A rare side effect can deserve urgent attention without making a medicine unsuitable for everyone. The semaglutide eye warning is a useful example: its seriousness and its frequency answer different questions.
What the regulators found
In June 2025, the European Medicines Agency’s safety committee concluded that non-arteritic anterior ischaemic optic neuropathy, or NAION, is a very rare side effect of semaglutide. The medicine is used in products including Ozempic, Rybelsus and Wegovy. The UK’s MHRA issued an eye-safety update on 5 February 2026.
NAION involves reduced circulation to the front of the optic nerve. It usually causes sudden, painless vision loss in one eye. Someone may notice blurring or a missing part of their vision rather than complete blindness. The absence of pain should never be reassuring when eyesight changes suddenly.
Two different ways to describe risk
EMA reported that several large studies in adults with type 2 diabetes suggested approximately twice the risk among semaglutide users. In absolute terms, that corresponded to about one additional NAION case per 10,000 people treated for a year.
“Twice the risk” is a comparison, not a prediction that many patients will lose their sight. The extra annual risk estimate is also different from the regulator’s “very rare” frequency category. Neither number gives an exact personal forecast.
Diabetes itself raises NAION risk. MHRA noted conflicting study findings while supporting an updated warning. Its review did not cover other GLP-1 medicines, so this finding should not automatically be applied to every drug in that family.
When to seek help
Sudden or rapidly worsening eyesight, including partial loss, needs urgent assessment at an eye emergency service or emergency department. Tell the team about all medicines, including privately prescribed semaglutide. If NAION is confirmed, regulators advise discontinuing semaglutide with clinical management.
If your vision is unchanged, discuss concerns with your prescriber rather than adjusting treatment yourself. Ask what benefit the medicine offers for your condition, how your eye history affects the decision, and whom to contact if symptoms develop.
Keep the wider treatment picture in view
NAION is separate from diabetic retinopathy, another eye problem addressed in Ozempic prescribing information. A medication review should also cover other important warnings. For example, severe, persistent abdominal pain, sometimes spreading to the back, requires urgent assessment for possible pancreatitis.
Use the patient leaflet supplied with your own product. UK, European and US information can provide useful context, but local indications and labelling may differ. This article provides general education, not an individual prescribing recommendation.
Image: illustrative AI-generated artwork; not a clinical photograph.
References
- EMA: semaglutide and NAION, June 2025 — Retained original reference.
- MHRA: semaglutide eye warning, February 2026 — Retained original reference.
- US Ozempic prescribing information, DailyMed, July 2026 — Retained original reference.
- MHRA: GLP-1 patient information — Retained original reference.
- MHRA: strengthened pancreatitis warnings, January 2026 — Retained original reference.
