Wegovy Pill and NAION Risk: What You Need to Know
In February 2026, the MHRA updated its safety advice on non-arteritic anterior ischaemic optic neuropathy, or NAION, a rare but serious eye condition that has been discussed in relation to GLP-1 medicines, including oral semaglutide. This page explains the condition, the warning signs, and what to do if you notice vision changes.
What is NAION?
NAION is a sudden loss of blood flow to the optic nerve. It can affect one eye and may cause blurred vision, a missing patch in your sight, or sudden loss of vision. It is a medical emergency.
People with high blood pressure, diabetes, high cholesterol, or previous eye disease may already have a higher background risk. That does not mean NAION will happen, but it does mean changes in vision should be taken seriously.
What the MHRA said
On 5 February 2026, the MHRA published updated guidance on NAION and GLP-1 receptor agonists. The advice is to stay alert to symptoms and arrange urgent eye care if they appear. The UK Yellow Card scheme remains the right place to report suspected side effects.
Symptoms that need urgent attention
- Sudden blurring or loss of vision in one eye
- A dark area, shadow, or missing patch in your vision
- Sudden change in colour vision
- Eye pain, especially if it appears suddenly
- Flashing lights or other sudden visual disturbance
If any of these happen, seek urgent eye care without waiting for a routine appointment.
What to do if you are concerned
If you have a history of eye disease or other vascular risk factors, mention them to your prescriber before starting treatment. If symptoms appear while you are taking Wegovy pill, tell an eye specialist, tell your prescriber, and report the event to Yellow Card if NAION is diagnosed or suspected.
The short version
NAION is rare, but it is serious. Most people taking Wegovy will not experience it. The sensible approach is simple: know the warning signs, act quickly if they appear, and keep your prescriber informed.
Read more Wegovy pill side effects and check the eligibility guide.