Observational Study Description H6D-MC-LVHQ(b) A Prospective Case-Crossover Study to Evaluate the Possible Association Between the Use of PDE5 inhibitors and the Risk of Acute Nonarteritic Anterior Ischaemic Optic Neuropathy (NAION) First published 13/04/2017 Last updated 30/03/2024 EU PAS number:EUPAS13266 Study Finalised