European regulators have issued a warning that Novo Nordisk’s popular weight-loss and diabetes medications — Wegovy, Ozempic, and Rybelsus — may be associated with a rare but serious eye condition that could lead to vision loss.

The European Medicines Agency (EMA) safety committee announced that non-arteritic anterior ischemic optic neuropathy (NAION), a condition that causes damage to the optic nerve, may in very rare instances occur in people taking semaglutide, the active ingredient in all three drugs. The agency cited findings suggesting that NAION may affect up to 1 in 10,000 people who use the drug for at least a year.

While previous studies had linked semaglutide — particularly in Ozempic — to NAION in type 2 diabetes patients, this marks the first time a regulatory body has officially confirmed the potential side effect. NAION is the second-most common cause of optic nerve-related blindness after glaucoma.

Semaglutide-based drugs have surged in popularity globally as tools for managing obesity and diabetes. Wegovy and Ozempic are often prescribed for weight loss and blood sugar control, and Rybelsus is an oral version used primarily for diabetes treatment.

A recent study, reported by CNBC, also linked the drugs to potential eye complications. However, Novo Nordisk pushed back against the findings, citing what it called “key methodological limitations” in the research. Despite the concerns, market reaction has been minimal. Novo Nordisk shares dipped slightly in early trading Thursday before recovering to gain 0.1% by mid-morning in London.

One healthcare analyst downplayed the long-term impact of the news, calling it “hardly a game-changer.” The worst-case scenario, the analyst said, would likely be limited to a revised warning label on the drug’s packaging.

The EMA did not recommend halting the use of semaglutide-based medications but emphasized the importance of raising awareness among healthcare providers and patients.