Hundreds of consumers are pursuing legal actions against manufacturers of GLP-1 receptor agonists, alleging these medications might elevate the risk of a rare vision loss condition. The Wall Street Journal reported that patients claim the drugs caused nonarteritic anterior ischemic optic neuropathy (NAION), a rare condition where blood flow to the optic nerve is suddenly reduced, leading to sudden vision loss.
Medications and Their Alleged Risks
NAION is the leading cause of acute optic nerve injuries among adults over 50, as described by the American Academy of Ophthalmology and the National Eye Institute, commonly referred to as an “eye stroke.” Dr. Douglas Lazzaro, an ophthalmologist at NYU Langone Health, highlighted to Fox News Digital that there is no current treatment for NAION, which can result in significant vision loss.
The lawsuits target Novo Nordisk, makers of Ozempic and Wegovy, and Eli Lilly, makers of Mounjaro and Zepbound. Both companies have challenged the claims. Novo Nordisk dismissed the lawsuits as baseless, referencing company-funded research that did not find an increased risk of NAION. Eli Lilly stated it continuously monitors safety data, maintaining current studies haven’t proven GLP-1 medications cause the condition.
Current Research and Findings
Research primarily focuses on semaglutide, rather than tirzepatide. A data analysis published in JAMA Ophthalmology in 2025 studying 37 million adults found users of semaglutide had a modest increase in NAION risk compared to users of SGLT2 inhibitors, another diabetes medication type.
A 2024 study by Harvard Medical School, also in the same journal, revealed that patients with type 2 diabetes on semaglutide faced roughly a fourfold higher relative risk of developing NAION, though the absolute risk remains low. Both studies, being observational, did not prove the medications caused NAION.
The FDA is reviewing evidence regarding a possible link between semaglutide and NAION but has not concluded a causation nor issued safety warnings. Meanwhile, the European Medicines Agency found enough evidence to suggest adding NAION as a “very rare” adverse reaction to semaglutide products in Europe.
Understanding NAION
NAION typically results in sudden, painless vision loss in one eye. Symptoms might include blurred vision, loss of peripheral vision, or decreased color vision, often developing after waking in the morning. Common risk factors include age, diabetes, high blood pressure, high cholesterol, obstructive sleep apnea, and smoking. Many GLP-1 drug users have diabetes or obesity, which themselves are risk factors for NAION.
Vision loss from NAION is often irreversible, though some might regain partial vision over time. While the condition is rare, occurring in two to ten cases per 100,000 people annually, experts stress that patients should not discontinue prescribed GLP-1 medications without consulting their healthcare provider. Considering the medications’ proven benefits might outweigh potential vision risks, a healthcare provider’s guidance is crucial.
An important factor in NAION is what doctors call a “disc at risk,” regarding specific characteristics of the optic disc. Dr. Lazzaro advised patients with such conditions might avoid semaglutide.
Melissa Rudy, senior health editor at Fox News Digital, observes the slight increase in NAION risk with semaglutides but believes the health benefits may surpass the potential risks, recommending medication for patients without a “disk at risk.”