European regulators raise concerns about eye stroke risk with GLP-1 drugs

European regulators have flagged nonarteritic anterior ischemic optic neuropathy (NAION), a rare "eye stroke" condition, as a potential side effect of semaglutide. While United States labels for Ozempic and Wegovy lack this warning, a JAMA Network Open cohort study of 1.5 million patients indicates a small but elevated risk of optic nerve disorders for those on semaglutide or tirzepatide. Consequently, manufacturers Eli Lilly and Novo Nordisk face a surge in federal multidistrict litigation, with eye injury cases rising to 247 by October 2026.

European regulatory warnings

• ▪The European Medicines Agency's current warning regarding nonarteritic anterior ischemic optic neuropathy applies only to semaglutide.
• ▪The European Medicines Agency raised concerns in 2025 about nonarteritic anterior ischemic optic neuropathy (NAION) as a very rare potential adverse effect of semaglutide.

Prevalence and incidence of NAION

• ▪Nonarteritic anterior ischemic optic neuropathy (NAION) is a rare condition that may affect about 1 in 10,000 people.
• ▪In the United States, the annual incidence of NAION is estimated at 2.3 to 10.2 per 100,000 among individuals over age 50 and 0.54 per 100,000 across all ages.

JAMA Network Open study findings

• ▪In the JAMA Network Open study, 35 patients (0.04%) in the semaglutide or tirzepatide group developed NAION, compared with 19 patients (0.02%) in the comparison group.
• ▪A cohort study published in JAMA Network Open found that patients with type 2 diabetes prescribed semaglutide or tirzepatide had a small but increased risk of developing NAION.
• ▪The JAMA Network Open cohort study analyzed electronic health records of over 1.5 million adults with type 2 diabetes spanning December 2017 to January 2023.

Ophthalmology consensus statement

• ▪The American Academy of Ophthalmology Board of Trustees and the North American Neuro-Ophthalmology Society issued a joint consensus statement in May 2026 noting mixed research findings on NAION risk.
• ▪The American Academy of Ophthalmology Board of Trustees and the North American Neuro-Ophthalmology Society noted that most patients with nonarteritic anterior ischemic optic neuropathy have a small or crowded optic disc.

Expert clinical advice

• ▪Rudrani Banik, MD, advised ophthalmologists to keep reports of nonarteritic anterior ischemic optic neuropathy in mind when treating patients taking GLP-1 drugs.
• ▪Rudrani Banik, MD, stated that patients should not stop taking GLP-1 drugs because of NAION reports but should discuss any concerns with their physicians.

Status of United States warning labels

• ▪To date, United States labels for the semaglutide products Ozempic and Wegovy do not contain information about nonarteritic anterior ischemic optic neuropathy (NAION).
• ▪Attorneys representing plaintiffs in product liability cases argue that adding a warning to United States labels would prompt clinicians and patients to consider the potential risk of NAION.

Product liability lawsuits over GLP-1 drugs

• ▪As of October 2026, the federal multidistrict litigation MDL-3163 included 247 cases involving alleged eye injuries associated with GLP-1 drugs, up from 29 cases in January 2026.
• ▪As of October 2026, the related federal multidistrict litigation MDL-3094 involving allegations of gastroparesis and other gastrointestinal injuries rose to 4,025 cases from 3,063 in January 2026.
• ▪Eli Lilly and Novo Nordisk have disclosed in investor filings that they face numerous product liability lawsuits involving GLP-1 drugs in federal, state, and international courts.

Debatable claims

• ▪Current scientific evidence is sufficient to link GLP-1 drugs to NAION
• ▪GLP-1 manufacturers bear liability for not warning US patients about NAION
• ▪US regulators should require NAION warnings on GLP-1 drug labels
• ▪The potential risk of NAION outweighs the health benefits of GLP-1 drugs