I have auras with headache and some without. I get the zigzags, the flickering (old movie reel), partial loss of vision (bottom part of my visual field went grey like when a tv doesn't get a signal "snowy") and double vision. It's been going on for almost 5 years now. All of the above symptoms were without headache. You're not alone. Did you seek medical advice? If not you should, because it could be something else. When it happens to me, my optometrist wants to see me to check my eyes to make sure that it's not anything serious. PS check "ocular migraine" on the internet for more info.