In the media, there appeared news about possible side effects on vision from semaglutide, known to most as "Ozempic." This is a drug used for diabetes and obesity.
Behind these news are two scientific articles: one was published half a year ago, and the second — at the end of January. We decided to look inside what is there.
Scientists from Harvard Medical School studied patient records over five years and divided them into two groups: with type 2 diabetes and with obesity. Each of them they divided into two subgroups: those who took semaglutide and those who did not take.
In subgroups with semaglutide, the risk of non-arteritic anterior ischemic optic neuropathy (NAION) was higher by 4.28 times in diabetes and by 7.64 times in obesity.
The study had a large sample size (710 patients with diabetes and 979 patients with obesity) and high-quality statistical analysis. But it is necessary to consider its limitations.
The work was conducted in a neuro-ophthalmology clinic among patients with an average age of 47 years, who by definition sought help with vision problems. Therefore, the sample does not reflect the image of a typical patient at an endocrinologist's appointment.
The baseline prevalence of NAION is low (2–10 cases per 100,000 population), which requires greater study power to exclude other factors that could influence the result.
Moreover, such a study by its design allows establishing only an association between the use of the drug and risk, but not a causal relationship. That is, the article does not answer the question: does semaglutide increase the risk of blindness?
The author of the second study surveyed 800 neuro-ophthalmologists to find cases of NAION development after taking semaglutide.
He was able to find:
– seven cases of NAION development: four patients took semaglutide, three — a new drug with a similar mechanism of action tirzepatide.
– one case of vision loss due to paracentral acute middle maculopathy
– one case of optic papillitis with preserved acute vision.
Most patients were older than 50 years and had additional risk factors.
This study is a description of a series of clinical cases. From it too, no conclusions can be drawn that semaglutide or tirzepatide cause vision impairment.
Then why are these articles needed?
These studies raise important questions for science. But they do not provide any answers at all about:
– whether semaglutide increases the risk of NAION?
– if it increases — by how much?
– does the risk of NAION outweigh the benefit of semaglutide — reducing the risk of diabetic retinopathy?
Therefore, it is important to wait for future works that will evaluate data on side effects 🔥
The situation itself with finding associations between a drug and a side effect is not news for the world of science.
Adverse reactions, including serious ones, exist for many other drugs, for example, antibiotics. But they happen very rarely, and the benefits of drugs outweigh the risks.
The hype in the media may be related to semaglutide being a relatively new and very popular drug in media.
Are there any assumptions about how semaglutide might affect vision?
A sharp reduction in glycated hemoglobin may be associated with worsening diabetic retinopathy — a very common complication of diabetes.
Scientists suggest that such a mechanism may also participate in NAION development. Therefore, doctors need to remember about the importance of gradual glycemia reduction.
What should patients do?
🔥 If you are taking semaglutide as prescribed by your doctor — do not stop the drug on your own because of news. Follow your doctor's recommendations.
The American Academy of Ophthalmology responded to the first article by publishing its position. They do not recommend stopping semaglutide and other similar drugs. And if vision starts to worsen — you need to see a doctor.
🔥 Do not take semaglutide without a doctor's prescription. Although technically buying the drug in pharmacies without a prescription is possible, it still is prescription-based.
