I have experienced NAION, a mini stroke, to both eyes, as well. Have you seen a neuro_ophthalmologist to confirm this diagnosis? I haven't started Entyvio yet, but my GI doc said that that is my next step and I need to do it now, but I've been extremely reluctant to try any of the biologics for fear of losing more sight. UC and Crohn's, as you know, cause inflammation throughout the body, and NAION is caused from swelling, causing blood flow to the optic nerve to be compromised, killing off of damaging it permanently. There is no cure, although they're working on it. I questioned my doc about a connection between the two diseases and was told no, but I can't see how there couldn't be. Be very vigilant about seeing your eye doctor to have your ocular pressure checked. There is a 15-20% chance of it happening to your other eye.