GLP-1 NAION Vision Loss Lawsuit MDL 3163: Ozempic, Wegovy & Trulicity Eye Injury Claims 2026

Sudden Vision Loss After Ozempic: What Patients Need to Know

For millions of Americans, semaglutide (Ozempic, Wegovy) and other GLP-1 receptor agonists have become central tools in managing diabetes and obesity. These medications have demonstrated meaningful clinical benefits. But beginning in 2023, a serious safety signal emerged: reports of non-arteritic anterior ischemic optic neuropathy (NAION) — sudden, permanent vision loss — in patients using GLP-1 drugs.

In July 2024, a peer-reviewed study in JAMA Ophthalmology, conducted by researchers at Harvard Medical School and the Massachusetts Eye and Ear Institute (MEEI), found that semaglutide users had approximately 4 to 7 times the rate of NAION compared to matched controls. The study set off a wave of lawsuits against Novo Nordisk and Eli Lilly.

Those lawsuits were consolidated into MDL 3163 in the Eastern District of Pennsylvania, before U.S. District Judge Karen S. Marston. As of May 1, 2026, the JPML reports 86 pending actions — a number that is growing as plaintiff firms continue screening and filing cases.

This guide explains what NAION is, who may qualify to file a claim, what evidence matters, and what to expect from the MDL process. It is not legal advice.

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MDL 3163: Court, Judge, and Case Status

MDL 3163 at a Glance:

Field	Detail
Full case name	In re: GLP-1 RAs NAION Products Liability Litigation
MDL No.	3163
Court	U.S. District Court, Eastern District of Pennsylvania (E.D. Pa.)
Presiding judge	Hon. Karen S. Marston
Pending actions	86 (JPML report, May 1, 2026)
Related MDL	MDL 3094 (GLP-1 gastroparesis — separate court, separate judge)

The JPML created MDL 3163 because federal courts across the country were receiving similar complaints: GLP-1 drug users developing NAION. Consolidation in a single court before one judge allows for efficient case management, coordinated discovery from Novo Nordisk and Eli Lilly, and consistent rulings on expert witness standards.

Important: Judge Marston also presides over MDL 3094 (GLP-1 gastroparesis). Having one judge handle both MDLs provides administrative efficiency, but the two cases are procedurally and substantively separate. A NAION claim belongs in MDL 3163; a gastroparesis claim in MDL 3094. An attorney can assess whether you have viable claims in one or both.

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The Drugs at Issue

Drug Name	Generic Name	Manufacturer	Type
Ozempic	Semaglutide (injection)	Novo Nordisk	GLP-1 agonist
Wegovy	Semaglutide (injection, higher dose)	Novo Nordisk	GLP-1 agonist
Rybelsus	Semaglutide (oral)	Novo Nordisk	GLP-1 agonist
Trulicity	Dulaglutide	Eli Lilly	GLP-1 agonist
Mounjaro	Tirzepatide	Eli Lilly	Dual GIP/GLP-1 agonist
Zepbound	Tirzepatide	Eli Lilly	Dual GIP/GLP-1 agonist

Note on tirzepatide (Mounjaro/Zepbound): Tirzepatide acts on both GLP-1 and GIP receptors. It is included in the MDL because of its GLP-1 mechanism, though whether its dual-receptor profile changes the NAION risk profile is likely to be contested by experts.

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What Is NAION — and Why It Matters

Non-arteritic anterior ischemic optic neuropathy is the most common acute optic nerve disorder in adults over 50. It results from reduced blood flow to the anterior portion of the optic nerve, which is highly dependent on the small posterior ciliary arteries.

Clinical features of NAION:

• Sudden, painless vision loss — frequently noticed upon waking
• Typically affects one eye; the other eye remains at elevated risk
• Visual field loss pattern: commonly an altitudinal defect (upper or lower half of visual field gone)
• Optic disc edema visible on fundoscopic examination in the acute phase
• No effective treatment exists — vision loss is generally permanent
• Approximately 15%–24% of patients experience fellow-eye involvement within 5 years

Established risk factors:

• Small “disc at risk” anatomy (low cup-to-disc ratio)
• Hypertension, diabetes, hyperlipidemia, sleep apnea
• Age over 50
• Male sex
• Certain medications (including phosphodiesterase inhibitors like sildenafil)

The legal and scientific question in MDL 3163 is not whether these established risk factors cause NAION — they do. The question is whether GLP-1 drugs cause NAION in addition to baseline risk, and whether that additional risk was adequately communicated to prescribers and patients.

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The Harvard/MEEI Study: What It Found and Its Limitations

The 2024 JAMA Ophthalmology study is the primary scientific foundation for MDL 3163. Understanding it — including its limitations — prepares you for what both sides will argue.

