Semaglutide use is associated with increased risk of non-arteritic anterior ischaemic optic neuropathy (NAION) in type 2 diabetes patients, according to a new study.

The high-profile drug is prescribed in injectable form as Ozempic and in tablet form as Rybelsus to lower blood sugar and reduce cardiovascular risks in adults with type 2 diabetes. It is branded as Wegovy for weight loss and management.

NAION is the most common acute optic neuropathy in people aged 50 and over, affecting two to 10 individuals per 100,000 in that age group (Lee et al, 2011 ).

A team led by ophthalmologists at the University of Southern Denmark (USD) analysed the health records of more than 420,000 adults with type 2 diabetes.

After adjusting for factors such as age and illness, they found semaglutide use was associated with a more than doubling of the risk of NAION.

The average number of annual NAION diagnoses in Denmark rose from 67.6 in 2003-18 to 148 in 2019-23, when semaglutide became available.

The team was unable to control for variables such as smoking, blood pressure and body mass index. They had no access to data on drug adherence. And the increased risk of NAION in semaglutide users they identified was low in real terms, at 0.228 per 1,000 observation person-years. 

While this research found that the risk “more than doubled”, the absolute risk of NAION remained small. The increased risk of NAION should be balanced against the potential benefits of taking Ozempic.

Two other studies found no link between semaglutide and increased NAION risk in type 2 diabetes patients (Chou et al, 2024; Klonoff et al, 2024 ).

Further guidance is expected following an ongoing review by the European Medicines Agency.