GLP-1 Drugmakers Face Lawsuits Over Alleged Risk of Vision Loss
GLP-1 medications have become widely used for the treatment of Type 2 diabetes and, increasingly, for weight management. Drugs such as Ozempic, Wegovy, Rybelsus, Mounjaro, and Zepbound have attracted significant attention because of their effects on blood sugar, appetite, and body weight. Now, some of the manufacturers behind these medications are facing lawsuits alleging a possible connection between GLP-1 drugs and a rare eye condition that can cause sudden vision loss.
The condition at the center of the litigation is called non-arteritic anterior ischemic optic neuropathy, commonly known as NAION. It occurs when blood flow to part of the optic nerve is disrupted, potentially resulting in sudden vision loss. The condition is sometimes referred to as an "eye stroke."
Hundreds of GLP-1 Vision Loss Lawsuits
According to litigation data compiled from federal court records, 216 actions were pending in the federal multidistrict litigation involving GLP-1 medications and NAION as of the Judicial Panel on Multidistrict Litigation's September 1, 2026 report. The cases are centralized in the U.S. District Court for the Eastern District of Pennsylvania under MDL No. 3163.
The lawsuits involve allegations concerning several GLP-1 medications, including Ozempic, Wegovy, Rybelsus, Mounjaro, and Zepbound. Plaintiffs generally allege that the medications caused or contributed to NAION and that manufacturers failed to provide adequate warnings about the potential risk.
Separate litigation is also proceeding in New Jersey. A New Jersey court has established a multicounty litigation involving NAION claims associated with Ozempic and Wegovy. Law firm Weitz & Luxenberg has reported filing numerous cases against Novo Nordisk on behalf of individuals who allege that they developed NAION after using the medications.
It is important to note that filing a lawsuit does not establish that a medication caused an injury. The allegations will be evaluated through the legal process, and manufacturers can contest the claims.
What Is NAION?
NAION is a disorder involving the optic nerve, which carries visual information from the eye to the brain. The condition generally develops suddenly and often affects one eye. Vision loss can range from relatively mild to substantial.
The American Academy of Ophthalmology describes NAION as an optic nerve disorder associated with reduced blood flow. Established risk factors can include diabetes, high blood pressure, smoking, and other vascular factors.
NAION can be difficult to study because people who take GLP-1 medications may already have medical conditions that are associated with an increased risk of the condition. Type 2 diabetes itself, for example, can increase the risk of NAION.
What Does the Research Say About GLP-1 Drugs and Vision Loss?
The scientific evidence surrounding GLP-1 medications and NAION has developed rapidly.
The European Medicines Agency's safety committee reviewed available evidence involving semaglutide, the active ingredient in Ozempic, Wegovy, and Rybelsus. In 2025, the agency concluded that NAION should be classified as a "very rare" side effect of semaglutide. The EMA stated that the available evidence suggested approximately one additional case per 10,000 person-years of treatment.
The EMA also noted that several large epidemiological studies found an approximately two-fold increase in the relative risk of NAION among adults with Type 2 diabetes who were exposed to semaglutide. However, the absolute risk remained very low.
Regulators in the United Kingdom have also issued safety advice. The UK's Medicines and Healthcare products Regulatory Agency said in February 2026 that NAION had been very rarely reported in association with semaglutide and advised urgent ophthalmological assessment for patients experiencing sudden vision loss while receiving treatment.
At the same time, medical experts have emphasized that the evidence is not definitive for the broader GLP-1 drug class.
A 2026 consensus statement from the American Academy of Ophthalmology and the North American Neuro-Ophthalmology Society said that many studies report a small possible increase in NAION among patients using GLP-1 receptor agonists, while other studies have found no correlation. The organizations also said that the overall magnitude of the risk remains low and highlighted limitations in much of the available observational research.
This distinction is important. Evidence suggesting an association does not automatically demonstrate that a medication directly causes the condition in an individual patient.
What About Ozempic, Wegovy, Mounjaro and Zepbound?
Ozempic, Wegovy, and Rybelsus contain semaglutide and are manufactured by Novo Nordisk. Mounjaro and Zepbound contain tirzepatide and are manufactured by Eli Lilly.
The strongest regulatory action concerning NAION so far has involved semaglutide. The EMA recommended adding NAION to the product information for semaglutide medicines as a very rare adverse reaction.
The litigation, however, includes allegations involving multiple GLP-1 medications. Federal court information confirms that the current multidistrict litigation includes claims involving several GLP-1 receptor agonists and focuses on alleged NAION injuries.
Whether the evidence ultimately establishes a similar risk across different drugs remains an important question for researchers, regulators, doctors, patients, and the courts.
What Patients Should Know About Sudden Vision Changes
Patients taking a GLP-1 medication should not ignore sudden or rapidly worsening changes in vision.
The EMA advises patients receiving semaglutide to contact a doctor without delay if they experience sudden loss of vision or rapidly worsening eyesight. If NAION is confirmed, the agency recommends stopping semaglutide.
UK regulators similarly advise urgent ophthalmological assessment when sudden vision loss occurs during semaglutide treatment.
Patients should speak with their prescribing clinician before making decisions about stopping or changing a medication unless they are experiencing an emergency requiring immediate medical attention.
What Happens Next?
The GLP-1 NAION litigation is still developing. The federal cases have been centralized for coordinated proceedings, but a centralized proceeding does not mean that the allegations have been proven. The cases will involve questions about causation, warnings, scientific evidence, individual medical histories, and the manufacturers' knowledge of potential risks.
Meanwhile, researchers and regulators continue to evaluate evidence concerning GLP-1 medications and eye health.
For patients, the situation highlights the importance of discussing both the benefits and potential risks of treatment with a qualified healthcare professional. People with diabetes, obesity, high blood pressure, or other underlying conditions may have individual risk factors that need to be considered when choosing a medication.
The emerging evidence also demonstrates why drug safety information can change over time. Regulatory agencies may update warnings as new evidence becomes available, while courts assess individual claims under legal standards that are separate from regulatory decisions.
Sources
- European Medicines Agency, "PRAC concludes eye condition NAION is a very rare side effect of semaglutide medicines Ozempic, Rybelsus and Wegovy."
- U.S. District Court for the Eastern District of Pennsylvania, MDL No. 3163.
- American Academy of Ophthalmology and North American Neuro-Ophthalmology Society, 2026 consensus statement on GLP-1 receptor agonists and NAION.
- UK Medicines and Healthcare products Regulatory Agency, semaglutide and NAION safety update.
- Settlement Record, September 2026 litigation data.
Disclaimer
This article is provided for general informational purposes only and does not constitute medical, legal, or financial advice. The lawsuits discussed above contain allegations that have not necessarily been proven in court. Regulatory findings, scientific evidence, court proceedings, and drug labeling can change as new information becomes available. Patients should consult a qualified healthcare professional about their individual medical circumstances and should seek urgent medical attention for sudden or significant vision loss.