Eye Doctors Are Finding New Links Between Ozempic and Vision Problems

The case for GLP-1 drugs like Ozempic possibly causing blindness is building. A new paper out this week describes several people who developed eye conditions soon after they began taking semaglutide and similar medications.

Eye doctors at the University of Utah Health and elsewhere published the research, which describes several cases of vision complications possibly tied to these obesity and diabetes drugs. The medications were linked to three different eye conditions, all of which can lead to blindness. But as the doctors caution, the cases alone do not prove that GLP-1 drugs can cause these issues, and more research is needed to understand exactly what’s going on.

Other research has recently suggested a connection between GLP-1 drugs like semaglutide (the active ingredient in Ozempic and Wegovy) and tirzepatide (Mounjaro and Zepbound) and a higher risk of certain eye problems.

Last summer, for instance, researchers at a specialty eye hospital published a study finding that patients prescribed semaglutide were noticeably more likely to develop nonarteritic anterior ischemic optic neuropathy (NAION), a rare condition caused by a loss of blood flow to the optic nerve. This past December, health officials in Denmark called for the European Union to formally investigate the potential link between GLP-1 use and NAION, following two other studies of Danish residents that found similar results.

This latest paper, published last month in JAMA Ophthalmology, presents a series of nine cases. Seven of the cases include people who experienced NAION after starting a GLP-1 drug; one person developed papillitis, a type of inflammation of the optic nerve; and another developed paracentral acute middle maculopathy, a type of blood vessel damage in the macula, the central area of the retina that allows for sharp vision. In many cases, people’s vision loss resolved or stopped worsening after they stopped using the medication, though a few maintained their therapy with no lasting issues.

The researchers are quick to note these individual cases aren’t a smoking gun for proving that GLP-1 drugs are causing these eye problems.

“In this case series study, it was not possible to determine if there is a causal link between these drugs and the ophthalmic complications reported,” they wrote. And if such a causal link does exist, it may also be more complicated than it appears at first glance.

All but one person involved someone with a history of type 2 diabetes, a condition characterized by consistently elevated high blood sugar. The researchers note that some cases of papillitis have been tied to a rapid drop in people’s blood sugar, and they speculate the same could be true for some cases of NAION. In other words, GLP-1 drugs might be causing at least some of these cases indirectly, by rapidly lowering blood sugar, rather than through any direct toxic effect of the medication itself. But there may be other triggers to consider. Some cells in the optic nerve carry GLP-1 receptors, for instance, providing another way for these drugs to harm eye function.

Either way, the researchers say that more work is needed to study this potential link. Though NAION is rare, even a small increase in risk of it could still affect many people, given how popular these drugs are becoming worldwide. And unraveling the mechanisms behind this connection could lead to better care. If these conditions are caused by a rapid drop in blood glucose, as the researchers believe, then we could prevent future cases by simply recommending a slower course of GLP-1 treatment in high-risk patients (GLP-1 therapy is typically given in escalating doses over time). The doctors also hope their findings will promote awareness of the potential link among their colleagues.

“Further studies are needed to test our hypothesis. However, this is an important issue for ophthalmologists as we monitor usage of these drugs and how to best be in communication with our patients about them,” said Bradley Katz, a neuro-ophthalmologist at the University of Utah’s John A. Moran Eye Center, in a statement from the university.