Study design:

• Retrospective cohort study at a single large tertiary care academic medical center
• Compared NAION incidence in GLP-1 users vs. non-GLP-1 users being treated for type 2 diabetes or obesity
• Controlled for several established NAION risk factors

Key finding: Semaglutide users had approximately 4 to 7 times the NAION incidence compared to controls, depending on the analysis cohort (diabetes vs. obesity).

Plaintiff attorneys will emphasize:

• 4–7x relative risk is a substantial signal by epidemiological standards
• The study controlled for baseline risk factors
• The temporal relationship (drug use preceding NAION onset) supports a plausible causal pathway

Defense attorneys will argue:

• A single-center retrospective study cannot establish causation
• The study population may not be representative of all GLP-1 users
• Residual confounding (uncontrolled risk factors) may explain the association
• The absolute number of NAION cases in the study was small

These arguments will play out in Daubert hearings before Judge Marston. The court’s ruling on the admissibility and scope of plaintiffs’ causation experts will be one of the most critical early milestones in MDL 3163.

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Legal Theories: What Plaintiffs Are Claiming

Failure to Warn (Most likely path to liability):

Under the learned intermediary doctrine applicable in most states, drug manufacturers fulfill their duty to warn by adequately informing prescribing physicians of known or reasonably knowable risks. If Novo Nordisk and Eli Lilly knew — or should have known — of a materially elevated NAION risk and did not include an adequate warning in the prescribing information (package insert/label), this constitutes a failure to warn.

The current FDA-approved labels for Ozempic, Wegovy, and Trulicity do not include NAION as a recognized adverse reaction. Plaintiffs argue this omission was negligent or reckless given available safety signal data.

Negligent Post-Marketing Surveillance:

Drug manufacturers have ongoing duties to monitor their products’ safety after FDA approval. Plaintiffs may argue that AT&T signals of NAION risk in post-marketing pharmacovigilance data (FAERS database, scientific literature) were not appropriately escalated or communicated.

Design Defect:

A harder argument to win, but some plaintiffs may allege that the GLP-1 receptor agonist mechanism inherently creates an unacceptable NAION risk for certain patient populations — in which case no label change can cure the defect.

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Who Qualifies: Eligibility Checklist

Work through this checklist before contacting an attorney:

Required elements:

• Prescribed and used an Ozempic, Wegovy, Rybelsus, Trulicity, Mounjaro, or Zepbound
• Experienced sudden vision loss in one eye during or after use
• Received a confirmed NAION diagnosis from an ophthalmologist

Factors that strengthen your claim:

• Short interval between GLP-1 drug initiation (or dose escalation) and NAION onset
• Absence of or well-controlled pre-existing NAION risk factors
• Severe vision loss (large altitudinal defect, significant VA reduction)
• Fellow-eye involvement

Factors that complicate but do not necessarily defeat a claim:

• Pre-existing diabetes or hypertension (GLP-1 drugs are commonly prescribed for these)
• Use of other medications with NAION risk
• History of PDE5 inhibitor use

The key legal standard is not “the drug was the only possible cause” but “the drug was a substantial contributing factor.” This is a fact-intensive analysis — consult an attorney.

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Building Your Evidence File

Prescription and dispensing records:

• Obtain complete prescription history from your prescribing doctor(s) and pharmacy records
• Document: drug name, dose, start date, any escalation dates, stop date (if applicable)

Ophthalmology records — the most critical:

• Diagnostic report confirming NAION (date of diagnosis is key for SOL purposes)
• Optical coherence tomography (OCT) imaging showing retinal nerve fiber layer changes
• Humphrey or Goldmann visual field test results
• Fundus photographs taken at time of acute presentation
• Fluorescein angiography results (if performed)
• Follow-up records documenting permanent vision loss

Medical history records:

• Primary care records confirming presence or absence of diabetes, hypertension, sleep apnea, hyperlipidemia
• Any ophthalmology records from prior eye exams showing pre-existing cup-to-disc ratio

Economic impact documentation:

• Records documenting how vision loss affected employment, driving ability, or daily activities
• Lost income documentation if applicable

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Statute of Limitations by State

Under most states’ discovery rules, the limitations period begins when you knew or should have known of the injury — typically the date of your NAION diagnosis.

State-by-state reference (consult an attorney for your specific situation):

State	Personal Injury SOL	Discovery Rule
California	2 years	Yes
Texas	2 years	Limited
New York	3 years	Yes
Florida	2 years	Yes
Illinois	2 years	Yes
Pennsylvania	2 years	Yes
Georgia	2 years	Yes
New Jersey	2 years	Yes
Ohio	2 years	Yes
Washington	3 years	Yes

In practice: if you were diagnosed with NAION in 2023 and live in a 2-year SOL state, the clock may be running out. Act without delay.

