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Weight-loss jabs could increase risk of condition causing blindness

Harvard University professors say that weight-loss injections could lead to blindness, but suggest findings are still ‘tentative’

People prescribed weight-loss injections could be at a higher risk of developing an eye condition leading to blindness, according to a new study.

Researchers at Harvard University found that people with diabetes who were prescribed semaglutide, commonly known under the brand names Wegovy and Ozempic, were four times more likely to be diagnosed with an eye condition known as non-arteritic anterior ischemic optic neuropathy (NAION). 

Joseph Rizzo, professor of ophthalmology at Harvard medical school who led the study, said: ‘The use of these drugs has exploded throughout industrialised countries and they have provided very significant benefits in many ways, but future discussions between a patient and their physician should include NAION as a potential risk.’

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NAION is a disorder in which the arteries which supply blood to the optic nerve in the eye become blocked. The condition can lead to loss of eyesight due to the optic nerve being deprived of oxygen and subsequently damaged. The condition affects 10 out of 100,000 people in the general population and there is currently no known treatment for it.

The study looked 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 within the study, 710 had type-2 diabetes, with 194 of those patients having been prescribed semaglutide. Over three years, 8.9% of these people on semaglutide had NAION compared with 1.8% on other diabetes drugs.

There were 975 patients who were overweight or living with obesity, with 361 of these having been prescribed semaglutide. A total of 6.7% of these people on semaglutide had NAION compared with 0.8% who were taking other weight-loss drugs.

But Professor Rizzo said while the findings were ‘significant, they are also tentative and future studies are needed to examine these questions in a much larger and more diverse population’.

Graham McGeown, honorary professor of physiology at Queen’s University Belfast also agreed with this and said: ‘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 always need to be balanced against likely benefits.’

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 about adverse events from use of our medicines very seriously.

‘Non-arteritic anterior ischemic optic neuropathy is not listed as a known adverse drug 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 management) as per the approved labels.’