Study Links Popular Weight Loss Drug to Risk of Rare Blinding Condition

People prescribed the diabetes/weight loss drug semaglutide (also known as Ozempic or Wegovy) have an increased risk of a potentially blinding eye condition, according to a new study from Mass Eye and Ear researchers.

The study was published in JAMA Opthalmology.

Anecdotal experience of NAION

Semaglutide, a drug used for both type 2 diabetes and for overweight and obesity, is becoming a hugely popular drug. It works by mimicking a molecule called glucagon-like peptide 1 (GLP-1) to regulate blood sugar levels and appetite.

This success is despite the drug’s reported side effects, including nausea and vomiting, as well as possible links to gastrointestinal problems.

Dr. Joseph Rizzo, director of the Neuro-Ophthalmology Service at Mass Eye and Ear, noticed some of his group’s patients who developed a blinding eye condition called NAION, or non-arteritic anterior ischemic optic neuropathy, were also taking semaglutide.

“My group saw three patients within a week or two who had NAION and who also were on semaglutide,” Rizzo told Technology Networks.

Sometimes referred to as an “eye stroke”, NAION is a relatively rare condition that affects up to 10 out of 100,000 people in the general population. It is thought to be caused by reduced blood flow to the optic nerve; there are no available treatments.

“Our discussions raised our awareness and curiosity, which led me to think about how we could put together a study,” said Rizzo. “Over the next few weeks as we were laying our plans, additional patients appeared.”

Increased risks

Rizzo and colleagues carried out a retrospective study to investigate whether there is indeed an association between semaglutide and NAION risk.

They analyzed the records of over 17,000 patients treated at Mass Eye and Ear since the release of Ozempic, splitting the patients into two groups depending on whether they had been prescribed semaglutide or other weight loss/diabetes drugs. They also divided the patients into those diagnosed with diabetes or overweight/obesity.

This revealed that semaglutide-prescribed patients had a higher risk of NAION compared with patients prescribed non-GLP-1 agonist medications for diabetes or obesity.

More specifically, those with type 2 diabetes who were prescribed semaglutide were over four times more likely to develop NAION, while those who were overweight or obese were over seven times more likely to be diagnosed.

“A remarkable feature of this class of drugs has been how much benefit they have provided without apparently creating significant and permanent impairments, especially of the nervous system,” said Rizzo.

Further research required

The researchers are now planning further studies to delve deeper into this association, as their JAMA paper cannot prove causality or explain why there were differences in risks between the diabetic and overweight groups. Neither could the study determine if patients actually took their medication as prescribed, a factor which may influence NAION risks.

“We have been exploring our next steps, both in terms of clinical research and laboratory research to try to understand the basis of this effect on the optic nerve,” said Rizzo.

"Our findings should be viewed as being 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. “This is information we did not have before and it should be included in discussions between patients and their doctors, especially if patients have other known optic nerve problems like glaucoma or if there is preexisting significant visual loss from other causes."

Reference: Hathaway JT, Shah MP, Hathaway DB, et al. Risk of nonarteritic anterior ischemic optic neuropathy in patients prescribed semaglutide. JAMA Ophthalmol. 2024. doi: 10.1001/jamaophthalmol.2024.2296

Dr. Joseph Rizzo was speaking to Dr. Sarah Whelan, Science Writer for Technology Networks.

About the interviewee:

Dr. Joseph Rizzo obtained his MD from Louisiana State University and has served as a full-time faculty member in Harvard Opthalmology since 1986. His research focuses on the mechanisms of vision loss, improving diagnosis and the development of new treatments for blinding diseases.