Lawsuits Claim Popular Weight-Loss Drugs Failed to Warn of Vision Risk

Patients say they were not properly warned about a rare condition tied to sudden sight loss.

An increasing number of people who say they developed serious vision problems after using widely prescribed weight-loss drugs are taking legal action against the companies behind them. The cases center on a rare disorder called nonarteritic anterior ischemic optic neuropathy, or NAION, sometimes referred to as an “eye stroke.” Those filing suit argue that manufacturers did not adequately disclose the possibility of permanent damage to eyesight. NAION affects the optic nerve and can trigger abrupt changes in vision, including severe loss of sight and, in some cases, blindness. It is uncommon and most often seen in people over 50.

The lawsuits target companies behind some of the most commonly used GLP-1 medications, which are prescribed for diabetes and weight management. A key allegation is that NAION does not appear on U.S. warning labels for these drugs, even though some other countries have included the condition in safety information. Novo Nordisk, the maker of Ozempic and Wegovy, revised European labeling in June to note a possible link between semaglutide and NAION. The updated warning said the condition could affect as many as one in 10,000 patients. Semaglutide is the active ingredient in both drugs.

Research on whether GLP-1 medications raise the risk of NAION has reached mixed conclusions. Some studies have pointed to a possible connection, while others have found no relationship. Earlier this year, the American Academy of Ophthalmology said the evidence was not strong enough to justify a broad warning and added that a direct cause-and-effect link had not been proven. That uncertainty is expected to remain central to the legal fight. The lawsuits focus on claims of inadequate warnings, but they do not prove that the medications caused the plaintiffs’ vision loss.

The drugmakers have denied the allegations and defended their products. Eli Lilly, which makes Mounjaro and Zepbound, said patient safety is its top priority. The company said it tracks and reports safety data to the U.S. Food and Drug Administration and regularly discusses potential concerns with regulators. Lilly also said it continues to evaluate available information, including data on eye-related conditions, and urged patients who experience side effects to consult medical professionals. Novo Nordisk also rejected the claims, calling the personal injury cases meritless and saying it will contest them.

Public attention has grown as access to GLP-1 medications has widened. In January, a Maryland truck driver filed a lawsuit claiming that an eye stroke left him blind after taking a GLP-1 drug. More recently, a federal initiative called Medicare Bridge expanded access to certain weight-loss medicines for older Americans. Federal officials said near the end of August that about 600,000 seniors had signed up for the program, which offered the drugs for $50 a month.

Medical officials have advised patients taking semaglutide who have not had vision symptoms to keep taking the medication rather than stopping it on their own. People considering these drugs and worried about NAION are being encouraged to speak with a healthcare professional about their individual risks before starting treatment.

The lawsuits account for only a small share of the people using GLP-1 medications, but they have raised broader questions about how new safety concerns should be communicated. As the research continues and the cases advance, patients, doctors, regulators, and manufacturers will be looking for clearer answers about whether these widely used drugs pose a real threat to vision.