What you need to know about GLP-1s and your eyesight – in summary

• GLP-1 medications – the weight loss injections known by brand names such as Ozempic, Wegovy and Mounjaro are now very widely used. Some studies have linked semaglutide (the active ingredient in Ozempic and Wegovy) to a rare cause of painless vision loss called non-arteritic anterior ischaemic optic neuropathy (NAION). The UK MHRA and the European Medicines Agency classify NAION as a very rare side effect of semaglutide, affecting up to 1 in 10,000 users, equivalent to approximately 1 additional case per 10,000 patients treated per year.
• Taking a GLP-1 medication does not, by itself, rule out laser eye surgery or cataract surgery. Your eye health, if you have diabetes – your diabetes control, and the planned procedure all matter.
• Sudden loss of vision or rapidly worsening eyesight requires urgent same day assessment by your local optometrist, or at an eye casualty or emergency department regardless of if you are taking a GLP-1 medication or not. Do not wait for a routine optometrist appointment.

Over the past couple of years, GLP-1 medications – the weight loss and injections better known by brand names such as Ozempic, Wegovy and Mounjaro – have become part of everyday conversation. Along with them has come a run of headlines about GLP-1s and your eyesight, and a steady stream of questions in my clinic from people who are understandably concerned. Many of them are considering laser eye surgery or cataract surgery and want to know where they stand. Here is what the evidence actually shows and what it means if you are thinking about vision correction.

What eye problems have been linked to semaglutide?

The main recent concern is NAION (non-arteritic anterior ischaemic optic neuropathy), a condition caused by reduced blood flow to the front of the optic nerve. It typically causes sudden, painless loss or blurring of vision, usually in one eye. The UK MHRA and the European Medicines Agency classify NAION as a very rare side effect of semaglutide, affecting up to 1 in 10,000 users, equivalent to approximately 1 additional case per 10,000 patients treated per year.

Can I have laser eye surgery or cataract surgery if I’m on a GLP-1?

In almost all cases, yes. Taking a GLP-1 medication does not, in itself, rule you out of laser eye surgery or cataract surgery. Neither procedure is affected by the medication in the way people often assume. Both are carried out under local or topical anaesthetic (the eye is numbed and you stay awake throughout), so the questions around general anaesthesia that apply to some other operations generally do not arise here.

What genuinely matters is the same as it is for any patient: the health and stability of your eyes. At every consultation, I map the eye in detail and assess your retina carefully as part of that process. Very occasionally, a patient may have very poorly controlled diabetes, and in this situation it is often best that the diabetes is brought under control before the eye surgery to reduce the otherwise higher risk of complications. Paradoxically in this situation, a large and rapid improvement in blood glucose can sometimes initially worsen existing diabetic retinopathy. This has been observed with semaglutide and other treatments that substantially improve glucose control. Good glucose control remains important for protecting sight over the longer term and if you already have diabetic retinopathy, your diabetes and eye teams may arrange closer monitoring when treatment changes.

The one firm request I make is a simple one. Tell me, and your wider surgical team, about your health and every medication you take, including your GLP-1. It very rarely changes the plan, but complete information is what allows me to give you properly tailored advice.

My advice if you’re on a GLP-1 and worried about your vision

My guidance here is straightforward, and it is the same guidance I would give to anyone. If something about your vision feels off – blurring, a change in your field of view, or anything that comes on suddenly – do not ignore it, and do not simply assume it is the medication. A sudden loss of vision or rapidly worsening eyesight always requires urgent same day assessment by your local optometrist, or at an eye casualty or emergency department. Do not wait for a routine optometrist appointment.

For the vast majority of people, GLP-1 medications and good eye health sit together perfectly comfortably. If you are considering vision correction and happen to be taking one of these treatments, it need not stand in your way. It is simply one more thing to mention when we sit down together.

About Mr Alex Day

Mr Alex Day FRCOphth PhD CertLRS FWCRS is a Consultant Ophthalmic Surgeon at Moorfields Private, specialising in laser eye surgery (LASIK and SMILE), cataract surgery and Implantable Collamer Lens (ICL) surgery. Based in London, he is the author of over 70 peer-reviewed publications and is widely regarded as the surgeon of choice for medical practitioners and their families seeking vision correction in London. To arrange a consultation, visit www.alexday.co.uk.