Wegovy Linked to Fivefold Risk of Permanent Sight Loss, Study Reveals

A groundbreaking study has revealed a potential link between Wegovy, a popular weight loss injection, and an increased risk of permanent sight loss, with users facing a fivefold higher likelihood of experiencing a condition known as ischemic optic neuropathy (ION) compared to those on other GLP-1 medications. The findings, published in the *British Journal of Ophthalmology*, have sparked urgent concerns among medical professionals and regulators, raising questions about the safety of semaglutide—the key ingredient in Wegovy, Ozempic, and Rybelsus. This drug, hailed as a medical breakthrough in the fight against obesity, now stands at the center of a growing controversy over its potential to cause irreversible vision damage.

The study, conducted by Canadian researchers, analyzed adverse event reports submitted to the US Food and Drug Administration (FDA) between December 2017 and 2024. It found that Wegovy, manufactured by Novo Nordisk, carried the highest risk of ION, with men facing a threefold greater chance than women. ION, often referred to as an 'eye stroke,' occurs when blood flow to the optic nerve is blocked, leading to sudden and typically permanent vision loss. Despite previous manufacturer claims that blindness was not a known side effect, the study provides the first evidence of a dose-and-formulation-dependent risk.

Semaglutide, the active ingredient in all three drugs, was found to be associated with the highest number of ION reports, particularly at higher doses. Wegovy, which contains 2.4mg of semaglutide, was linked to 75 times more ION reports than Ozempic, which has a lower dose (2mg). Rybelsus, the oral form of semaglutide, showed no such connection. Researchers speculated that the higher dose of Wegovy might lower blood pressure, reducing blood flow to the optic nerve, while Rybelsus's slower absorption minimizes this risk.

The implications of these findings are significant, especially as the use of weight loss medications expands. The UK's Medicines and Healthcare products Regulatory Agency (MHRA) recently issued a warning, urging patients to report sudden vision changes to medical professionals. Since semaglutide's approval in the UK in 2018, three suspected cases of ION have been reported. However, usage has surged dramatically, with an estimated 1.6 million people in Britain using Wegovy or Mounjaro in the past year alone. The majority of these users access the drugs privately, with prescriptions doubling between 2024 and 2025.

Public health experts have raised alarms about the long-term risks, particularly for children, who may face heightened vision problems as these drugs become more common. The study's authors emphasized the need for further research and immediate regulatory action, calling for urgent evaluations to guide prescribing practices. Currently, there are no treatments for ION, and vision loss is typically permanent.

Novo Nordisk, the manufacturer of semaglutide, has faced multiple lawsuits in the US, with patients alleging that the drug caused blindness. In response, the company stated that its priority remains patient safety and that it continues to collaborate with global regulators to monitor drug safety. It maintains that the current evidence does not confirm a causal link between semaglutide and ION, citing a favorable benefit-risk profile. Nevertheless, safety warnings have been added to drug labels in the EU, reflecting the growing concern.

As the debate intensifies, the medical community is left grappling with a complex balance: the life-changing benefits of semaglutide in treating obesity and type 2 diabetes against the emerging risks to vision health. With millions relying on these drugs, the urgency for clearer guidelines, further studies, and proactive patient monitoring has never been higher. The question remains: how can the medical field ensure the safe and responsible use of a medication that, while transformative, may carry unforeseen consequences for some?