GLP 1 medications first hit the market in the United States in 2005 for controlling blood sugar. In 2014 they gained the official indication for weight loss. Since that time the use of these medications has substantially expanded. About 1 in 8 adult Americans is currently taking GLP 1 therapy.
GLP 1 medications include Ozempic or Wegovy, Mounjaro or Zepbound, Saxenda, etc.
As neuro-ophthalmology community we started to notice a possible connection with events of Non-arteritic Anterior Ischemic Optic Neuropathy (NAION). But the community has been uncertain if these events are caused by the medication or not.
The FDA also monitors medication for adverse events. They came out with a warning that all GLP 1 treatments increase the risk of NAION.
What they found:
NAION is a rare condition.
In their monitoring they found that NAION occurred in about 6 in 100,000 patients treated with GLP 1 treatment. However, they also saw NAION occurred in about 3 in 100,000 who received placebo.
So, what should we make of this?
If I say something like NAION is twice as likely to occur in patients who take GLP 1 meds, that is true but it sounds a bit sensationalist. I could also say GLP 1 medication increases the patient's odds of NAION by only 0.003%. that is also true, but that sounds a bit dismissive.
I think the responsible thing is to explain it both ways.
 |
| image: the blue diamond gallery CCBY-SA3.0 |
It is important to understand probabilities. If we double the probability of an unlikely event, we still have an unlikely event.
Now, compare that unlikely event with all the other health benefits of controlling blood sugar and weight, etc which GLP 1 treatments do.
For most patients this is a straight forward decision. The low risk of an adverse event should not be the deciding factor, but the ability to control their other health condition will usually be the deciding factor.
The FDA does not recommend any form of screening exam before starting medication. There is no point. There is no definite way to predict who would have an ischemic optic nerve event.
On the other hand, if someone has already had NAION in one eye. I would be very suspicious of the GLP 1 treatment and very unlikely to recommend continuing treatment.
So, in summary, GLP 1 meds are probably associated with increased risk of ischemic optic nerve disease, but the risk remains low and most patients would be advised to continue their treatment, but if a patient has had a previous event, or an unusually high baseline risk, then that individual may be better off to avoid these treatments.