UK regulator links semaglutide to rare vision-loss condition NAION

Britain's Medicines and Healthcare products Regulatory Agency said on Feb. 5, 2026 that semaglutide — sold as Ozempic, Wegovy and Rybelsus — may very rarely be linked to a sudden vision-loss condition, and that product information for those medicines will be updated in the coming months ^[1][3].

NAION, or non-arteritic anterior ischemic optic neuropathy, happens when blood flow to the front portion of the optic nerve drops. It usually causes sudden, painless vision loss in one eye that patients often describe as blurring or cloudiness ^[1].

The MHRA said studies suggest semaglutide treatment may be "very rarely" associated with NAION, meaning it may affect up to 1 in 10,000 people taking the drug ^[1][3]. A European review of evidence from clinical studies, post-authorization reports and published literature found that semaglutide exposure in adults with type 2 diabetes may be tied to roughly a two-fold increase in the relative risk of developing NAION. The agency said that corresponds to about one additional person affected for every 10,000 treated per year ^[1].

The review was considered by the Pharmacovigilance Expert Advisory Group of the UK's Commission on Human Medicines. That group noted conflicting evidence in the literature but agreed with recommendations to update the product information for semaglutide products in the UK ^[1]. Other GLP-1 medicines were not included in that review, though the MHRA said it is reviewing evidence for an association with other GLP-1 agonists ^[1][3].

For context, the MHRA said estimates of NAION's background incidence vary widely. In people with type 2 diabetes, reported rates range from 11.4 to 82 per 100,000 person-years. In the general population, estimates run from 7.73 to 11.5 per 100,000 person-years among people 40 and older, 10.2 per 100,000 among those 50 and older, and 14.79 per 100,000 among those 60 and older ^[1].

In the UK, the Yellow Card reporting scheme received three spontaneous reports suggestive of NAION with semaglutide between the drug's first authorization in 2018 and Aug. 1, 2025. Over the past five years, roughly 10.2 million packs of semaglutide are estimated to have been dispensed ^[1][3]. The MHRA notes that a report to the scheme does not mean the medicine definitely caused the problem, only that the reporter suspected it may have ^[1].

The agency's advice to clinicians says patients who report sudden loss of vision, including partial loss, should be urgently referred for examination by an ophthalmologist, and that semaglutide should be discontinued if NAION is confirmed. The MHRA also noted that privately prescribed semaglutide may not appear in a patient's medical history, so clinicians should ask about semaglutide use when these symptoms appear ^[1].

"While the potential risk of NAION for patients prescribed semaglutide is extremely small, it is important that patients and healthcare professionals are alert to the associated symptoms," said Dr. Alison Cave, the MHRA's chief safety officer ^[3].

Why it matters for patients

The practical point from the UK action is timing. The MHRA advises that patients taking semaglutide who notice a change in eyesight — sudden impairment, or vision that worsens very quickly in one or both eyes — urgently attend eye casualty if available or A&E ^[1][3]. NAION symptoms can involve only one eye, which makes them easy to dismiss.

The measured risk is small. The MHRA put it at up to 1 in 10,000 users overall and about one extra case per 10,000 treated per year in the European analysis ^[1]. People with type 2 diabetes already face a higher background risk of NAION, and the MHRA lists smoking, high blood pressure and high cholesterol as additional risk factors ^[1]. The agency did not withdraw any product or say the benefits of semaglutide no longer outweigh its risks.

Where a person lives may shape what their prescriber tells them. A July 2026 roundup of international regulatory actions reported that the current US prescribing information for Ozempic, revised in May 2026, still does not include a warning about NAION, and that Australia's Therapeutic Goods Administration said in July 2026 that NAION warnings would be added there ^[2]. That roundup also notes the European Medicines Agency's Pharmacovigilance Risk Assessment Committee concluded NAION is a very rare side effect of semaglutide medicines, and that the World Health Organization has published on the topic ^[2].

What happens next

The MHRA said the Summary of Product Characteristics and Patient Information Leaflet for semaglutide products will be updated in the coming months to describe the NAION risk and to advise that patients reporting sudden vision loss be urgently referred for an eye examination. No specific date has been given ^[1]. The agency's review of evidence for other GLP-1 agonists is ongoing, with no timeline disclosed ^[1][3]. Whether or when US labeling may change has not been reported ^[2].