Can New Weight Loss Drugs Cause Blindness? New Study Adds to Debate

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Could newer weight loss drugs like semaglutide (Ozempic) and tirzepatide (Zepbound) be putting patients at risk of blindness? The answer is complicated, according to a new study.

A report of nine incidences of progressive vision loss among people using semaglutide or tirzepatide, the study adds to a growing body of work examining the trend, but study investigators point out there was no way to link the use of these new agents directly to ophthalmic conditions reported.

“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. In some cases, we hypothesize that rapid correction of hyperglycemia induced by these drugs, rather than a toxic effect of the drugs, could be associated with the ophthalmic complications reported,” wrote the study team, who was led by Bradley Katz, M.D., Ph.D., a neuro-ophthalmologist at the John A. Moran Eye Center at the University of Utah.

Driven by growing rates of overweight and obesity, the United States has witnessed a significant surge in the popularity of weight loss medications, particularly semaglutide and tirzepatide, in recent years. Originally developed to manage type 2 diabetes, these medications have gained widespread attention for their substantial weight loss benefits during the last decade. Semaglutide, marketed under names like Ozempic and Wegovy, and tirzepatide, known as Zepbound or Mounjaro, have been embraced by both the medical community and the public as effective tools in combating obesity.

A survey conducted by KFF found that about 13% of U.S. adults have tried GLP-1 agonists, the class of drugs to which semaglutide and tirzepatide belong, highlighting their growing prominence in weight management strategies. A study published in the Journal of the American Medical Association found more than half of all U.S. adults qualify for semaglutide based on the criteria of trials used for support of its U.S. Food and Drug Administration approvals.

However, as their popularity has increased so have reports of side effects associated with these agents. While some of these effects may be cosmetic in nature, such as “Ozempic face,” other reports purport a more present danger to patients, including reports of blindness. The report from Katz and colleagues comes less than a year after another report in the Journal of the American Medical Association suggested a link between semaglutide use and nonarteritic anterior ischemic optic neuropathy (NAION), which is a condition that causes sudden vision loss.

After having a patient who developed NAION one day after starting treatment with semaglutide, Katz launched the current study. To learn more, Katz sought insight from other neuro-ophthalmologists through NANOSnet, an electronic mailing list available to North American Neuro-Ophthalmology Society members.

From their search, Katz and team reported on nine individuals. The age range of this group was 37 to 77 years, 56% were female, and all nine experienced an ophthalmic complication in association with the use of semaglutide or tirzepatide.

Among the nine included in the study, seven reported NAION, one reported bilateral papillitis, and one reported paracentral acute middle maculopathy. Across the nine cases, Katz and team identified several atypical features, including sequential ischemic optic neuropathy, bilateral disc swelling at presentation and progressive vision loss.

However, the study team was not able to draw any causal links between the initiation of these therapies and onset of ophthalmic conditions reported but said they could be the effect of rapid hyperglycemia corrections.

“We propose that a possible connection between incretins and NAION could be rapid correction of hyperglycemia, resulting in optic nerve swelling and subsequent infarction,” wrote Katz and team.