GLP-1 Drugs Face Hundreds of Lawsuits Over Rare 'Eye Stroke' Linked to Vision Loss

Hundreds of consumers are suing the manufacturers of GLP-1 receptor agonists, alleging that the popular medications may increase the risk of a rare form of vision loss. The patients behind the lawsuits claim that these drugs, used for weight loss and type 2 diabetes management, caused nonarteritic anterior ischemic optic neuropathy (NAION), a condition also referred to as an "eye stroke."

NAION occurs when blood flow to the optic nerve is suddenly reduced, resulting in abrupt vision loss. It is the most common cause of acute optic nerve injury in adults over 50, according to the American Academy of Ophthalmology and the National Eye Institute.

"The problem with NAION is there’s no treatment," Dr. Douglas Lazzaro, an ophthalmologist at NYU Langone Health, told Fox News Digital. "So it can cause some very profound vision loss."

The lawsuits target Novo Nordisk, the maker of Ozempic and Wegovy, and Eli Lilly, the manufacturer of Mounjaro and Zepbound. Both companies have disputed the allegations.

Novo Nordisk stated that the lawsuits are without merit and cited company-funded research that found no increased risk of NAION associated with its drugs. Eli Lilly indicated that it continues to monitor safety data and maintains that current studies do not establish a causal link between GLP-1 medications and the condition.

Research on the link between GLP-1 drugs and NAION is ongoing. A 2025 JAMA Ophthalmology study analyzing data from 37 million adults found a modest increase in NAION risk among semaglutide users compared to those taking SGLT2 inhibitors, another class of diabetes medication. A 2024 Harvard Medical School study published in the same journal reported that patients with type 2 diabetes prescribed semaglutide had a roughly fourfold higher relative risk of developing NAION, though the absolute risk remained very low.

The authors of these studies noted that their research was observational and could not definitively prove that the medications caused NAION, emphasizing the need for more evidence. The U.S. Food and Drug Administration (FDA) is reviewing available data regarding a potential association between semaglutide and NAION but has not concluded that the drug causes the condition or issued a safety warning. The European Medicines Agency, however, has recommended adding NAION as a "very rare" adverse reaction to semaglutide product information in Europe.

Dr. Lazzaro acknowledged the difficulty in assessing statistical significance due to numerous confounding variables, such as patient obesity, sex, age, and hypertension. He noted that after attempting to control for these variables, studies still indicated a higher risk of NAION.

NAION typically manifests as sudden, painless vision loss in one eye, often accompanied by blurred or dim vision, loss of peripheral vision, or diminished color vision. Symptoms commonly appear upon waking in the morning. Key risk factors for NAION include age, diabetes, high blood pressure, high cholesterol, obstructive sleep apnea, and smoking. Experts point out that many individuals taking GLP-1 drugs have underlying conditions like diabetes or obesity, which are themselves risk factors for NAION, making it challenging to isolate the medication's impact.

Vision loss from NAION is frequently permanent, with no proven treatments to reverse optic nerve damage, although some partial vision recovery may occur over time. The condition is considered rare, affecting approximately two to 10 individuals per 100,000 annually, depending on the studied population.

Healthcare professionals advise patients not to discontinue prescribed GLP-1 medications without consulting their doctor, as the benefits for managing diabetes or obesity may outweigh potential vision risks for many. An ophthalmologist might advise a patient with a "disc at risk"—certain characteristics of the optic nerve that suggest a vulnerability—against using semaglutide. However, for most patients, particularly those without such a risk factor, the overall health benefits of GLP-1 medications are considered to outweigh the potential for NAION.