (tirzepatide, 2022), Zepbound (tirzepatide, 2023) and Foundayo (orforglipron, 2026). Byetta’s application was voluntarily withdrawn for reasons unrelated to safety or effectiveness, so only generic exenatide is marketed. Tirzepatide also acts on the GIP receptor.
126 trials, 134,253 patients and 15 probable cases
The trial analysis covered 78,217 patients on GLP-1 drugs and 56,036 on comparators, adding up to 288,879 person-years of follow-up. Fifteen probable NAION events turned up: 10 in the GLP-1 groups, 5 on placebo and none on other glucose-lowering drugs. That works out to 6.4 versus 3.8 per 100,000 patient-years. For context, the agency cites a background rate of 2.3 to 10.2 cases per 100,000 people per year among adults over 50, which brackets both numbers and explains why the label language says potential.
Observational data from the FDA’s Sentinel system point the same way with less certainty. In adults with type 2 diabetes followed from 2019 to 2024, the hazard ratio for NAION against SGLT-2 inhibitors was 1.19 (95% confidence interval 0.91 to 1.54), not statistically significant. Against DPP-4 inhibitors it was 1.43 (1.02 to 2.01), a significant increase. Animal data did not identify any mechanism linking the drugs to the optic nerve.
Europe moved first and U.S. lawsuits followed the signal
European regulators reached this point in 2025. The European Medicines Agency’s safety committee concluded in June 2025 that NAION is a very rare side effect of semaglutide, meaning up to 1 in 10,000 users, with large studies in type 2 diabetes suggesting about a two-fold increase in risk. The World Health Organization followed with a medical product alert on June 27, 2025 noting that the condition is generally irreversible.
Earlier observational work produced larger numbers than the trial data. Healio’s report describes a 2024 JAMA Ophthalmology study of more than 16,000 patients at one center that found semaglutide users faced a four- to sevenfold higher NAION risk, particularly when taking it for weight loss, and a 2025 analysis of 14 databases covering more than 37 million people with type 2 diabetes that found only a modest increase, smaller than earlier reports. Messner noted that the first was a look-back study of high-risk patients at a tertiary center.
In the United States the issue reached courtrooms before it reached labels. Review of Optometry reported that plaintiffs sued Novo Nordisk and, to a lesser extent, Eli Lilly for failing to warn, that Novo called the suits without merit, and that the FDA was still studying the question through Sentinel. Harvard’s Aaron Kesselheim said the agency is typically conservative about label warnings. Some clinicians urge calm: Leonard Messner, an optometrist speaking at Academy 2026, told Healio that the absolute risk stays very low and that vigilance beats a knee-jerk response.
Specialists do not speak with one voice. John Chen of the Mayo Clinic told Review of Optometry that for patients taking GLP-1 drugs for diabetes or heart disease the benefits likely outweigh the risk, though the tradeoff looks different for modest weight loss. Raj Maturi of the American Academy of Ophthalmology said patients without symptoms should keep taking their prescribed medication and raise any concern with their primary care physician. The American Optometric Association has recommended since 2025 that people starting a GLP-1 drug get an eye exam.
NAION is the second most common optic neuropathy after glaucoma, and the WHO describes it as generally irreversible, which explains the weight regulators give a very rare event.
Instructions for patients, caregivers and prescribers
The agency tells patients to contact a health care professional right away for sudden, painless vision loss in one eye, blurred or missing vision, color distortion or blurry central spots. If NAION occurs, patient and clinician should discuss whether to continue the drug. Known risk factors include smoking, diabetes, high blood pressure, sleep apnea, anemia and kidney disease, and a person with NAION in one eye faces higher risk in the other. Prescribers are told to refer suspected cases to an ophthalmologist promptly and to consider stopping the drug unless the benefits clearly outweigh the risk.
Adverse events can be reported through MedWatch or by phone at 1-800-332-1088. The unresolved question is how much of the 6.4 versus 3.8 gap reflects the drugs themselves rather than the diabetes and weight problems of the people taking them, a distinction the pooled trial data cannot settle.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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