Medications containing semaglutide (Ozempic, Wegovy, Rybelsus), used for type 2 diabetes and obesity, are frequently discussed in the public press. Since 2025, a question has been raised: can these treatments damage vision? Here’s what we know, without alarmism or minimisation.
What the European agency concluded
The European Medicines Agency’s safety committee (PRAC) began reviewing the issue in January 2025, after observational studies suggested an increased risk. On 6 June 2025 it concluded that non-arteritic anterior ischaemic optic neuropathy (NAION) is a ‘very rare’ side effect of semaglutide and may affect up to 1 in 10,000 people taking these medicines. Data from clinical trials point in the same direction, with a slightly higher risk than with placebo.
Novo Nordisk, the manufacturer, argues that the data do not show a reasonably established causal link: the scientific debate is therefore not entirely closed. However, the agency recommends that the product information include NAION.
What is it?
NAION is a damage to the optic nerve, caused by a lack of blood supply, that causes sudden, painless vision loss, most often in one eye: a dark or blurry area in the visual field, vision loss upon waking. It occurs independently of any medication, particularly in people with hypertension, diabetes, sleep disorders (apnoea), or a small-calibre optic nerve.
What to do if you are being treated?
- Do not stop treatment on your own initiative: diabetes and obesity also have consequences for health and vision.
- Seek medical advice promptly if your vision suddenly deteriorates or worsens rapidly. The agency recommends contacting a doctor without delay and stopping semaglutide if NAION is confirmed.
- Inform your ophthalmologist about the treatment, especially if you have diabetes.
- Continue retinal monitoring if you have diabetes: screening for diabetic retinopathy remains essential (see retinal diseases).
Keep track
A “very rare” risk does not justify abandoning a useful treatment, but it does justify being aware of the warning signs. Patients who already have optic neuropathy or advanced glaucoma deserve a personalized discussion between the prescriber and the ophthalmologist.
Sources
- EMA – Le PRAC conclut que la NAION est un effet indésirable très rare du sémaglutide (6 juin 2025)
- The Pharmaceutical Journal – Eye disorder is a ‘very rare’ side effect of weight-loss drugs, concludes EMA review
Your ophthalmologist answers your questions during the consultation. For a sudden symptom or sudden loss of vision, seek advice promptly: see the eye emergencies page.