Research shows weight loss injections may be linked to condition that can cause blindness
Research has shown that people who are prescribed an injection to lose weight have a greater risk of developing an eye condition that can lead to blindness.
The study found that people with diabetes who were prescribed semaglutide, better known by the brand names Wegovy and Ozempic, were four times more likely to be diagnosed with non-arteritic anterior ischemic optic neuropathy (NAION).
Naion is a condition in which the arteries that supply blood to the optic nerve in the eye become blocked. The condition can lead to vision loss because the optic nerve is deprived of oxygen and subsequently damaged. There is no known cure for the condition, which affects 10 out of every 100,000 people in the general population.
The study, published in the journal JAMA Ophthalmology and conducted by researchers at Harvard University, looked at data from 16,827 patients at Harvard’s Mass Eye and Ear teaching hospital, who were treated over a six-year period.
Of the patients participating in the study, 710 had type 2 diabetes. Of these, 194 had been prescribed semaglutide, the active ingredient in brands such as Wegovy and Ozempic.
The study included 975 overweight or obese patients, 361 of whom were prescribed semaglutide.
Among people with type 2 diabetes who participated in the study, 17 national events occurred in patients prescribed semaglutide, compared with six in patients taking other diabetes medications.
The researchers found that 8.9% of people taking semaglutide had kidney impairment over three years, compared with 1.8% on the other drugs.
The study also found that overweight or obese people who were prescribed semaglutide were more than seven times more likely to develop the condition than people taking other types of weight-loss drugs.
Of the people in the study who were overweight or obese, 20 national events occurred in people prescribed semaglutide, compared with only three events in people taking other medications.
Over three years, 6.7% of people taking semaglutide had lost weight, compared with 0.8% of people taking other weight-loss drugs.
Prof. Joseph Rizzo, professor of ophthalmology at Harvard Medical School, said: “Our findings should be viewed as significant but preliminary, as future studies are needed to investigate these questions in a much larger and more diverse population.
“This is information that we didn’t have before and that we should be including in the conversations between patients and their doctors, especially if patients have other known optic nerve problems, such as glaucoma, or if there is pre-existing significant vision loss from other causes.”
Graham McGeown, Honorary Professor of Physiology at Queen’s University Belfast, said: “This research does suggest a link between semaglutide treatment and a form of sight-threatening optic neuropathy, but ideally this would need to be tested in larger studies.
“Given the rapid increase in the use of semaglutide and its potential approval for a range of conditions other than obesity and type 2 diabetes, this topic deserves further investigation, but potential side effects of the drug should always be weighed against its likely benefits.”
Semaglutide has been prescribed for weight loss by the NHS under the brand name Wegovy since 2023.
A spokesperson for Novo Nordisk, the maker of Ozempic and Wegovy, said: “Patient safety is a top priority for Novo Nordisk and we take all reports of side effects associated with our medicines very seriously.
“Non-arteritic anterior ischemic optic neuropathy is not listed as a known adverse reaction in the summary of product characteristics (SmPC) for the marketed formulations of semaglutide (Ozempic). and Rybelsus for type 2 diabetes and Wegovy for weight control) according to the approved labels.”