Health Network》Slimming injection may cause eye stroke, doctors reveal the risk of blindness. 3 symptoms, don’t delay seeking medical treatment

Chen Yufu, a gastroenterology and hepatobiliary specialist at Ririqing Clinic, pointed out that multiple studies have found that semaglutide is related to ocular stroke, but correlation does not mean causation. He reminded that if the three warning signs appear, you should seek medical treatment as soon as possible.

Concerns have arisen over whether slimming injections may cause blindness, and a suspected case of eye stroke has also been reported in Taiwan recently. Chen Yufu, a gastroenterology and hepatobiliary specialist at Ririqing Clinic, pointed out that multiple studies have found that semaglutide is associated with optic nerve ischemia called NAION (often called "eye stroke"). The relative risk is about 1.3-2 times, but the absolute risk is very low. However, correlation does not mean causation. If you suddenly experience 3 warning signs such as vision loss or visual field loss that is not painful in one eye, you should seek medical attention as soon as possible.

Chen Yufu posted on his Facebook page that in conclusion, blindness caused by weight-loss injections is extremely rare. A comprehensive analysis in 2026 estimates that there will be about 1 additional case for every 7,000 drug users every year. The certainty of the evidence is low to very low. It is not that "you will go blind after taking weight loss injections" because people who need to take drugs often have risk factors such as diabetes, high blood pressure, and sleep apnea. As for a frequently reposted study from a U.S. referral center, the relative risk appears to be higher, but it was for ophthalmology referral patients and cannot represent the actual risk in general outpatient clinics.

Chen Yufu explained that the conclusions of clinical trials are not consistent because there are too few cases. The US FDA combined 126 trials and saw 10 "probable" cases compared to 5; another analysis of confirmed cases found no imbalance. The FDA has required all GLP-1 drugs to carry warnings on November 9, 2026, recommending that "consider discontinuing the drug unless the benefits clearly outweigh the risks." The EU EMA classifies this side effect of semaglutide as extremely rare (at most about 1 case per 10,000 people), and the drug should be discontinued after diagnosis. As for the Taiwan Food and Drug Administration, it has issued a risk communication in June 2025 and will require Chinese labeling in June 2026.

Chen Yufu reminded that if you suddenly have painless blurred vision in one eye or a missing piece of visual field, which is often discovered when you get up in the morning, or the color becomes pale and the center is unclear, you should seek medical treatment as soon as possible and do not observe at home. People who have had it happen in one eye are also at higher risk in the other eye, so they can take the initiative to tell their doctor before taking medicine.

Chen Yufu emphasized that if the above symptoms do not occur, do not stop taking the medicine on your own because of the news; if the diagnosis is confirmed, discuss with the doctor whether to stop taking the medicine. In addition, those who have diabetes themselves should have routine fundus examinations as usual; worsening of diabetic retinopathy is another matter and should not be confused with NAION. He reminded that health education information cannot replace individual diagnosis and treatment, nor is it prescription advice. Medication should still be discussed with a doctor.