In the bustling world of weight-loss drugs, where medications like Ozempic and Wegovy have been hailed as straight-up revolutionary, a darker side is creeping. A small but growing body of research suggests that these drugs, which have transformed the lives of millions struggling with obesity and diabetes, may carry an unexpected risk: vision loss.

The phenomenon, dubbed “Ozempic blindness” by some, has sparked concern among patients and physicians alike. While the evidence is far from conclusive and the potentially affected patients are few and far between, the stories of those affected are impossible to ignore.

A Rare but Alarming Connection

The latest study, published in JAMA Ophthalmology, examined nine patients who developed severe eye conditions while taking semaglutide (the active ingredient in Ozempic and Wegovy) or tirzepatide (found in Mounjaro and Zepbound). Seven of these patients experienced non-arteritic anterior ischemic optic neuropathy (NAION), a condition where blood flow to the optic nerve is suddenly blocked, leading to partial or complete vision loss. One patient developed papillitis, an inflammation of the optic nerve, while another suffered from paracentral acute middle maculopathy, a retinal condition that can cause blind spots.

“We’re trying to elucidate if being on these drugs can increase your risk,” said Dr. Norah Lincoff, a neurologist at the University of Buffalo and co-author of the study. “The message to the patient is that we are still investigating.”

Similar findings were reported in a different study in 2024 by scientists at the University of Harvard. Of the people included in the study with type 2 diabetes, 17 NAION events occurred in patients who were prescribed semaglutide, compared with six who were on other diabetes drugs.

The patients, all in their 50s and 60s, had preexisting conditions like diabetes and obesity, which themselves can contribute to vision problems. This overlap complicates the picture, making it difficult to establish a direct causal link between the drugs and the eye conditions.

Still, the findings are troubling. NAION, in particular, is often permanent. It’s like a stroke of the optic nerve. Once the damage is done, it’s usually irreversible.

What Could Explain This?

So, how might these drugs, designed to regulate blood sugar and suppress appetite, lead to vision loss? One leading theory points to the rapid correction of hyperglycemia — high blood sugar — that these medications induce.

“In some cases, it is hypothesized 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,” the JAMA Ophthalmology study authors wrote.

Dr. Christoph Buettner, an endocrinologist at Rutgers Robert Wood Johnson Medical School, likened the phenomenon to other medical scenarios where rapid changes in the body can have unintended consequences. “Rapid correction of high blood pressure has been linked to retinopathy and papillitis,” he said. “It’s not entirely surprising that something similar could happen with blood sugar.”

This hypothesis aligns with the experiences of diabetic patients, who often report temporary blurring of vision when their blood sugar levels fluctuate. However, the vision loss associated with NAION and other conditions is far more severe and typically permanent.

What Patients Need to Know

For the millions of people taking these medications, the findings raise important questions. Should they stop using Ozempic or similar drugs? The answer, for now, is no — but caution is advised.

“To be perfectly clear, I would not take my findings and use them to recommend that patients stop taking their medications,” Dr. Joseph Rizzo, an ophthalmologist at Mass General Brigham, told The Independent. “Our finding was really the first possible significant negative finding with these drugs. It may just merit extra caution.”

Novo Nordisk, the maker of Ozempic and Wegovy, has pushed back against the claims. In a statement, a spokesperson said, “NAION is not an adverse drug reaction for the marketed formulations of semaglutide as per the approved labels.” The company emphasized that its own analyses of clinical trials found no causal relationship between the drugs and NAION.

Still, experts urge patients to remain vigilant. “If a patient on one of these medications calls you and says that there is blurring or vision loss, have them see their ophthalmologist as soon as possible,” Dr. Lincoff advised. “Don’t wait.”

The potential risks must be weighed against the profound benefits these drugs offer. Semaglutide and tirzepatide have been shown to significantly reduce blood sugar levels, aid in weight loss, and even lower the risk of cardiovascular events. For many, they are life-changing.

But as their popularity grows — nearly 2% of the U.S. population received a prescription for semaglutide in 2023 — so does the need for rigorous scrutiny. “This is worthy of investigation,” said Dr. Howard Krauss, a surgical neuro-ophthalmologist at Providence Saint John’s Health Center in Santa Monica.

If you or someone you know is experiencing vision changes while taking weight-loss medications, consult a healthcare professional immediately.