A new study suggests patients taking semaglutide — the active ingredient in Ozempic and Wegovy — may be at higher risk of an eye condition that can cause blindness. However, study authors and experts told NBC News the findings only show an association, and that additional research is needed to confirm a causal link.
The study, published July 3 in JAMA Ophthalmology, found patients taking Ozempic and Wegovy were more likely to develop non-arteritic anterior ischemic optic neuropathy, known as NAION, a condition that restricts blood flow to the optic nerve and causes sudden vision loss.
Researchers from Mass General Brigham and Harvard Medical School, both based in Boston, conducted a retrospective study using medical record data from a registry of patients who had no history of NAION and were seen by neuro-ophthalmologists at an academic institution between 2017 and 2023. They focused on a subset of about 1,700 patients who had diabetes, were overweight or had obesity, and compared outcomes after 36 months in those taking semaglutide and those who were not prescribed the drug.
Seventeen of the 200 diabetes patients taking semaglutide went on to develop NAION, a rate that was four times higher than those not taking it. In the obesity group, 20 of 361 patients taking the drug developed the condition, a rate that was seven times higher.
A Novo Nordisk spokesperson told the news outlet the study is not sufficient to establish a link between semaglutide and NAION and shared the following statement:
"Patient safety is a top priority for Novo Nordisk, and we take all reports about adverse events from the use of our medicines very seriously."
Anecdotally, some physicians say they've had patients taking semaglutide who developed the condition, though emphasize it's premature to conclude the blockbuster drugs cause NAION, especially because diabetes and related conditions are risk factors for it. A large, randomized controlled clinical trial is necessary to study a causal link, experts said.