Can Semaglutide Cause Vision Loss? A Case of Optic Nerve Damage and What the Evidence Shows | Research

The takeaway

A diabetic patient developed sudden vision loss from optic nerve damage (NAION) while on semaglutide, but the evidence linking GLP-1 drugs to this condition remains conflicting and inconclusive.

Conflicting evidence
Clinical trials found no NAION signal with semaglutide, but a retrospective study suggested a possible link. Subsequent studies have produced opposing results, leaving the question unresolved.

What the researchers found

A diabetic patient developed non-arteritic anterior ischemic optic neuropathy (NAION) — a condition that causes sudden, painless vision loss due to reduced blood flow to the optic nerve — while taking semaglutide. The authors reviewed the existing literature on this possible association and found conflicting results: the original semaglutide clinical trials did not show increased NAION risk, but a subsequent retrospective cohort study suggested a possible link. The overall evidence remains controversial, with studies presenting opposing conclusions.

Why it matters

With tens of millions of people now taking GLP-1 receptor agonists like semaglutide for diabetes and weight loss, even rare side effects become significant public health questions. NAION, while uncommon, causes irreversible vision loss. If GLP-1 drugs increase NAION risk — even slightly — this would affect risk-benefit calculations for millions of patients. The conflicting evidence makes this a clinically urgent question that requires larger, well-designed studies to resolve.

The numbers in context

1 case reported · Clinical trials: no significant NAION increase · 1 retrospective study suggested association · Multiple subsequent studies with conflicting results

How the study worked

The authors present a single case report of NAION in a diabetic patient on semaglutide and conduct a narrative review of published literature examining the potential association between GLP-1 receptor agonists and NAION, including original clinical trial data and subsequent observational studies.

Who was studied

A single diabetic patient who developed NAION while taking semaglutide, plus a review of the broader literature

What this study cannot tell us

This is a single case report, which cannot establish causation. The patient had diabetes — itself a risk factor for NAION — making it impossible to attribute the event specifically to semaglutide. The literature review is narrative, not systematic, and the existing evidence is conflicting with no definitive answer. Confounding factors (diabetes, cardiovascular risk, other medications) complicate interpretation of all available studies.

How to read the evidence

This combines a single case report (the weakest form of evidence) with a narrative literature review of studies that present conflicting conclusions. No definitive causal relationship has been established between GLP-1 drugs and NAION.

When this study was published

Published in 2025, this case report and review is timely given the ongoing debate about GLP-1 receptor agonists and NAION risk that intensified after a high-profile 2024 retrospective study. Larger prospective studies are needed to resolve the controversy.

The bigger picture

This question gained widespread attention after a 2024 retrospective study from a major academic center suggested GLP-1 receptor agonists might increase NAION risk. Given that NAION is the most common acute optic neuropathy in people over 50 and GLP-1 drugs are among the most prescribed medications globally, even a small increase in risk could affect thousands of patients. The controversy highlights the challenge of detecting rare adverse events that may not appear in clinical trials but emerge as medications reach massive real-world populations.

Questions still open

Is the apparent association between GLP-1 drugs and NAION driven by the medications themselves, or by confounding factors like diabetes and obesity that are common in patients taking these drugs?
Are certain patients (e.g., those with small optic discs or cardiovascular risk factors) more vulnerable to NAION while on GLP-1 therapy?
Should ophthalmologic screening be recommended before or during GLP-1 receptor agonist treatment?

Common questions

What is NAION and why is it concerning?

NAION (non-arteritic anterior ischemic optic neuropathy) occurs when blood flow to the optic nerve is disrupted, causing sudden, painless vision loss — usually in one eye. The damage is typically permanent, with no proven treatment to restore lost vision. It's the most common acute optic neuropathy in people over 50.

Should I stop taking semaglutide because of this risk?

The evidence linking semaglutide to NAION is conflicting and inconclusive. Clinical trials did not show an increased risk. One case report does not prove a connection, especially since the patient had diabetes — itself a NAION risk factor. Talk to your doctor about your individual risk factors rather than stopping medication based on this preliminary evidence.

Read the original research

Non arteritic ischemic optic neuropathy in a patient taking semaglutide: Is there a relation? A case report and a review of the literature.

European journal of ophthalmology, 35(4), NP10-NP15

View on PubMed ↗Publisher’s paper ↗

Citation

Maceroni, Martina; Sasso, Paola; Giarletti, Matteo; Bruno, Valentina; Minnella, Angelo Maria. (2025). Non arteritic ischemic optic neuropathy in a patient taking semaglutide: Is there a relation? A case report and a review of the literature.. European journal of ophthalmology, 35(4), NP10-NP15. https://doi.org/10.1177/11206721251331655