Hi, I've gotten several of them over the years. Starting when I was 14. It can be very scary. Mine are a circle area that starts in one corner of my eye and slowly moves, in to my vision, then out to the other corner of my eye when it then disappears. It's got wiggly shimmering lines in it too. One time I got it while driving, I had to pull over and sit there till it was gone. It just competely messes up your vision!
I've seen my eye doctor about it, and he confirmed what it was, and told me even though they are awful to have, they don't cause any damage if that's all it is!
Diagnosed with mild Crohn's Disease 2/06 after sever GI bleed. Has been suffering since 1998. History of rectal fistula and gallbladder removal. Currently taking Asacol and Questran.