A new study suggests that popular weight loss and diabetes medications, Ozempic and Wegovy, may increase the risk of a rare form of blindness called non-arteritic anterior ischemic optic neuropathy (NAION). However, doctors advise that patients should not be deterred from using these medications for treating diabetes or obesity.
Last summer, doctors at Mass Eye and Ear observed an unusually high number of NAION cases, a type of eye stroke causing sudden, painless vision loss in one eye. The condition, affecting up to 10 out of 100,000 people, saw three new cases in one week, all patients on semaglutide medications.
A review of six years of medical records revealed that diabetics on semaglutide were over four times more likely to be diagnosed with NAION, and those overweight or obese were over seven times more likely. The highest risk was within the first year of taking semaglutide.
Published in JAMA Ophthalmology, the study doesn’t prove causation, and the small sample size from one medical center may not reflect broader populations. Novo Nordisk, the maker of semaglutide medications, emphasized that the data is insufficient to establish a causal link between semaglutide use and NAION.
Despite the increased prescriptions of semaglutide in the U.S., NAION remains uncommon. The condition is the second leading cause of optic nerve blindness after glaucoma. “Future discussions between patients and their physicians should include NAION as a potential risk,” said Dr. Joseph Rizzo, lead researcher and director of neuro-ophthalmology at Mass Eye and Ear.
Experts agree the potential risk should not discourage the use of semaglutide for diabetes or obesity treatment. Ophthalmologist Susan Mollan highlighted the importance of vigilance for new disease associations, noting the rare absolute risk despite widespread semaglutide use.
The mechanisms by which semaglutides affect the eyes are not entirely understood, nor is the exact cause of NAION. Semaglutides, which increase insulin production to lower blood sugar, have been linked to temporary vision changes and diabetic retinopathy. Both Ozempic and Wegovy labels include vision changes as potential side effects, and Novo Nordisk is conducting a trial on this link, expected to complete in 2027.
The FDA continuously reviews data on drug risks, including GLP-1 receptor agonists like semaglutide. For now, patients using or considering semaglutide should discuss risks and benefits with their doctors, especially if they have existing optic nerve issues. “Consult with ophthalmology if experiencing visual changes,” advised endocrinologist Dr. Disha Narang, stressing the importance of informed discussions about long-term therapy benefits and risks.
