GLP-1 drugs and blindness have been linked in users of GLP-1 receptor agonist drugs — including Ozempic, Wegovy, Mounjaro, Zepbound, Rybelsus, Trulicity, Saxenda, and Victoza. Studies have linked and report of sudden vision loss, including a serious condition known as Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION). NAION is a medical emergency that can cause permanent blindness, often without warning. As reports of vision loss following GLP-1 use increase, legal investigations and state court and federal court litigation (Multidistrict litigation) have expanded to address this distinct and severe injury category.
This page explains what NAION is, how it may relate to GLP-1 drugs, symptoms to watch for, and when legal action may be appropriate.
What Is NAION?
Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION) occurs when blood flow to the optic nerve is suddenly reduced, causing damage to the nerve fibers responsible for vision.
Key characteristics:
- sudden, painless vision loss
- often occurs upon waking
- usually affects one eye, but can affect both
- vision loss is often permanent
- no reliably effective treatment exists
NAION is one of the leading causes of sudden optic nerve–related blindness in adults over 40.
NAION is a devastating ocular diagnosis that often leads to permanent loss of vision. Non-arteritic anterior ischemic optic neuropathy pertains to losing blood flow to the optic nerve. The optic nerve is a cable with connectivity to the eye and the brain. NAION usually results in vision loss in one eye without warning. This condition is painless. In some incidences, people become aware of major vision loss in one eye-right after getting up in the am. The vision loss usually stays mostly stable, without improving or getting worse after it has occurred.
Non-arteritic anterior ischemic optic neuropathy (NAION) results from impaired blood circulation in the front of the optic nerve. The “non-arteritic” component pertains to lesser blood flow with no real inflammation of the blood vessels (as typified in arteritis). The reason it is name “anterior” is because reduced blood flow and trauma to the optic nerve occurs at the most front portion of the nerve. This is where the nerve connects with the eye. The reason this is named “ischemic” is because that best describes the trauma resulting from lower blood flow. Lastly, it is named “optic neuropathy” because it is trauma to the optic nerve. This injury wreaks havoc with the ability of the eye to impart information to the brain.
With NAION, it is hard to pinpoint the reason why there is reduced blood flow to the optic nerve. NAION can often be caused by conditions like diabetes, GLP-1 use, high blood pressure, and sleep apnea. Smoking could increase the chance of a NAION diagnosis. The majority of patients with a NAION diagnosis have an anatomical variation of the optic nerve. This makes its contents crowded and extremely tight. This anatomy reality may very well add to impaired circulation that leads to NAION.
The 2024 Harvard Study That Started It All — And What the Research Has Shown Since
The scientific foundation for the growing wave of Ozempic and Wegovy vision-loss litigation traces back to a July 2024 study published in JAMA Ophthalmology by researchers at Massachusetts Eye and Ear, a Harvard-affiliated teaching hospital. The retrospective cohort study, led by Dr. Jimena Tatiana Hathaway, examined nearly 17,000 patients evaluated at a single neuro-ophthalmology practice and found that semaglutide patients faced a more than fourfold increased risk of nonarteritic anterior ischemic optic neuropathy (NAION) if being treated for type 2 diabetes, and a more than sevenfold increased risk if being treated for obesity, compared to patients on non-GLP-1 alternatives. NAION causes sudden, permanent, and currently untreatable vision loss, and the study’s authors were careful to frame their findings as an association requiring further research, not proof that semaglutide causes the condition. That caveat, however, did little to slow what followed.
In the eighteen months since the Hathaway study’s publication, the medical and regulatory response has been substantial. The European Medicines Agency opened a formal safety review of semaglutide and NAION in January 2025, and by June 2025 the agency had concluded the review by classifying NAION as a very rare side effect of semaglutide and recommending corresponding updates to the drug’s product labeling in Europe. Independently, pharmacovigilance researchers mining the FDA’s Adverse Event Reporting System identified a statistically disproportionate signal of NAION reports associated with semaglutide, including a notable surge in reports originating from Denmark in the final months of 2024, further fueling regulatory attention on both sides of the Atlantic.
