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Research has shown that people with diabetes or obesity who take Ozempic or Wegovy may be at higher risk of a rare disease that can cause blindness.
CNN
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A new study suggests that people taking Ozempic or Wegovy may be at higher risk for a rare form of blindness, but doctors say that shouldn’t discourage people from using the drugs to treat diabetes and obesity.
Last summer, doctors at Massachusetts Eye and Ear Infirmary noticed an unusually high number of patients with nonarteritic anterior ischemic optic neuropathy (NAION), a type of eye stroke that causes sudden, painless loss of vision in one eye.
The condition is relatively rare – around 10 in 100,000 people in the general population may experience it – but doctors noticed three cases in one week, and each of the patients was taking the drug semaglutide.
Looking back at six years of medical records, the researchers found that people with diabetes taking the prescription drug semaglutide were more than four times more likely to be diagnosed with NAION, and overweight or obese people taking the drug were more than seven times more likely to develop the condition. The risk was found to be highest within the year of receiving a semaglutide prescription.
of studyThe study, published Wednesday in the medical journal JAMA Ophthalmology, cannot prove that the drug semaglutide causes NAION, and the small number of cases identified at one specialized medical center — an average of about 100 cases each year — may not apply to the broader population.
Novo Nordisk, the only US manufacturer of semaglutide, stressed that the data from the new study are insufficient to prove a causal relationship between semaglutide use and NAION.
“Patient safety is a top priority for Novo Nordisk and we take all reports of adverse events with the use of our medicines very seriously,” a company spokesperson said in an email to CNN.
Prescriptions of semaglutide have risen sharply in the United States, potentially putting an increasing number of people at risk for potential side effects, and NAION is the second leading cause of optic nerve blindness after glaucoma.
But even with the increased risk, the condition remains relatively rare.
“The use of these medications has exploded throughout the developed world and has provided enormous benefits in many ways, but future discussions between patients and their physicians must consider NAION as a potential risk,” lead researcher Dr. Joseph Rizzo, chief of neuro-ophthalmology at Massachusetts Eye and Otolaryngology and professor at Harvard Medical School, said in a news release. “Our findings, while important, should be considered preliminary. Future studies should explore these questions in larger, more diverse populations.”
Experts agree that the potential risk of NAION should not preclude the use of semaglutide medication in treating diabetes and obesity.
“The systemic therapy landscape is constantly changing, and remaining vigilant for potential new disease associations is a duty we all share for our patients,” ophthalmologist Susan Moran of University Hospitals Birmingham, UK, said in a related article. But the large number of people taking semaglutide should give us confidence that the absolute risk of developing NAION as a result is rare.
It is not fully understood how semaglutide affects the eyes, nor is the exact cause of NAION. The condition causes damage to the optic nerve, but there are often no signs before vision loss.
Changes in blood sugar can affect the shape of the eye’s lens, which can affect vision, said Dr. Disha Narang, an endocrinologist and director of obesity medicine at Endeavor Health in Chicago, who was not involved in the study.
And the use of semaglutide, which stimulates the body to secrete insulin to lower blood sugar levels, Previously linked Temporary vision changes (new or worsening diabetic retinopathy, or damage to the blood vessels at the back of the eye) are likely related to the sudden improvement in blood sugar levels. The Ozempic and Wegovy product labels list vision changes as a potential side effect, and Novo Nordisk is investigating the association between semaglutide use and diabetic retinopathy in a clinical trial due to be completed in 2027.
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While there is a “biologically plausible mechanism” for the potential interaction, “association is not causation, and diabetes is a known risk factor for NAION,” Dr. Andrew Lee, a clinical spokesman for the American Academy of Ophthalmology and a neuro-ophthalmologist at Houston Methodist Hospital who was not involved in the study, told CNN in an email.
For now, experts say patients taking semaglutide or considering the treatment should discuss the risks and benefits with their doctors, especially if they have other known optic nerve diseases such as glaucoma or existing vision loss.
“It’s important that patients consult with their ophthalmologist if they experience changes in their vision,” Narang said. “It’s important that patients speak to a doctor who is comfortable prescribing semaglutide, discuss what is and is not clinically important, and discuss the benefits and risks of long-term treatment.”