Ozempic Vision Loss Lawsuit Heads to Science Day on June 2: What It Means for the Case
The federal Ozempic vision loss lawsuit reaches a critical milestone on June 2, 2026, when both sides present the science behind claims that GLP-1 drugs cause sudden blindness. What Science Day means and why it matters.
By 411 Press Newsroom4 min read
On June 2, 2026, the federal Ozempic vision loss lawsuit hits its first major milestone.
Judge Karen Spencer Marston has scheduled a Science Day hearing in the Eastern District of Pennsylvania for MDL No. 3163 — the multidistrict litigation alleging that Ozempic, Wegovy, and other GLP-1 receptor agonist drugs cause NAION, a form of sudden, permanent vision loss.
Each side gets 2.5 hours. Plaintiffs will present evidence that semaglutide and related drugs cause NAION. Novo Nordisk and Eli Lilly will argue they do not. The judge watches, asks questions, and learns the science that will underpin every decision in this litigation going forward.
This is not a trial. No verdict comes out of it. But Science Day may be the most important day this case has had so far.
What Is Science Day?
Science Day is an educational hearing. It exists to bring the judge up to speed on the medical and scientific issues before formal expert discovery begins. Think of it as a seminar, not a courtroom battle.
In her March 16 order, Judge Marston directed each side to present "non-adversarial explanations of the science behind the claims." That means no cross-examination, no objections, no legal arguments. Just science.
Both sides will present expert witnesses — ophthalmologists, pharmacologists, epidemiologists — who will explain what NAION is, how GLP-1 drugs work, and whether the evidence supports a causal link between the two.
What Is NAION?
Non-arteritic anterior ischemic optic neuropathy is a condition where blood flow to the optic nerve is suddenly disrupted. It causes immediate, painless vision loss in one eye. In many cases, the damage is permanent.
NAION is sometimes called an "eye stroke." It is the most common cause of sudden optic nerve damage in adults over 50, but it can occur at any age.
The plaintiffs in MDL 3163 allege that GLP-1 drugs — specifically semaglutide (sold as Ozempic and Wegovy) and tirzepatide (sold as Mounjaro and Zepbound) — significantly increase the risk of developing NAION.
The Evidence So Far
Multiple published studies have found an association between GLP-1 drug use and elevated NAION risk:
- A 2024 JAMA Ophthalmology study found semaglutide users with Type 2 diabetes had more than double the risk of developing NAION. For weight-loss patients without diabetes, the risk was approximately seven times higher.
- A Veterans Affairs study found a 35% higher NAION rate among GLP-1 users — 39 per 10,000 patients compared to 29 per 10,000 in non-users.
- A separate longitudinal analysis showed semaglutide patients had an 8.9% NAION incidence at 36 months, compared to 1.8% in patients not taking GLP-1 drugs.
- The World Health Organization issued a warning in June 2025 regarding a rare NAION risk associated with semaglutide.
The defendants will argue that these studies show correlation, not causation — and that NAION risk factors (diabetes, obesity, hypertension) overlap heavily with the patient population taking GLP-1 drugs.
That argument is what Science Day will test.
Where the Litigation Stands
The numbers as of May 2026:
| NAION/Vision Loss Cases (MDL 3163) | 86 pending |
| GI Injury Cases (MDL 3094) | 3,636 pending |
| Total GLP-1 Cases | 3,722+ across both MDLs |
| Judge | Karen Spencer Marston, E.D. Pa. |
| Defendants | Novo Nordisk (Ozempic, Wegovy), Eli Lilly (Mounjaro, Zepbound) |
MDL 3163 was created in December 2025 by the Judicial Panel on Multidistrict Litigation. It is separate from MDL 3094, which covers gastrointestinal injuries like gastroparesis and bowel obstruction. Both are overseen by Judge Marston.
No bellwether trials have been scheduled. Case-specific discovery has not begun. Settlement is likely years away.
What Happens After Science Day
Science Day does not produce a ruling. But it shapes everything that follows — expert discovery, Daubert challenges (motions to exclude expert testimony), and eventually which cases proceed to bellwether trials.
If the plaintiffs' science holds up, the litigation moves forward with momentum. If the defendants successfully challenge it, the case slows down. For the 86 plaintiffs currently in MDL 3163, June 2 is the first real test of whether their claims will survive.
What You Should Know
If you or someone you know took Ozempic, Wegovy, Mounjaro, or another GLP-1 drug and experienced sudden vision loss, the statute of limitations for filing a claim varies by state. Most states allow two to three years from the date of injury or diagnosis.
Read the full 411 Press Ozempic lawsuit guide for plaintiff class, case status, and filing-deadline context.
Do not stop taking a prescribed medication without consulting your doctor. If you experience sudden, painless vision loss in one eye while taking a GLP-1 drug, seek emergency medical attention immediately.
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