MDL filing does not automatically preserve SOL — your attorney must file a complaint (Short Form Complaint) to toll the limitations period.

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A Practical Patient Scenario

The patient: A 62-year-old type 2 diabetic man in Virginia who started Ozempic in early 2023 for diabetes management. His A1c was well-controlled; his blood pressure was managed with medication.

What happened: In late 2023, he woke to find the upper half of his left visual field missing. An ophthalmology appointment confirmed NAION. His cup-to-disc ratio on the affected eye was borderline but not dramatically small.

His legal considerations:

• Diabetes is a known NAION risk factor — this will be the centerpiece of Novo Nordisk’s defense
• But his treating ophthalmologist noted the presentation was atypical for uncomplicated diabetic NAION
• The short interval between Ozempic initiation and symptom onset (approximately 10 months) supports a temporal link
• Virginia has a 2-year SOL for personal injury; diagnosed late 2023 means the window is closing
• He should consult a mass tort attorney immediately and obtain all pharmacy and ophthalmology records

This scenario illustrates why pre-existing risk factors complicate but rarely eliminate GLP-1 NAION claims. The litigation will turn on expert testimony about whether, given the specific patient’s baseline, the drug exposure was a contributing cause.

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How MDL 3163 Will Proceed

MDL litigation follows a predictable structure. Here is what to expect:

1. Initial case management orders (CMOs): Judge Marston will establish procedural deadlines, PSC composition, discovery protocols, and short-form complaint procedures.

2. Plaintiffs’ Steering Committee (PSC) formation: Leading plaintiff firms will be appointed to coordinate discovery from Novo Nordisk and Eli Lilly.

3. Fact discovery: Attorneys will subpoena internal communications, clinical trial data, FAERS reports, and any internal safety analyses related to NAION.

4. Expert discovery and Daubert briefing: Both sides will retain causation experts. Plaintiffs will need to survive Daubert motions challenging the reliability of their NAION-GLP-1 causation opinions.

5. Bellwether trials: A small number of representative cases (strong and weak) will be tried to juries. Verdicts help set settlement values.

6. Global settlement or continued litigation: Based on bellwether outcomes, parties negotiate a settlement fund, or cases proceed to individual trial.

MDL 3163 is early-stage. The full process may take 3–6 years. Timing is not a reason to delay filing — statute of limitations deadlines are.

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Distinguishing MDL 3163 from MDL 3094

This distinction matters practically.

Feature	MDL 3094	MDL 3163
Injury type	Gastroparesis, ileus, bowel obstruction	NAION — vision loss
Court	E.D. La. (Eastern District of Louisiana)	E.D. Pa. (Eastern District of Pennsylvania)
Presiding judge	Different judge	Hon. Karen S. Marston
Defendants	Novo Nordisk, Eli Lilly, others	Novo Nordisk, Eli Lilly
Eligible injury	GI tract damage from GLP-1 use	Optic nerve ischemia from GLP-1 use

If you have both conditions, you may be eligible for claims in both MDLs. Your attorney would file separate complaints in each.

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What to Do Right Now

1. Collect all prescription records. Contact your prescribing physician and pharmacy for a complete list of GLP-1 prescriptions, doses, and dates.

2. Request your ophthalmology records. Obtain the full record from every eye care provider you have seen, including the NAION diagnosis documentation.

3. Build a timeline. Write down: drug start date, any dose changes, date of first symptom, date of diagnosis.

4. Document functional impact. Note every way the vision loss has changed your life: inability to drive, work changes, loss of reading ability, emotional impact.

5. Contact a mass tort attorney now. Statute of limitations clocks are running. Initial consultations are free. Filing a Short Form Complaint in the MDL preserves your rights.

6. Do not stop monitoring your other eye. NAION patients have meaningfully elevated risk of fellow-eye involvement. Annual ophthalmology follow-up is critical.

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Related Mass Tort and Injury Litigation

• JUUL E-Cigarette Teen Addiction Lawsuit MDL 2913 2026
• 23andMe Data Breach Class Action Lawsuit 2026
• AT&T Data Breach Lawsuit MDL 3114 2026
• Hawaii Maui Wildfire Lawsuit 2026
• Exactech Knee Hip Recall Lawsuit MDL 3044 2026

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This article is for informational purposes only and does not constitute legal advice. Consult a qualified attorney for advice specific to your situation. Laws vary by state. Information current as of May 2026; the MDL is active and evolving.