A Canadian study has found that the weight loss drug Wegovy has a rate of ischemic optic neuropathy (ION) almost five times higher than Ozempic.
The semaglutide drugs are widely used to help with weight loss and manage diabetes. However, reports of eyesight problems related to their use have prompted reviews of their risk.
In a study published in The British Journal of Ophthalmology,1 a team from universities across Canada analysed records of adverse events collected by the US Food and Drug Administration over seven years, from 2017 to 2024, and looked for cases of ION.
The rare condition can cause sudden and complete vision loss due to a lack of blood flow to the optic nerve.
The researchers looked at cases of ION occurring in people taking different semaglutide formulations: Wegovy (for weight loss), Ozempic (for type 2 diabetes), and the oral drug Rybelsus (for type 2 diabetes).
The statistical analysis deployed by the team found that the odds of a Wegovy-related ION complaint were almost five times higher than with Ozempic, while no clear relationship was found between Rybelsus and ION.
The analysed database included more than 30 million so-called adverse events.
“Ozempic generated about seven times more reports than Wegovy owing to its earlier approval in 2017 versus Wegovy’s 2021 launch. Despite this difference in volume, Wegovy showed the strongest ION signal (n=28, ROR=74.89, 95% CI 51.79 to 108.29), exceeding Ozempic (n=47, ROR=18.81, 95% CI 14.11 to 25.07) and any form of semaglutide (n=85, ROR=21.37, 95% CI 17.40 to 26.65).”
When adjusted for age and demographic factors, including sex, the odds of ION among Wegovy users were 4.74 times higher than with Ozempic, based on reported cases.
Men taking semaglutide of any kind were about three times more likely to report a case of ION than women.
“These findings highlight a potential dose-dependent safety concern that warrants urgent prospective evaluation to guide prescribing and regulatory policy,” the researchers wrote.
Reference
Lakhani M, Al-Ani A, Margolin E, et al. Ischemic optic neuropathy with semaglutide: global observational analysis of sex- and formulation-specific risk. Br J Ophthalmol. 2026 Mar 10: bjo-2025-328483. doi: 10.1136/bjo-2025-328483. Epub ahead of print.
