FDA data links semaglutide to elevated vision impairment risk

Researchers at the University of Bern have identified a troubling pattern in FDA safety reports: people taking semaglutide report vision problems at significantly higher rates than those on other diabetes and weight loss medications. The finding emerged from an analysis of more than 300,000 adverse event reports submitted to the FDA, and it arrives as semaglutide—sold as Ozempic for diabetes and Wegovy for weight loss—has become one of the most widely prescribed drugs in the world.

The Swiss team combed through the FDA's Adverse Event Reporting System, a database where doctors, patients, and manufacturers voluntarily report suspected drug side effects. Among 11,558 reports involving semaglutide, they identified 417 cases specifically mentioning vision problems, retinopathy, or ischemic optic neuropathy—a potentially sight-threatening condition affecting the optic nerve. When they compared this to other medications in the same class, semaglutide stood out. It showed a markedly higher reporting rate of vision impairment than other GLP-1 receptor agonists, as well as older diabetes drugs like metformin and DPP-4 inhibitors. The only exception was topiramate, a weight loss medication with an even higher vision impairment signal.

What makes this finding particularly significant is that the vision risk persisted even after researchers adjusted their analysis for age, sex, and existing diabetic retinopathy—the eye damage that commonly accompanies diabetes itself. This suggests semaglutide's association with vision problems is not simply a reflection of the underlying disease. The team also noticed that patients with pre-existing eye conditions appeared overrepresented in the vision impairment reports, hinting that the drug might worsen vulnerabilities in eyes already compromised by other conditions.

The concern about semaglutide and vision is not entirely new. A 2024 study of more than 16,000 patients followed over six years found the drug could increase the risk of non-arteritic anterior ischemic optic neuropathy. That study reported hazard ratios of 7.64 for patients with obesity and 4.28 for those with type 2 diabetes. Additionally, the SUSTAIN-6 clinical trial—one of the major pre-approval studies—documented retinopathy complications in 3.0 percent of semaglutide users compared to 1.8 percent receiving placebo, though most other trials did not flag significant vision problems.

The discrepancy between what pre-approval trials found and what the FDA database now reveals underscores a fundamental limitation of clinical trials: they are typically too small and too short to catch rare but serious side effects. Real-world data, collected after a drug reaches the market, can surface signals that controlled studies miss. In this case, the post-marketing surveillance suggests vision impairment may be more common than the trials indicated.

The researchers also observed that rapid weight loss—more than 10 percent of body weight in six months—correlated with higher reports of vision impairment, raising the possibility that the metabolic shifts triggered by semaglutide might play a role in ocular complications. However, the study could not establish causation, only association. The analysis has limitations: the FDA database relies on voluntary reporting, which can introduce bias; patient records are often incomplete; and the study could not calculate absolute rates of vision complications, only relative odds compared to other drugs.

Despite these constraints, the findings have prompted the researchers to call for enhanced monitoring. Healthcare providers should now be alert to vision complaints in patients taking semaglutide, particularly those with existing eye disease or those experiencing rapid weight loss. The study was published in BMC Medicine and focused primarily on semaglutide formulations for diabetes, as reports for the obesity-specific version were limited. As semaglutide use continues to expand globally, the question of whether its benefits outweigh these ocular risks—and how to identify which patients face the greatest danger—remains open.