"Lost Vision After Wegovy and Ozempic: U.S. Patients File Lawsuits Over Sudden Sight Loss While Trying to Lose Weight"

“NAION Reported After GLP-1 Treatment” Claims
Causal Link Remains Unclear

In the United States, patients who experienced sudden vision loss after receiving glucagon-like peptide-1 (GLP-1) drugs for obesity or type 2 diabetes—such as Ozempic, Wegovy, and Zepbound—have filed a series of lawsuits against the pharmaceutical companies.

According to the Wall Street Journal (WSJ) on September 19 (local time), lawsuits are underway in the U.S. seeking damages from Novo Nordisk and Eli Lilly, alleging that GLP-1 medication triggered nonarteritic anterior ischemic optic neuropathy (NAION). NAION is a condition in which reduced blood flow to the optic nerve causes sudden vision loss, and the impairment is often permanent.

Novo Nordisk, a Danish pharmaceutical company, presents the type 2 diabetes treatment "Ozempic". Photo by AP Yonhap News

WSJ reported on the case of Michelle Pennell, a 53-year-old woman. While sitting at her desk, she suddenly felt heaviness in her right eye and her vision became blurry. She could see straight ahead, but her right and lower field of vision were impaired, making it feel as though she was looking through a fish tank. Two weeks later, her physician diagnosed her with NAION. She had reportedly been using Ozempic for about six months to treat type 2 diabetes.

An American personal injury law firm has filed more than 90 lawsuits after 2025 in New Jersey courts on behalf of patients who developed NAION after being prescribed Ozempic or Wegovy, targeting Novo Nordisk. In addition, lawsuits have been filed in the Philadelphia federal court, claiming that GLP-1 drugs caused NAION and that the companies did not adequately warn about the associated risks.

However, the causal relationship between GLP-1 drugs and NAION has not yet been clearly established. Some studies have found that the risk of NAION may be approximately twice as high in patients treated with semaglutide, the main ingredient in Ozempic and Wegovy, compared to a control group not taking the drug. However, because NAION itself is very rare, even if the risk doubles, it is estimated that only about two out of every 10,000 patients would develop NAION on average. Conversely, research from an ophthalmology institute found the risk could be nearly eightfold higher. According to these studies, NAION often occurred within the first 6 to 18 months after beginning GLP-1 treatment. In contrast, a large-scale study funded by Novo Nordisk found no evidence that GLP-1 drugs increase the risk of developing NAION.

Experts have pointed out that these inconsistent research results may come from differences in how NAION is classified among studies, as well as the fact that patients using GLP-1 drugs often already have underlying conditions—such as diabetes, cardiovascular disease, hypertension, or sleep apnea—which themselves are risk factors for NAION.

The U.S. Food and Drug Administration (FDA) began an investigation into the potential link between GLP-1 drugs and NAION in late 2024 after first confirming a possible connection, but has not added a relevant warning to product labeling yet. In contrast, in June of last year, the European Medicines Agency (EMA) classified NAION as a "very rare side effect" of semaglutide and recommended warning labels be added to product information in Europe. Similar warnings or information have been included in the United Kingdom, Japan, Australia, and New Zealand.

In Denmark, where Novo Nordisk is headquartered, 27 patients who developed NAION after receiving Ozempic or Wegovy were awarded over 1.5 million dollars (approximately 2.1 billion won) in compensation, with an additional 38 cases under review. This compensation comes from a government program for rare and serious drug side effects, where the Danish Patient Compensation Association, an independent body, evaluates claims. Novo Nordisk does not participate in this process. Both Novo Nordisk and Eli Lilly deny that a causal relationship between their drugs and NAION has been established, and are fighting the lawsuits.

Dr. John J. Chen, an optic nerve specialist at the Mayo Clinic, emphasized that patients must weigh their personal risk against the benefits of the medication. He noted that for people who need medication to manage diabetes or cardiovascular disease, the benefits may outweigh the risks, but the judgment could be different for those using them simply to lose a few kilograms.

Last year, the American Optometric Association recommended that patients starting GLP-1 drugs should undergo an ophthalmic exam to check the status of their optic nerves.

This content was produced with the assistance of AI translation services.