An anonymous reader quotes a report from NBC News: The Food and Drug Administration said Monday that GLP-1 drugmakers must add a warning label about a rare eye condition that can cause sudden blindness . The condition, called nonarteritic anterior ischemic optic neuropathy, or NAION, affects the optic nerve, which carries signals from the eye to the brain. When blood flow to the nerve is reduced or blocked, it can cause sudden vision loss. The condition is permanent with no known treatment. The FDA said "there is a potential increased risk of rare NAION" in people taking GLP-1 drugs. The agency's requirement applies to all GLP-1s, including Novo Nordisk's Ozempic and Wegovy and Eli Lilly's Mounjaro and Zepbound, as well as several older GLP-1 diabetes medications.…