Patients in the United States are initiating legal action against popular GLP-1 drugs, Ozempic, Wegovy, Mounjaro, and Zepbound, amid concerns over a rare but serious eye condition, nonarteritic anterior ischaemic optic neuropathy, raising safety questions about the diabetes and weight-loss treatments.
Patients taking popular GLP-1 weight-loss and diabetes medicines are facing a new wave of litigation in the United States, after dozens of lawsuits alleged the drugs were not properly labelled for a rare form of sudden vision loss. The condition, known as nonarteritic anterior ischaemic optic neuropathy, or NAION, can cause abrupt and usually painless loss of sight in one eye, and the damage may be permanent.
The drugs at the centre of the claims include semaglutide-based treatments Ozempic and Wegovy, made by Novo Nordisk, and tirzepatide products Mounjaro and Zepbound, made by Eli Lilly. According to ABC News, plaintiffs say they were not warned about the risk. Novo Nordisk has said the cases are without merit, while Eli Lilly says it continues to review safety information with regulators.
The evidence behind the concern is still unsettled. A Boston health system study published in 2024 raised the possibility of a link between semaglutide prescriptions and NAION, but subsequent research has not produced a consistent answer. Some studies have suggested a small increase in risk, while others have found no clear association. That uncertainty matters because many GLP-1 users already have diabetes or obesity, both of which can affect eye and cardiovascular health, making it difficult to prove that a drug, rather than an underlying condition, caused the injury.
Regulators have not all responded in the same way. The US Food and Drug Administration has identified NAION as a potential safety signal for several GLP-1 medicines, which means the issue deserves closer review but is not proof of causation. By contrast, the European Medicines Agency has classified NAION linked to semaglutide as a “very rare” side effect, putting the estimated risk at up to one case per 10,000 users and prompting updates to product information. Australia has also revised warnings for GLP-1 medicines. The different approaches do not necessarily mean one authority is wrong; they may simply be weighing the evidence differently or applying different labelling standards.
Eye specialists say the overall risk still appears low, but the symptom pattern is serious enough that sudden visual changes should never be ignored. People who notice a dark patch in their field of vision or an unexplained fall in sight should seek urgent medical help. Doctors generally advise against stopping a prescribed GLP-1 drug without first speaking to a clinician, because these medicines can help control blood sugar, support weight loss and, in some cases, lower cardiovascular risk. Anyone who has already experienced NAION should discuss the diagnosis with both an eye specialist and the prescriber before deciding on the next step.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
