Ozempic Users Face Double Risk of Rare Vision Loss, Nordic Studies Find

Despite the findings, researchers cautioned against the immediate cessation of Ozempic treatment.

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Danish researchers are raising concerns about the widely prescribed diabetes drug Ozempic after discovering that it significantly increases patients’ risk of experiencing what doctors describe as a “stroke of the optic nerve.”

Ozempic Found to Double the Risk

The study findings, published in the International Journal of Retina and Vitreous, suggest that the use of Ozempic (semaglutide) more than doubles the risk of developing non-arteritic anterior ischemic optic neuropathy (NAION), a serious eye condition characterized by sudden vision loss in one eye, because of inadequate blood flow to the optic nerve. NAION is considered the most common cause of sudden vision loss in people older than 50.

“You can reasonably consider it as a stroke of the optic nerve,” Dr. Joseph Rizzo III, professor of ophthalmology and director of the neuro-ophthalmology service at Harvard Medical School’s Massachusetts Eye and Ear, told The Epoch Times. “And, like a stroke, you lose function.”

Symptoms of NAION include:

• Sudden Vision Loss: Usually occurs upon waking up in the morning or after a nap.
• Painless Vision Loss: Unlike other eye conditions, NAION is typically painless.
• Vision Loss in One Eye: Typically affects only one eye, although it can sometimes affect both eyes.
• Blurred Vision: Vision may be blurry or distorted, especially in the lower half of the visual field.
• Loss of Color Vision: Some people may experience a loss of color perception or see colors differently.
• Shadow in the Visual Field: Some patients may see a dark shadow or blind spot in their field of vision.

Researchers examined data from 424,152 Danish patients diagnosed with Type 2 diabetes to investigate the link between Ozempic and increased NAION risk. The findings indicated that Ozempic significantly heightens the risk of developing the debilitating condition.​

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“We found that Ozempic more than doubles the risk of developing NAION,” Jakob Grauslund, professor of ophthalmology at the University of Southern Denmark’s Department of Clinical Research, said in a statement. “It is a condition that can lead to severe and permanent loss of vision.”

Rise in NAION Cases Since Ozempic Introduction

There has been a marked increase in NAION cases since Ozempic was introduced in Denmark in 2018, according to Grauslund.

“Whereas we used to see between 60 and 70 cases of NAION per year, we are now seeing up to 150,” he said, pointing out that the majority of hospital admissions for NAION are now among patients with Type 2 diabetes.

Similarly, in a related preprint study not yet peer-reviewed, Anton Pottegard, professor of pharmaceuticals at the Department of Public Health at the University of Southern Denmark (SDU), and his team examined new Ozempic users among Type 2 diabetes patients in Denmark and Norway. Consistent with Grauslund’s findings, Pottegard’s team reported that the risk of developing NAION doubles with Ozempic use.

While the current studies revealed a lower number of cases compared with a previous U.S. study—which found that the risk more than doubled—both Danish studies corroborate a similar risk for diabetes patients using Ozempic.

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In an emailed statement, Pottegard told The Epoch Times that these studies will likely trigger “quite a few” new regulatory and research actions.

“The regulators have now initiated a process of evaluating the studies to decide whether NAION should be acknowledged formally as a side effect to Ozempic,” he wrote. “We do not (yet) know whether this is a class effect, i.e. also affects use of tirzepatide and the other new drugs incoming, or [is] specific to semaglutide.”

According to Pottegard, the findings from the new study will “no doubt be the subject of new research,” and in the event that the regulators acknowledge the risk, they could establish monitoring programs for the other drugs in this class.

“And then there’s certainly a need for research into not only why this happens (we have no idea about the mechanism) but also what patients are at risk of experiencing it,” he wrote.

Findings Don’t Mean Stopping Ozempic Use

Despite these findings, the Danish researchers cautioned against the immediate cessation of Ozempic treatment.

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“This is a serious but very rare side effect. Often, we only learn about this kind of thing after a new drug has been on the market for a few years,” Pottegard clarified in the statement. “It should be emphasised that it is neither more serious nor more common than the rare side effects of many other medicines that we continue to use.”

Additionally, Kurt Hojlund, diabetes professor at SDU’s Steno Diabetes Center Odense, stressed in the statement the importance of treating Type 2 diabetes while taking into account the associated risks of Ozempic.

“It is extremely important that Type 2 diabetes is treated, but you have to consider whether the small increased risk of severe vision loss by using Ozempic means that you should instead use one of the other new drugs that protect against kidney and cardiovascular disease,” he said.

Novo Nordisk Responds

In a statement emailed to The Epoch Times, Novo Nordisk said NAION is a very rare eye disease but that it is not an adverse drug reaction for the marketed formulations of semaglutide (Ozempic, Rybelsus, and Wegovy) per the approved labels.

“After a thorough evaluation of the studies from SDU and Novo Nordisk’s internal safety assessment, Novo Nordisk is of the opinion that the benefit-risk profile of semaglutide remains unchanged,” a spokesperson for the company wrote.

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The Novo Nordisk spokesperson stated that while both studies showed roughly a doubling of relative risk, the absolute risk and absolute number of people affected is very low.

“This aligns with the very low annual incidence of this rare disorder. One of the studies found that 2 people per 10,000 patients treated with semaglutide in a year developed NAION versus 1 out of every 10,000 in the comparator group, concluding that the absolute risk is very low,” the Novo Nordisk spokesperson wrote, adding that the studies did not demonstrate a causal relationship between semaglutide and NAION.

“Novo Nordisk, on its part, has conducted an analysis across randomized controlled clinical trials with GLP-1 receptor agonists, including a blinded ophthalmologist evaluation to confirm NAION diagnoses. Through this analysis, very few cases of ophthalmologist-confirmed NAION cases were identified, with no imbalance disfavoring Novo Nordisk GLP-1 receptor agonists.”