Thousands of GLP-1 vision loss lawsuits consolidated in federal court

Thousands of lawsuits alleging that popular GLP-1 drugs caused a rare form of sudden vision loss have been consolidated into a single federal proceeding, with the central question of whether the medications can cause the condition now headed for early resolution before a judge. At least 4,000 complaints have been consolidated as multidistrict litigation No. 3163 in the Eastern District of Pennsylvania, according to a report of the proceeding dated September 1, 2026, which listed 216 pending actions. The cases target Novo Nordisk, maker of Ozempic and Wegovy, and Eli Lilly, maker of Mounjaro and Zepbound, over nonarteritic anterior ischemic optic neuropathy, or NAION, a condition sometimes described as an eye stroke that can cause sudden and often permanent vision loss. The U.S. Judicial Panel on Multidistrict Litigation transferred the cases into a single proceeding on December 15, 2025. Judge Karen Spencer Marston has ordered the litigation to address crosscutting issues early, including whether GLP-1 drugs are capable of causing NAION and whether federal law preempts some of the plaintiffs' failure-to-warn claims.