Wegovy and Ozempic: what the vision loss studies found

What the JAMA Ophthalmology study actually found, and what it did not

The study that sparked widespread concern was a retrospective cohort analysis, published in JAMA Ophthalmology in July 2024, led by researchers at Massachusetts Eye and Ear. It looked at medical records from a large US database and compared rates of NAION among people taking semaglutide against people taking other medicines for weight management or type 2 diabetes. In the group using semaglutide for weight management purposes, those on the medicine were roughly 7–8 times more likely to have received a NAION diagnosis than comparators not on semaglutide.

That sounds alarming. But the absolute numbers are important context. NAION is rare, estimated to affect around 2–10 people per 100,000 per year in the general population. In the study itself, the numbers of NAION cases were small, and the design was retrospective and observational. That means it can identify a pattern in existing records; it cannot establish that semaglutide caused those cases. Confounding factors (including pre-existing cardiovascular risk, diabetes and hypertension, which themselves raise NAION risk) were difficult to fully account for.

The researchers were clear about these limits in their own paper. They called for prospective, controlled studies before conclusions about causation could be drawn. That is the appropriate scientific response to an observational signal, and it is where the evidence sits today. A question our prescribers hear most weeks is whether this study means people should stop semaglutide, the honest answer is that regulators have not reached that conclusion, and the benefit-risk assessment for eligible patients remains positive under current guidance.

How UK regulators have responded to the NAION signal

Following the publication of the JAMA Ophthalmology study, the European Medicines Agency and the US Food and Drug Administration both announced reviews of the available data. In the UK, the MHRA (the body responsible for licensing medicines) monitors safety signals through its Yellow Card scheme and through international pharmacovigilance networks. As of mid-2026, the MHRA had not issued a Drug Safety Update specifically linking semaglutide to NAION or requiring changes to the UK product labelling for Wegovy or Ozempic on this basis.

That position is not complacency. It reflects the current weight of evidence: one retrospective study generating a hypothesis, not a confirmed causal association. Regulatory decisions about labelling changes require a consistent body of evidence, ideally including prospective data. The MHRA continues to accept reports through its Yellow Card reporting scheme, and clinicians and patients are encouraged to report any suspected side effects there, including any unexpected changes in vision.

If you are already taking semaglutide and have concerns about your eyes, the right step is to speak to your prescriber or GP, not to stop the medicine without advice. Stopping a GLP-1 medicine abruptly without clinical input carries its own risks, particularly for people managing type 2 diabetes or significant obesity.

What is NAION, and who faces elevated background risk?

Non-arteritic anterior ischaemic optic neuropathy occurs when blood flow to the optic nerve is suddenly reduced, causing damage that can lead to permanent vision loss in the affected eye. It is painless and typically affects one eye at a time. There is no proven treatment to reverse the damage once it has occurred, which is why urgent assessment matters, early review by an ophthalmologist can help monitor for involvement of the second eye.

Known risk factors for NAION include a specific optic disc anatomy sometimes called a "disc at risk", sleep apnoea, hypertension, diabetes, high cholesterol, and cardiovascular disease. Several of those conditions are also common in people who are candidates for GLP-1 medicines. This overlap makes it genuinely difficult to disentangle whether semaglutide raises risk independently or whether the patient group using these medicines simply carries higher background NAION risk.

For context on the broader semaglutide and vision evidence, the picture is still developing. Current NHS guidance on semaglutide covers established side effects (mainly gastrointestinal) while the NHS semaglutide medicines page advises patients to report any new or unusual symptoms to their doctor promptly. That remains the practical guidance while research continues.

What is licensed for weight management in the UK, and what nume does not dispense

This matters for readers landing here from a search about Ozempic specifically: Ozempic is a brand of semaglutide licensed in the UK for type 2 diabetes, not for weight management. Wegovy (a higher-dose semaglutide formulation) is the brand licensed for weight loss in the UK. The two are often confused in media coverage, which is why the distinction between Wegovy and Ozempic deserves a clear explanation.

For weight management purposes, the two medicines with UK licences are Wegovy (semaglutide) and Mounjaro (tirzepatide, a dual GIP and GLP-1 receptor agonist made by Eli Lilly). Both are prescription-only medicines. If you are researching weight-loss treatments and want to understand your options, our prescribers review every consultation personally, software does not make prescribing decisions at nume. Costs and what is included are set out on the Wegovy treatment pricing page, which also links to the Wegovy weight loss study findings we use to inform how we present expected outcomes to patients.

If you have a history of eye conditions, optic nerve problems, or any of the NAION risk factors mentioned above, that information should be part of your consultation, our prescribers factor it in. Check your eligibility and start a free consultation to have those questions answered by a real clinician.