Semaglutide’s rare eye warning deserves attention. Understanding the numbers, and knowing when to seek help, can make the news less alarming.
Semaglutide is used in medicines for type 2 diabetes and weight management, including Ozempic, Rybelsus and Wegovy. Benefits and side effects vary with the product and the person. A serious complication can remain very uncommon overall.
What changed?
In June 2025, the European Medicines Agency concluded that non-arteritic anterior ischaemic optic neuropathy (NAION) is a very rare side effect of semaglutide. The UK regulator highlighted this possible complication on 5 February 2026. These are UK and European safety findings; they do not establish what Indian product labels say. [1] [2]
What is NAION?
NAION involves reduced blood flow to the front of the optic nerve. It usually causes sudden, painless vision loss in one eye. Pain is therefore not a reliable guide to urgency. Diabetes itself increases the risk; smoking, high blood pressure and high cholesterol are other risk factors. [2]
What do the numbers actually mean?
EMA describes the side effect as “very rare”: it may affect up to 1 in 10,000 people taking semaglutide. Separately, large studies in adults with type 2 diabetes suggested roughly double the relative risk compared with people not taking it. The estimated absolute increase was about one additional case per 10,000 person-years, equivalent to 10,000 people treated for one year. [1]
That additional-case estimate is not the total annual risk or a prediction for an individual. The frequency category and the annual excess-risk estimate describe different things. The MHRA also noted conflicting research findings. This review concerned semaglutide, so its conclusion should not automatically be applied to every GLP-1 medicine. [2]
A different eye issue: diabetic retinopathy
Diabetic retinopathy affects the retina and is separate from NAION. Ozempic’s US prescribing information warns about retinopathy complications and notes that rapid improvement in blood glucose can temporarily worsen retinopathy. Tell your prescriber about existing eye disease and ask what monitoring you need. [3]
The more common side effects
Nausea, vomiting, diarrhoea, constipation and abdominal discomfort are common digestive effects. Many are mild or short-lived, but persistent vomiting or diarrhoea can cause serious dehydration. Contact your healthcare team if symptoms persist or you struggle to keep fluids down. Do not adjust doses yourself to manage symptoms. [3] [4]
When to get urgent help
- Sudden vision loss, even partial, or rapidly worsening eyesight: go urgently to an eye emergency service or emergency department. Do not wait for a routine appointment. Tell the team you take semaglutide. If NAION is confirmed, regulators advise stopping treatment under clinical management. [1] [2]
- Severe abdominal pain that does not go away, especially if it spreads to your back: seek urgent medical attention, with or without vomiting. This may be pancreatitis. It should not be dismissed as ordinary stomach upset. Clinicians should stop treatment if pancreatitis is suspected; it should not be restarted if confirmed. [5]
Questions for your prescriber
If you have no new symptoms, discuss concerns rather than abruptly changing prescribed treatment because of a headline. Ask: How do the expected benefits compare with my risks? Does my eye history change the plan? Which symptoms require urgent care?
Sources and review date
- EMA: semaglutide and NAION, June 2025
- MHRA: semaglutide eye warning, February 2026
- US Ozempic prescribing information, DailyMed, July 2026
- MHRA: GLP-1 patient information
- MHRA: strengthened pancreatitis warnings, January 2026
Editorial/source check: 18 October 2026.
Medical disclaimer: General education only, not personalised medical advice or a complete list of side effects. Read your medicine leaflet and consult your clinician. Urgent symptoms need immediate assessment.
Featured image: Illustrative AI-generated image.
