- New study finds association between semaglutide and rare eye disease.
- This condition, called nonarteritic anterior ischemic optic neuropathy, can lead to blindness.
- The authors stress that these results are preliminary and that further research is needed.
A new study, published in
The disease, called non-arteritic anterior ischemic optic neuropathy (NAION), affects about
The new study found that people with diabetes who were prescribed semaglutide (marketed as Ozempic and Wegovy, among others) were more than four times more likely to develop NAION than people with diabetes taking other medications.
Similarly, people who were prescribed the drug to treat overweight or obesity were seven times more likely to be diagnosed with NAION than people taking other weight-loss drugs.
Although relatively rare, NAION is a leading cause of blindness in the United States. It causes permanent, painless vision loss that
Today’s Medical News I spoke with Joel Kopelman, MD, a board-certified oculofacial plastic surgeon and ophthalmologist.
He explained: “This vision loss can be mild or severe. The disease can progress rapidly, with vision loss usually occurring within days or weeks of the onset of symptoms.”
Kopleman, who was not involved in the recent study, also told us that NAION has “an estimated incidence of 2 to 10 per 100,000 persons per year in the United States. The prevalence is similar globally,” he explained, “although exact numbers may vary based on regional demographics and reporting practices.”
Most often, this disease affects middle-aged or elderly people of white race. It usually affects only one eye at a time. However, in about 43% of people, the other eye is affected within 3 years.
MNT contacted Dr. Arun Gulani, an ophthalmic surgeon at the Gulani Vision Institute, who explained that there is “no established treatment protocol for NAION, which is considered irreversible.”
However, Gulani, who was also not involved in the study, told us that “experimental treatments are being evaluated nationally and globally.”
The lead author of the recent study is Dr. Joseph Rizzo, director of neuro-ophthalmology at Mass Eye and Ear in Boston, Massachusetts. He initially decided to study the link between semaglutide and NAION based on an observation.
He and his colleagues found that three patients in their practice were diagnosed with NAION in just one week. That’s an unusual finding for such a rare disease. Rizzo and his colleagues also found that all three patients were taking semaglutide.
To conduct their study, they analyzed retrospective data from 16,827 patients from the Mass Eye and Ear. They divided the individuals into two groups based on the reason for taking the drug: type 2 diabetes or obesity.
In both groups, some received semaglutide, while others took unrelated drugs to treat their disease. This distinction is important because people with diabetes are at increased risk of NAION, so analyzing them separately could account for this.
In the diabetes group, 8.9% of people taking semaglutide were diagnosed with NAION, compared with 1.8% of people taking other diabetes medications.
Similarly, in the obese group, 6.7% of people taking semaglutide developed NAION, compared with only 0.8% of people taking other drugs.
This means that people with diabetes taking semaglutide were four times more likely to be diagnosed with NOIAN. People taking semaglutide to treat obesity were seven times more likely to be diagnosed.
“Although the exact mechanism linking semaglutide to NAION is not fully understood,” Kopelman said MNT“There are a few theories.”
He explained that semaglutide “may influence vascular health and blood flow, potentially contributing to ischemic events in predisposed individuals.”
An ischemic event occurs when an organ or tissue does not receive enough blood, and therefore oxygen. NAION is caused by ischemia specifically at the optic nerve level.
“Patients with diabetes are already at higher risk for vascular complications,” he continued, “and any additional factors that could affect blood flow to the optic nerve could increase the risk of NAION.”
Another theory concerns the mechanism of action of semaglutide. Semaglutide is a GLP-1 agonist, which means that it acts on a receptor called GLP-1.
The study authors note that GLP-1 receptors are present on the optic nerve. Their activation may influence the blood supply to the optic nerve, thereby increasing the risk of NAION.
Scientists will need to do much more work to explore the links between semaglutide and NAION. Then, if confirmed, further work will be needed to elucidate the mechanisms involved.
We asked Kopelman if there are ways to reduce the risk of developing NAION. “To reduce the risk of NAION, you need to manage the underlying health conditions that contribute to its development,” he explained.
He highlighted the following key preventive measures:
- control blood pressure and diabetes — it is essential to maintain optimal control of blood pressure and blood sugar
- regular eye exams — regular checkups with an eye doctor can help monitor and manage risk factors
- healthy lifestyle —adopting a healthy lifestyle, including a balanced diet, regular physical activity and avoiding smoking, can improve overall vascular health.
The study does have limitations, however. As the authors explain, because their institution specializes in eye diseases, they are more likely to see a higher number of cases of NOIAN. This means that their findings “may not be fully generalizable to other settings.”
They also note that their records only show whether a patient was dispensed a drug, not whether they took it as prescribed. Finally, because NAION is rare, their analysis only looks at a small number of cases. That can make the statistics harder to interpret.
However, given the caveats, the authors write: “If true, our data anticipate an increasing number of NAION cases associated with this class of drugs.”
They believe their research is the first to link NAION risk to semaglutide.
“Our results should be considered significant but tentative, as future studies are needed to examine these questions in a much larger and more diverse population,” Rizzo said in a press release.
He indicated that:
“This is information we didn’t have before and it should be included in discussions between patients and their doctors, particularly if patients have other known optic nerve problems such as glaucoma or if there is significant pre-existing visual loss due to other causes.”