A major new study has identified a striking connection between Wegovy, the blockbuster weight loss injection, and a rare eye condition that strikes without warning and can rob patients of their sight.
Researchers analyzing millions of adverse event reports submitted to the FDA found that Wegovy carries the strongest statistical link to ischemic optic neuropathy, or ION, a condition where blood flow to the optic nerve gets cut off or severely reduced. The result can be sudden partial or total blindness in one or both eyes.
The signal for Wegovy was nearly five times more powerful than the signal for Ozempic, the diabetes version of the same active ingredient. Published in the British Journal of Ophthalmology, the analysis raises urgent questions about the safety profile of a drug class that millions of people now rely on.
Scientists reviewed over 30.6 million adverse event reports in the FDA database between December 2017 and December 2024, focusing on cases involving semaglutide drugs like Ozempic and Wegovy, as well as tirzepatide medications including Mounjaro and Zepbound. The typical patient was 56 years old, and 54 percent were women.
The raw numbers seem modest at first: researchers found 28 ION reports tied to Wegovy and 47 linked to Ozempic. But the statistical weight told a different story. Wegovy showed odds of ION occurrence that were 75 times higher than expected. Ozempic's odds hit 19 times higher than expected. The oral semaglutide tablet Rybelsus produced no ION reports.
The gender breakdown revealed another critical pattern. Men taking Wegovy faced the highest risk signal of all, with odds 116 times higher than expected. Women showed their strongest signal with Ozempic. Overall, men faced more than three times the risk of ION compared with women.
Researchers believe Wegovy's formulation and dosing may explain the heightened risk. The injectable drug works faster than oral versions and is prescribed at higher doses than Ozempic. The team suggested that Wegovy's aggressive dosing could trigger drops in blood pressure, fluid loss, and disruptions to the autonomic nervous system, all of which might starve the optic nerve of blood supply. The slower absorption and lower doses of Rybelsus may insulate it from the same danger.
The researchers cautioned that no proven cause-and-effect relationship has been established and that heightened media coverage of Wegovy could have prompted more side effect reporting to the FDA.
The FDA's adverse event system has real limitations. It cannot measure how often ION actually occurs in the broader population taking these drugs, and it lacks detailed patient health records or severity assessments. Yet the researchers concluded the findings point to a genuine dose-dependent and formulation-specific safety issue deserving urgent clinical investigation.
"This study provides the first evidence of a formulation-and dose-dependent ION risk, with the strongest association observed for Wegovy," they wrote. "These findings highlight a potential dose-dependent safety concern that warrants urgent prospective evaluation."
Authors of an accompanying commentary echoed the alarm, calling for eye specialists and researchers to scrutinize these drugs more closely. "These findings add to an emerging body of literature reporting ocular complications with anti-obesity medications which warrants further scrutiny and urgent clarification," they noted.
The timing of this warning comes as GLP-1 medications explode in popularity. In the United Kingdom alone, 29 percent of adults are obese and 64 percent are overweight or obese. Beyond weight loss and diabetes treatment, researchers are investigating these drugs for cardiovascular benefits, stroke prevention, and dementia risk reduction. Prescriptions are expected to climb further.
The expanding use raises particular concerns about children and teenagers. Regulators are debating whether anti-obesity drugs should be approved for children over 12, a shift that could expose a much larger population to rare complications like ION decades down the road.
The picture remains mixed. Some research suggests GLP-1 drugs may actually help certain eye conditions, including age-related macular degeneration and uveitis. But that potential upside must now be weighed against the risk of sudden vision loss.
Author Jessica Williams: "A five-fold safety signal shouldn't be ignored just because the condition is rare, especially when we're talking about a drug being prescribed to millions of people for cosmetic weight loss."
Comments