Perhaps more significant for litigation purposes than the original single-center study is what came after it: a series of larger, methodologically varied replication attempts. A major 2025 study led by Dr. Cindy Cai and colleagues, also published in JAMA Ophthalmology, used the OHDSI research network to examine the semaglutide-NAION question across 14 separate databases, six administrative claims databases and eight electronic health record systems, representing a dramatically larger and more diverse dataset than the original Harvard cohort. Around the same time, a separate 2025 study by Dr. Alan Hsu and colleagues, again in JAMA Ophthalmology, was described by commentators as the largest study of the association to date. Notably, results across this expanding body of research have not been uniformly consistent, prompting an accompanying JAMA Ophthalmology editorial titled “Conflicting Results — Need for More Transparent and Reproducible Research,” a pointed acknowledgment from the journal itself that the picture remains scientifically unsettled even as it continues to sharpen.
Additional corroborating evidence has since emerged from multiple independent populations. A Danish-Norwegian cohort study published in Diabetes, Obesity and Metabolism in 2025 examined national registry data across two countries. A multinational population-based study published in the journal Ophthalmology similarly evaluated the association across several countries’ health systems. And in one of the most methodologically robust analyses to date, a U.S. Department of Veterans Affairs study published in JAMA Ophthalmology followed more than 102,000 veterans with type 2 diabetes for up to 7.5 years, comparing those started on semaglutide against those started on an SGLT2 inhibitor. That study found NAION developed in roughly 0.29% of semaglutide patients compared to 0.13% of SGLT2 inhibitor patients, a roughly twofold relative increase, notably smaller than the fourfold to sevenfold hazard ratios reported in the original Harvard study, but still a statistically meaningful signal drawn from the longest follow-up period and one of the largest patient populations studied to date. A 2025 systematic review and meta-analysis, also published in JAMA Ophthalmology, has since attempted to pool this expanding body of evidence into a single aggregated risk estimate.
For attorneys evaluating or litigating semaglutide-related vision loss claims, this expanding research record cuts in more than one direction. On one hand, the fact that multiple independent research teams, using different databases, different countries, different comparator drugs, and different methodologies, have now repeatedly identified an elevated NAION signal considerably strengthens a general causation argument beyond what a single-center study could support on its own, and the EMA’s formal regulatory finding adds meaningful weight as an independent, non-litigation-driven determination. On the other hand, the acknowledged inconsistency between studies, the JAMA editorial explicitly flagging conflicting results, the comparatively modest relative risk found in the largest and longest VA analysis, and the persistently low absolute risk to any individual patient are exactly the vulnerabilities defense experts are likely to emphasize in challenging plaintiffs’ general causation showing. As this litigation moves through early bellwether and Daubert-stage proceedings, expect both sides to lean heavily on this now-substantial and still-growing body of post-2024 research to make their respective cases.
GLP-1 Drugs and Blindness specific to Vision Loss for Medication Users
In recent years, physicians and patients have reported cases of:
- sudden partial or total blindness
- blurred or dim vision
- loss of peripheral vision
- visual field defects
- optic nerve swelling (optic disc edema)
These reports have triggered:
- increased pharmacovigilance scrutiny
- medical literature discussion
- federal multidistrict litigation (MDL) focused on vision loss claims
Recent research indicates a causal link between GLP-1 receptor agonists and severe eye damage. These eye injuries specifically include sudden vision loss caused by Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION). Eye damage may include deteriorating diabetic retinopathy, and a possible increase in wet macular degeneration. Even though medical benefits usually outweigh the known risks, patients should watch for changes in vision and seek treatment from an ophthalmologist if patients endure blurred or lessened vision.
While causation is still under investigation, medical experts are evaluating several plausible mechanisms, including:
Blood Pressure and Perfusion Changes
GLP-1 drugs can:
- lower blood pressure
- alter vascular tone
- affect nocturnal hypotension
Reduced blood flow during sleep is a known risk factor for NAION.
Dehydration and Volume Depletion
GLP-1 drugs commonly cause:
- vomiting
- reduced fluid intake
- dehydration
Dehydration can reduce optic nerve perfusion, increasing ischemic risk.
