In a large analysis of global adverse event reports linked to glucagon-like peptide-1 receptor agonist (GLP-1) semaglutide, Wegovy users had nearly five times the odds of developing ischaemic optic neuropathy (ION) compared with those using Ozempic.

Researchers from Canada’s University of Toronto and St Michael’s Hospital reviewed more than 30 million FDA reports filed between 2017 and 2024, including 31,774 involving semaglutide, and found the strongest signal with Wegovy. Writing in the British Journal of Ophthalmology, they found a reporting odds ratio of 74.89 for Wegovy compared with 18.81 for Ozempic.

Men were also at greater apparent risk, with around threefold higher odds of developing ION than women. The authors said the findings may point to a formulation- or dose-related effect, with injectable semaglutide showing a stronger signal than oral semaglutide, but stressed the study was observational and based on spontaneous safety reports, so could not establish causation. They said prospective studies are needed to clarify the absolute risk and any implications for prescribing and patient counselling.