Weight-loss drugs may cause serious eye diseases leading to vision loss in some people, two new studies suggest.
One study, published in JAMA, assessed data from nearly 1.5 million people and found that there was an increased risk of optic nerve disorders in people with diabetes taking medication such as semaglutide or tirzepatide.
The research specifically flags a rare but devastating condition called non-arteritic anterior ischaemic optic neuropathy, or NAION, wherein blood flow to the optic nerve is suddenly reduced or blocked, leading to an “eye stroke”. Patients notice it only after they lose vision in one eye, researchers write in The Conversation.
There is no treatment for the condition.
A previous study noted there was a one in 10,000 chance of a patient developing NAION as a side effect of semaglutide medication. But the latest research found that 35 of the 159,000 people with type 2 diabetes taking semaglutide or tirzepatide – about 1 in 2,500 – developed NAION.
“During the two-year follow-up, there were 35 patients with NAION in the semaglutide or tirzepatide group,” the researchers said. “There were 93 patients with other optic nerve disorders.”
Another large study of 185,000 people, published in the same journal, links weight-loss drugs known as GLP-1 RAs to an elevated risk of diabetic retinopathy, which refers to blood vessels in the retina getting damaged.
Participants on GLP-1 drugs in both studies, however, saw fewer vision-threatening complications from diabetic retinopathy and required less invasive eye treatments compared to those taking other diabetes medications, the researchers noted.
Although researchers say the overall risk of developing such conditions from taking the drugs is low, they call for closer monitoring.
They also call for further long-term studies to understand how weight-loss drugs can lead to eye complications.
“The cost of GLP-1 RAs must be weighed against the potential of these agents to lower the costs associated with the treatment of diabetes and its complications,” researchers said.
The latest research suggests that all diabetes patients given weight-loss drugs, regardless of pre-existing diabetic retinopathy, should be regularly screened and monitored for potential complications.
