The popular weight-loss drug Wegovy may carry a small risk of "eye stroke," a sudden and potentially devastating form of vision loss, according to a study published in March in the British Journal of Ophthalmology. But researchers and outside experts are urging users not to panic. The rate of the condition is extremely low, and most specialists say the risks do not outweigh the drug's benefits.
The condition in question is ischemic optic neuropathy, or ION, which occurs when blood flow to the optic nerve is interrupted. It can cause rapid, painless vision loss in one or both eyes. In the study, ION appeared in less than 1% of patients who reported experiencing side effects while taking Wegovy.
"This is a very sudden and painless way to lose your eyesight," said Barbara Pierscionek, deputy dean of research and innovation at Anglia Ruskin University. "You can lose vision in one of your eyes or both of them. We're not quite sure exactly how it happens, but it is essentially a blockage of the blood vessels in the eye."
The study focused specifically on Wegovy, one of the most widely used drugs for chronic weight management. Its active ingredient is semaglutide, the same compound found in the diabetes drug Ozempic. To investigate whether certain weight-loss drugs presented a higher ION risk than others, the research team examined side effect reports submitted to the U.S. Food and Drug Administration from December 2017 onward.
This is not the first time semaglutide has been connected to eye health concerns. A 2025 review of clinical trials and observational studies found a slightly elevated risk of eye stroke in diabetes patients using the drug, though that risk was not seen in patients taking it specifically for weight loss. The new study goes further, zeroing in on Wegovy's profile among weight-management medications as a class.
Dr. Amanda Adler, a professor of diabetic medicine and health policy at the University of Oxford who was not involved in the research, told Live Science that the risks "do not outweigh the benefits of semaglutide." She noted that the U.K.'s Medicines and Healthcare products Regulatory Agency is now advising semaglutide users to seek urgent medical attention if their eyesight deteriorates quickly.
The findings add to a growing body of evidence that scientists and regulators are watching closely. For now, the link between Wegovy and ION is considered a signal, not a confirmed causal relationship. Researchers say further investigation is needed to understand whether the drug directly causes the condition or whether other factors in patients' health profiles play a role.
