NBC News
People who use Ozempic and Wegovy may be at increased risk of developing an eye condition that can weaken vision or cause irreversible vision loss, according to a study published Wednesday in the journal JAMA Ophthalmology. However, the authors stress that more research is needed to confirm the link between these drugs and vision problems.
Non-arteritic anterior ischemic optic neuropathy, or NAION, is a condition that affects the optic nerve, a bundle of fibers connected to the back of the eye that transmits signals to the brain so a person can see. When people have NAION, blood flow to the optic nerve is reduced or blocked, resulting in sudden vision loss.
“This is actually a stroke of the optic nerve,” said Dr. Joseph Rizzo, senior author of the study and director of neuro-ophthalmology at Mass Eye and Ear Hospital in Boston.
NAION is the second most common optic nerve disease in the United States, with an incidence of up to 10 per 100,000 people, and one of the most common causes of sudden blindness, according to the American Academy of Ophthalmology.
It is a chronic disease with no known treatment.
The new study is based on an analysis of medical records from more than 16,800 Boston-area patients spanning six years, none of whom were initially diagnosed with NAION.
Researchers focused on a subset of those patients — about 1,700 — who were diabetes, overweight or obese, and compared outcomes after 36 months in those who received semaglutide versus those who did not. Semaglutide is the ingredient in Ozempic and Wegovy.
Nearly 200 diabetic patients were prescribed semaglutide and 17 developed NAION, a rate four times higher than those who did not receive the drug. In the obesity group, 361 people were prescribed semaglutide and 20 developed the disease, a rate seven times higher.
Rizzo noted that because the results are based on a review of existing data, researchers cannot say for sure that semaglutide causes the eye condition. She added that a large randomized controlled trial is still needed to confirm a link.
“What it does show is that there is a relationship between the use of semaglutide and the development of this disorder, in which vision is lost,” he said.
Dr. Andrew Lee, a spokesman for the American Academy of Ophthalmology and a neuro-ophthalmologist at Houston Methodist Hospital, said he has had some patients on semaglutide who developed NAION, but the question has always been whether “it’s a causal relationship or just an association.”
Limitations of the study
People with type 2 diabetes are already at increased risk for vision problems, including NAION. Another vision problem, diabetic retinopathy, is the leading cause of blindness in adults and is caused by damage to the retina due to high blood sugar levels.
Additionally, risk factors for NAION include sleep apnea and hypertension, which are more likely to occur in people with obesity.
Lee said it’s plausible that weight-loss drugs could cause the disease, but it’s “premature to conclude” a link based on the single study. “The study can only generate a hypothesis” of a possible link, he said.
Some anecdotal reports have suggested that weight loss drugs may be linked to vision problems, such as blurred or distorted vision.
Rizzo said it’s not clear how weight-loss drugs might cause this condition. It could be due to some mechanism in the class of drugs called GLP-1 in general, he said, or something specific in the way semaglutide works. The study looked only at semaglutide, not at other popular weight-loss drugs, such as tirzepatide, the active ingredient in Mounjaro, and Zepbound, from drugmaker Eli Lilly.
Consult a doctor
Rizzo said patients should talk to their doctor if they are concerned about developing a potential health condition.
“As someone who sees patients with diseases like this, if a person is already suffering from vision loss for whatever reason and was wondering if they could take semaglutide, I would just urge caution,” Rizzo said.
Dr. Shauna Levy, an obesity specialist and medical director of the Tulane Bariatric Center in New Orleans, said the findings won’t change the way she prescribes the drugs.
“For now, the risk still appears low,” he said.
In a statement, a Novo Nordisk spokesman said the study was not sufficient to establish a link between semaglutide and the eye condition.
“Patient safety is a top priority for Novo Nordisk, and we take all reports of adverse events resulting from the use of our medicines very seriously,” the spokesperson said.