Rapid Metabolic Changes
Rapid weight loss and glycemic shifts may:
- alter microvascular circulation
- increase susceptibility in patients with “crowded” optic discs
Who May Be at Higher Risk
NAION risk factors include:
- diabetes
- hypertension
- sleep apnea
- cardiovascular disease
- smoking history
- age over 40
- anatomical optic nerve susceptibility
Many GLP-1 users fall into multiple overlapping risk categories, making risk stratification especially important.
Patients over 50 who have cardiovascular risk factors—such as hypertension, diabetes, high cholesterol, and obstructive sleep apnea—have the greatest risk of a Nonarteritic Anterior Ischemic Optic Neuropathy (NAION) diagnosis. Additional risk factors are: small optic nerve cups (“disc at risk”), smoking, smoking-related medical problems, and drugs such as PDE-5 inhibitors (Viagra, Amiodarone).
Symptoms That Require Immediate Medical Attention
Seek emergency ophthalmologic care if you experience:
- sudden vision loss in one or both eyes
- dark or missing areas in your field of vision
- blurred or dim vision upon waking
- loss of color perception
- visual “shadows” or curtains
Vision loss can become permanent within hours.
NAION as a Separate Legal Injury Category
Vision loss cases are legally distinct from GI injury cases because:
- blindness is often permanent
- damages are severe and lifelong
- causation analysis differs
- specialized ophthalmology experts are required
As a result, NAION claims are being handled in a separate federal MDL from gastroparesis and GI cases. The NAION lawsuits are being filed in MDL 3163-“In Re: Glucagon-like Peptide-1 Receptor Agonists (GLP-1 RAs) Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION) Products Liability Litigation.” The actions in this multidistrict litigation (“MDL”) (MDL No. 3163) involve injuries stemming from the use of glucagon-like peptide-1 receptor agonists (“GLP-1 RAs”), which are medicines prescribed for, among other things, the treatment of type 2 diabetes and chronic weight management. This class of medications includes Ozempic, Wegovy, and Saxenda, which are manufactured by the Novo Nordisk Defendants, and Trulicity, which is manufactured by Eli Lilly and Company.
➡️ Related legal hub: MDL
Criteria to file a GLP-1 vision loss lawsuit
(Who qualifies for an Ozempic vision loss lawsuit?)
Vision Changes (sudden or severe after taking GLP-1RA medication. Must have a diagnosis):
- Sudden blindness
- Visual acuity loss
- Optic nerve stroke
- Color blindness
- Retinal stroke
- Reduced sharpness or clarity of vision leading to difficulty seeing detailed objects or distances clearly.
- Eye Injury occurred within a time span of about a month.
- Severe or Sudden onset worsening of vision
- Eye Injury occurred within a time span of about a month (30 days+-)
- Ischemia to optic nerve
- Wet macular degeneration
For vision injury or Ozempic vision loss lawsuits, we are not accepting primary diagnosis of floaters, diabetic retinopathy, cataracts or glaucoma. (Unless the client experiences sudden blindness in one eye or it’s a NAION lawsuit)
What Evidence Matters in Vision Loss Claims
Strong NAION claims often include:
- ophthalmology and neuro-ophthalmology records
- optic nerve imaging (OCT, fundus photos)
- visual field testing
- ER or urgent ophthalmology visits
- documentation of sudden onset
- GLP-1 prescription history
Do You Need an FDA Report to File a Claim?
No. FDA reports are not required.
Legal claims focus on:
- medical diagnosis
- severity and permanence
- timing relative to drug use
- functional impact
When to Consider a Legal Review
You may qualify for a review if:
- you used a GLP-1 drug, AND
- you experienced sudden vision loss or NAION, AND
- symptoms were diagnosed by an eye specialist, AND
- vision did not fully recover
➡️ Start here: File a Claim
NAION is a devastating, often permanent form of blindness that has been reported in connection with GLP-1 drug use. GLP-1 drugs and blindness or vision loss often causes lifelong impairment, these cases are treated as one of the most severe injury categories in current GLP-1 litigation.
If you experienced sudden vision loss after using a GLP-1 drug, early medical and legal review is critical.