People prescribed a weight-loss injection may be at increased risk of developing an eye condition that can lead to blindness, a study has found.
The study found that people with diabetes who were prescribed semaglutide, commonly known by the brand names Wegovy and Ozempic, were more than four times more likely to be diagnosed with an eye condition known as non-arteritic anterior ischemic optic neuropathy (naion).
Naion is a disorder in which the arteries that supply blood to the optic nerve in the eye are blocked. The condition can lead to vision loss due to the optic nerve being deprived of oxygen and subsequently damaged. There is no known treatment for the condition, which affects 10 in 100,000 people in the general population.
The research, published in the journal JAMA Ophthalmology and conducted by researchers at Harvard Universitylooked at data from 16,827 patients at the Mass Eye and Ear Harvard Teaching Hospital, who received treatment over a six-year period.
Of the patients included in the study, 710 had type two diabetes, with 194 of those patients prescribed semaglutide, which is the active ingredient in brands including Wegovy and Ozempic.
Included in the study were 975 patients who were overweight or living with obesity, with 361 of them prescribed semaglutide.
Of the people included in the study with type 2 diabetes, 17 naion events occurred in patients prescribed semaglutide, compared with six who used other diabetes drugs.
Over three years, 8.9% of these people on semaglutide had naion compared to 1.8% on the other drugs, the researchers found.
The study also found that people who were overweight or living with obesity who were prescribed semaglutide were more than seven times more likely to develop the condition than those on other types of weight loss drugs.
Of the people included in the study who were overweight or obese, 20 naion events occurred in people prescribed Semaglutide, compared to just three events in people taking other drugs.
Over three years, 6.7% of these people on semaglutide had naion compared to 0.8% who used other weight loss drugs.
Prof Joseph Rizzo, a professor of ophthalmology at Harvard Medical School, said: “Our findings should be considered significant but preliminary, as future studies are needed to investigate these questions in a much larger and more diverse population.
“This is information we didn’t have before and it should be included in discussions between patients and their doctors, especially if patients have other known optic nerve problems such as glaucoma or if there is significant pre-existing visual 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 one form of sight-threatening optic neuropathy, but this would ideally be tested in larger studies.
“Given the rapid increase in semaglutide use and its possible licensing for a range of problems other than obesity and type 2 diabetes, this issue deserves further study, but possible drug side effects must always be balanced against likely benefits.”
Semaglutide under the brand name Wegovy is prescribed for weight loss on the NHS since 2023.
Novo Nordisk, the manufacturer of Wegovy and Ozempic, has been contacted for comment.
