The US Food and Drug Administration (FDA) has told makers of all GLP-1 receptor agonist medicines to add a warning to their labels about a possible link to a rare but serious eye condition that can cause permanent vision loss. In a drug safety communication issued on November 9, FDA said these drugs may be associated with non-arteritic anterior ischemic optic neuropathy (NAION), which occurs when blood flow to the optic nerve drops. It can cause sudden, painless loss of vision in one eye, and sometimes the damage is permanent. Manufacturers must now include this information in the “Warnings and Precautions” section of their product information.
The class covers some of the most widely prescribed drugs today, including semaglutide (Ozempic, Wegovy, Rybelsus), liraglutide (Victoza, Saxenda), dulaglutide (Trulicity) and tirzepatide (Mounjaro, Zepbound). They are mainly used for type2 diabetes and obesity, and some are also approved to lower heart and kidney risks.
The FDA reached its decision after reviewing clinical trials, animal studies, reports received after the drugs reached the market, and observational studies. A meta-analysis of 126 trials with 134,253 participants found 15 probable NAION cases. Ten were in people taking GLP-1 drugs and five were in those on placebo, while none appeared among people taking other non-GLP-1 diabetes drugs. The rate was 6.4 cases per 100,000 person-years for GLP-1 users, against 3.8 for those on comparison treatments.
The FDA also ran a real-world study of type 2 diabetes patients who started GLP-1 drugs between 2019 and 2024. Compared with patients on SGLT-2 inhibitors, it found no statistically significant rise in risk. Compared with those on DPP-4 inhibitors, however, the risk was higher. The FDA added that it had received NAION reports for every GLP-1 product on the market, and that several observational studies had consistently shown higher risk in diabetes patients starting these drugs than in those starting other treatments.
Even so, the FDA stressed that the evidence points to a possible increased risk and does not prove the drugs cause the condition. Its review of animal data also found no explanation for how these drugs might raise the risk.
Patients should seek immediate medical help if they have sudden, painless vision loss in one eye, blurred vision, blind spots, tunnel vision, distorted colours or reduced central vision. These symptoms may first be noticed on waking. Doctors have been asked to send anyone with suspected NAION quickly to an eye specialist, and to consider stopping the GLP-1 drug in those who develop it, unless the benefits of continuing clearly outweigh the risks. Patients who have already had an NAION episode should talk to their doctors about whether to continue the medicine.
NAION is rare in general. Published estimates put it at 2.3 to 10.2 cases per 100,000 people each year among adults over 50. Diabetes, high blood pressure, smoking, sleep apnoea, anaemia and kidney disease are known risk factors.
Published on November 11, 2026
