US Lawsuits Allege Link Between GLP-1 Drugs and Rare Vision Loss

Dozens of people in the United States have filed lawsuits against the manufacturers of Ozempic, Wegovy, Mounjaro and Zepbound, alleging that the medicines caused a rare eye condition that can lead to permanent vision loss.

The cases concern nonarteritic anterior ischemic optic neuropathy, or NAION. The condition occurs when blood flow to the optic nerve is reduced, causing sudden and usually painless loss of vision. It is considered rare and is sometimes described as an eye stroke.

The alleged connection between the medicines and NAION has not been established. Research findings remain mixed, and US regulators have not added a NAION warning to the medicines.

Lawsuits target two drugmakers

Ozempic and Wegovy are made by Novo Nordisk, while Mounjaro and Zepbound are manufactured by Eli Lilly. Reports cited in the case have said that more than 90 lawsuits against Novo Nordisk were filed in a New Jersey state court since 2025.

Patients represented by Weitz & Luxenberg are among those pursuing claims. A Pennsylvania woman who filed a lawsuit told The Washington Post that her vision became like looking through a “fishbowl” after she began taking medication for diabetes.

The lawsuits allege that the medicines caused NAION. However, the allegations have not been independently established.

Novo Nordisk has rejected the claims. A company spokesperson, speaking to The Wall Street Journal, said the lawsuits lacked merit and that the company was vigorously defending itself.

Eli Lilly has said it was reviewing available data on potential health risks. The company has not commented on the litigation.

Evidence remains inconclusive

Millions of people in the United States have reportedly turned to GLP-1 medicines to treat diabetes or manage obesity. Researchers have examined a possible association with NAION for several years.

Some studies have reported a possible increase in the risk of NAION among people taking GLP-1 medicines. Other research has found no significant association.

A Novo Nordisk-funded study based on randomised clinical trials found no evidence that GLP-1 medicines increase the risk of NAION. Dr Tina Vilsboll, a senior medical officer at Novo Nordisk and the study’s lead author, said the research found “no causality” and no indication that NAION should be considered a major concern for patients taking the medicines.

The North American Neuro-Ophthalmology Society and the American Academy of Ophthalmology have acknowledged reports suggesting a possible small increase in risk, while noting that other studies found no correlation. The organisations said the overall risk remains low.

The European Medicines Agency has estimated that NAION could affect up to one in 10,000 people with diabetes who use GLP-1 medicines. Researchers cited in reports have generally identified cases between six and 18 months after treatment began.

Regulatory review continues

The US Food and Drug Administration began examining a possible connection between GLP-1 medicines and NAION after initial reports emerged in 2024. No NAION warning has been added to the medicines by US regulators.

For now, the lawsuits are proceeding alongside continuing scientific and regulatory scrutiny. The available evidence does not establish that GLP-1 medicines cause NAION, and the possible association remains under examination.