Hundreds of consumers have filed lawsuits against manufacturers of GLP-1 receptor agonists, asserting these drugs might raise the risk of a rare vision loss condition. The affected patients claim the medications caused NAION (nonarteritic anterior ischemic optic neuropathy), as reported by The Wall Street Journal.
Understanding NAION
NAION is characterized by reduced blood flow to the optic nerve, resulting in sudden vision loss. The American Academy of Ophthalmology and the National Eye Institute label it as an ‘eye stroke,’ highlighting its prevalence as the leading cause of acute optic nerve damage in adults over 50.
“The issue with NAION is that no effective treatment exists,” said Dr. Douglas Lazzaro, an ophthalmologist at NYU Langone Health.
According to Dr. Lazzaro, NAION can lead to severe vision impairment.
Companies Facing Legal Action
Novo Nordisk, which produces Ozempic and Wegovy, and Eli Lilly, maker of Mounjaro and Zepbound, have denied the allegations in the WSJ report. Novo Nordisk deemed the lawsuits baseless, citing company-backed research that found no heightened risk of NAION from its medications. Eli Lilly stated it continues monitoring safety data and stressed that existing studies do not conclusively link GLP-1 medications to NAION.
Fox News Digital reached out to the companies for comments.
Current Research Findings
Several studies have primarily examined the drug semaglutide, not tirzepatide. In 2025, a study published in JAMA Ophthalmology analyzed data from 37 million adults, revealing a modest increase in NAION risk among semaglutide users compared to those on SGLT2 inhibitors, another type of diabetes medication.
A 2024 Harvard Medical School study found that type 2 diabetes patients prescribed semaglutide had about a fourfold higher relative risk of developing NAION; however, the absolute risk remains low.
Both studies’ authors emphasized the need for further evidence, as the research was observational and the medication’s role in causing NAION cannot be proven.
Regulatory Insights
The FDA is assessing existing data on the possible link between semaglutide and NAION. The agency has not determined that semaglutide results in NAION and has not issued safety warnings for the drug.
Conversely, the European Medicines Agency concluded evidence suggests adding NAION as a ‘very rare’ side effect in semaglutide product information in Europe.
NAION Symptoms and Risk Factors
The AAO states NAION often results in sudden, painless vision loss in one eye. Additional symptoms include blurred or diminished vision, reduced peripheral vision, and decreased color vision. Symptoms often arise upon waking in the morning.
Among those using GLP-1 drugs, diabetes, obesity, high blood pressure, and high cholesterol are substantial risk factors. Observational studies struggle to separate diabetes effects from those of medication.
Experts stress patients should not discontinue prescribed GLP-1 drugs without consulting their healthcare provider. For many with diabetes or obesity, the drug’s benefits may outweigh potential vision risks.
Expert Advice
“If I find a ‘disc at risk’ – a densely packed optic nerve – during an exam, I would advise the patient not to use semaglutide,” Dr. Lazzaro recommended.
Despite acknowledging a slightly increased NAION risk linked to semaglutides, Dr. Lazzaro believes the overall health advantages surpass the risks. He would recommend GLP-1 drugs for patients without a ‘disc at risk’.
Melissa Rudy, the senior health editor at Fox News Digital, encourages story tips at [email protected].