Researchers Find Small Increased Risk of Sudden Vision Loss Associated With GLP-1 Medications

While the risk is low, Rutgers researchers say patients should be aware of this potential association

A medication commonly used to treat Type 2 diabetes and obesity was associated with a slight increase in risk for a rare condition involving reduced blood flow to the optic nerve that can cause sudden vision loss, according to Rutgers researchers.

Their study, published in Annals of Internal Medicine, examined data from a large database of United States adults ages 18 to 65 with Type 2 diabetes who started taking medication to treat the condition, including glucagon-like peptide-1 receptor agonists, or GLP-1s.

GLP-1s, such as semaglutide (sold as Ozempic and Wegovy) and tirzepatide (sold as Mounjaro and Zepbound), are commonly used to treat Type 2 diabetes and obesity and can reduce cardiovascular and kidney disease risks, but researchers still are exploring potential risks of these medications.

Researchers said while the risk is low, the rising use of GLP-1s in patients with and without Type 2 diabetes warrants special attention to medication safety.

Researchers found an association between the use of GLP-1s and a higher risk for the condition, called ischemic optic neuropathy, although the risk remained low.

"Although ischemic optic neuropathy was rare, it is clinically important because it can involve sudden vision loss," said Chintan Dave, a core faculty member of the Center for Pharmacoepidemiology and Treatment Science at Rutgers Institute for Health, Health Care Policy and Aging Research. "The increase in risk was small - approximately three to four additional cases per 10,000 patients treated with GLP-1s over 18 months, but clinicians and patients should be aware of this potential association."

Researchers said while the risk is low, the rising use of GLP-1s in patients with and without Type 2 diabetes warrants special attention to medication safety.

"Most patients in our study who had ischemic optic neuropathy were either men or men and women aged 50 to 65," said Dave, an associate professor at the Ernest Mario School of Pharmacy and the lead author of the study. "Because ischemic optic neuropathy can present with sudden vision loss, which may be permanent, early recognition of symptoms and prompt ophthalmologic evaluation may be especially important for patients at higher baseline risk."

More than four in five cases of ischemic optic neuropathy are estimated to be the non-arteritic anterior form. This type of vision loss is usually permanent, although approximately one-third of patients may experience some improvement, generally within the first six months, Dave said. Even when vision improves, some deficit often remains. The condition typically causes blurring, dimming or loss of part of the visual field in one eye rather than complete blindness or total darkness.

Researchers said the findings may reflect differences in patients' underlying health, rather than a direct effect of the medications. They added that more research is needed to determine causation.

Coauthors of the study include Kamika Reynolds and Kimberly O'Malley of the Institute for Health and Jason Roy of the Rutgers School of Public Health.

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