Published Nov 10, 2026 | 10:53 AM ⚊ Updated Nov 10, 2026 | 10:53 AM
Close-up of doctor holding ophthalmoscope examining male patient eyes in hospital medical examination room. (iStock)
The US Food and Drug Administration (FDA) has warned of a potential increased risk of a rare eye condition among people taking glucagon-like peptide-1 receptor agonists (GLP-1 RAs), a class of medicines widely prescribed for type 2 diabetes and weight management.
The condition, called non-arteritic anterior ischaemic optic neuropathy (NAION), can cause sudden, painless loss of vision in one eye and, in some cases, permanent vision impairment, the FDA said in a safety alert issued on 9 November.
The warning covers GLP-1 medicines, including semaglutide, sold under brand names such as Ozempic, Wegovy and Rybelsus. The FDA requires manufacturers of all GLP-1 RA medicines to include information about the potential risk in the Warnings and Precautions section of their product labels.
But what exactly is NAION, how does it affect vision, and what should people taking these medicines watch out for?
NAION is a condition in which blood flow to the front part of the optic nerve, known as the optic disc, is reduced.
The optic nerve carries visual information from the eye to the brain. When its blood supply is disrupted, the nerve can become damaged, affecting a person’s ability to see.
NAION typically causes sudden, painless vision loss in one eye. The loss may be partial or severe and can be permanent.
According to the FDA, the underlying cause of the condition “is not completely understood.”
One of the key warning signs is sudden, painless loss of vision in one eye. Some people may first notice the change when they wake up.
Other symptoms listed by the FDA include:
The agency has advised patients to contact their healthcare professional immediately if they experience any of these symptoms.
If NAION is suspected, the patient should be promptly referred to an ophthalmologist for evaluation.
GLP-1 receptor agonists mimic the action of a naturally occurring hormone called glucagon-like peptide-1. The hormone helps regulate blood glucose levels after meals and acts on parts of the brain that control appetite and food intake.
These medicines are used to treat type 2 diabetes and manage excess body weight. Certain drugs in the class also have approved uses related to cardiovascular risk, chronic kidney disease, obstructive sleep apnoea and metabolic dysfunction-associated steatohepatitis.
The FDA’s warning follows a review of clinical trial data, animal studies, post-marketing reports and observational research.
The agency said that although it identified limitations in an earlier study examining semaglutide and NAION, “further assessment of the potential increased risk for NAION was warranted.”
It subsequently evaluated evidence from several sources to assess whether there could be a relationship between GLP-1 medicine use and the eye condition.
The FDA conducted a meta-analysis of 126 randomised controlled clinical trials involving 134,253 participants. Of these, 78,217 received GLP-1 medicines, and 56,036 received comparator treatments.
The analysis identified 15 probable cases of NAION. Ten occurred among people taking GLP-1 medicines and five among those receiving placebo. No cases were identified among participants receiving other glucose-lowering medicines.
The incidence rate was 6.4 cases per 100,000 person-years among GLP-1 users, compared with 3.8 cases per 100,000 person-years among people receiving comparator treatments.
The agency also examined real-world data from adults with type 2 diabetes who started treatment with GLP-1 medicines, sodium-glucose cotransporter-2 (SGLT-2) inhibitors or dipeptidyl peptidase-4 (DPP-4) inhibitors between 2019 and 2024.
The incidence rates ranged from 26 to 32 cases per 100,000 person-years across the treatment groups. The agency did not find a statistically significant increase in NAION risk among GLP-1 users compared with SGLT-2 inhibitor users.
However, GLP-1 users had a higher risk compared with people taking DPP-4 inhibitors. The hazard ratio was 1.43, with a 95% confidence interval of 1.02 to 2.01.
The FDA said observational studies it reviewed also generally reported an increased risk among people with type 2 diabetes who started GLP-1 medicines compared with those who started DPP-4 or SGLT-2 inhibitors.
Summarising its assessment, the agency concluded: “… there is a potential increased risk of rare NAION events in patients taking GLP-1 RAs.”
The FDA identified several potential risk factors for NAION. These include:
People who have already experienced NAION in one eye also face an increased risk of the condition occurring in the other eye.
The FDA noted that these risk factors often overlap with conditions commonly found among people taking GLP-1 medicines. This overlap can make it difficult to establish whether the medicine itself contributed to an individual case.
The FDA’s warning applies to all GLP-1 receptor agonist medicines. These include:
Tirzepatide acts on both GIP and GLP-1 receptors.
The FDA said NAION cases had been reported for all currently marketed GLP-1 RA products.
The FDA has not advised all patients taking GLP-1 medicines to stop treatment.
Instead, it has asked patients and caregivers to be alert to symptoms such as sudden, painless vision loss, blind spots, blurred vision or other visual disturbances in one eye.
Patients who experience these symptoms should seek medical attention immediately. Those who have had a NAION event should discuss with their healthcare professional whether to continue or discontinue the medicine.
For patients who develop NAION, the agency has advised healthcare professionals to consider discontinuing the GLP-1 medicine unless the benefits of treatment clearly outweigh the risks.
The warning is a precaution based on the FDA’s assessment of available evidence. It does not mean that everyone taking semaglutide or another GLP-1 medicine will develop NAION, nor does it establish that these medicines directly cause the condition. Patients should not discontinue prescribed treatment without consulting their healthcare professional.
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(Edited by Fayisa CA)
