More research needed on possible ocular side effects of semaglutides
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Drugs utilized to treat systemic diseases can do harm to the eye and its neural connections.
With the increasing use of injected semaglutide (Ozempic, Wegovy; Novo Nordisk) for the treatment of type 2 diabetes and obesity, it is not surprising that patients taking a semaglutide when examined by an eye care professional also have one or more ocular diseases. The challenge is differentiating causation from correlation. Causation means that one event, such as being treated with a semaglutide, results in another, such as vision-threatening nonarteritic anterior ischemic optic neuropathy (NAION). Correlation is simply a random statistical finding based on the overlapping incidence and prevalence of a treatment and a disease and is not causal. For example, patients with a cataract may also have age-related macular degeneration. AMD does not cause cataract, and cataract does not cause AMD.
According to several references, there are about 6,000 new cases of NAION diagnosed each year in the U.S. With nearly 3 million Americans taking a semaglutide today, while NAION is a rare diagnosis, statistically some patients who develop AION will be on a semaglutide. With the rapidly increasing use of semaglutides in our country, we know some patients who present with NAION will be on this drug, and to add to the challenge, diabetes, hypertension, cardiovascular disease and obesity, the common indications for prescribing a semaglutide, are also risk factors for NAION. At present, we cannot conclude that semaglutide use increases the risk for NAION, but we ophthalmologists must always be vigilant and report potential drug-induced ocular side effects so they can be studied for potential causality. Our neuro-ophthalmology colleagues deserve our respect and appreciation for their clinical observations, which deserve further study.
A similar clinician observation closer to home for we anterior segment surgeons was David Chang, MD’s, original report that a syndrome characterized by a poorly dilating pupil that constricted during cataract surgery and was associated with a flaccid iris that often prolapsed (intraoperative floppy iris syndrome, IFIS) seemed to be associated with the use of alpha-1A antagonists such as tamsulosin (Flomax, Sanofi), commonly used to treat urinary outflow/obstruction from benign prostatic hypertrophy. It was later proven that an alpha-1A antagonist given orally is causal for IFIS. While this learning has not had a significant impact on the use of alpha-1A antagonists when indicated, it has significantly enhanced patient counseling and benefited physician and surgeon management.
It is our duty to determine if semaglutides increase the risk for NAION. This answer is likely best answered through a collaboration between our neuro-ophthalmology colleagues and the North American Neuro-Ophthalmology Society. It may be possible to gain insights and useful data from the American Academy of Ophthalmology IRIS Registry. I have found the team at Verana Health to be extremely helpful.
Finally, a reminder that the eighth edition of the textbook by Frederick T. Fraunfelder, MD, and Frederick W. Fraunfelder, MD, MBA, titled Drug-Induced Ocular Side Effects is available from Amazon and in my opinion belongs in every eye care professional’s personal library.
- For more information:
- Richard L. Lindstrom, MD, can be reached at rllindstrom@mneye.com.
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