NEW WARNING: Weight loss drugs may induce eyesight loss
In this DML Report…
A 2025 study published in JAMA Ophthalmology reported nine new cases of U.S. patients experiencing vision loss after using semaglutide (found in Ozempic and Wegovy) or tirzepatide (in Mounjaro), with seven diagnosed with non-arteritic anterior ischemic optic neuropathy (NAION), a condition involving inflammation and blocked blood flow to the optic nerve that can lead to severe or permanent blindness.
The link was first identified in 2024, and researchers suggest the cause may involve rapid blood sugar reduction damaging eye blood vessels, though the exact mechanism remains unclear. Approximately one in 10,000 patients on GLP-1 drugs like these may be affected, and NAION incidence has tripled over the past decade amid rising use of such medications. The patients in the study averaged 57 years old, with 56 percent being women, and hailed from states including Utah, Minnesota, New York, West Virginia, and Ohio. NAION affects about 6,000 Americans annually in the general population, with higher risks among those with diabetes, high blood pressure, or sleep apnea, conditions that already strain blood vessels.
Specific cases included a woman who lost vision in her left eye after one semaglutide dose for diabetes, recovered after stopping for two months, but lost sight in her right eye two weeks after restarting; another woman on semaglutide for a year developed a painless shadow over her left eye due to damaged retinal vessels; a man on tirzepatide for a year suffered left-eye bleeding; a woman in her 50s experienced painful NAION the day after her first semaglutide injection, with optic nerve swelling and retinal damage, recovering two months after stopping but relapsing upon restart and fully recovering seven months later; a man in his 60s had blurred vision and optic nerve swelling 10 months into semaglutide use, with retinal bleeding, losing vision in both eyes but recovering 10 weeks after discontinuation; and a woman in her 30s developed swollen optic nerves and hemorrhages in both eyes three months after starting semaglutide. In most cases, vision improved within days to weeks of discontinuing the medication.
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Novo Nordisk, manufacturer of Ozempic and Wegovy, initially stated blindness was not a known side effect but has since acknowledged the risk. The UK's Medicines and Healthcare products Regulatory Agency (MHRA) updated semaglutide product information to include NAION as a potential complication and advised patients to seek urgent medical care at an eye clinic or emergency department for sudden vision impairment or rapid worsening in one or both eyes.
MHRA Chief Safety Officer Dr. Alison Cave noted the risk is extremely small but emphasized vigilance for patients and providers. Harvard genetics professor Dr. David Sinclair described NAION as an "eye stroke" where individuals may wake up blind and is developing a gene-based anti-aging treatment to regenerate optic nerves, which has restored vision in animal models and could potentially reset the body in six weeks. Tirzepatide has become the leading weight-loss drug in the U.S., surpassing semaglutide.