<human>: I went to a physical check up and the doctor there told me himself that it is way beyond anything he has ever heard of and he could not even begin to explain or help me with this problem.  Anyway, here it is.  For some reason, randomly every 2-3 weeks, I'll be fine one second, then bam, colors start getting brighter and weird shit happens.  It first starts with a little nerds rope looking squiggle somewhere in my peripheral vision or something.  It is constantly moving like some sort of rainbow watercolor gas or something.  It starts growing and growing and growing until at least half of my field of vision is blocked entirely by this chaotic rainbow....  thing.... 

I'm pretty sure it may be neural related or something, because I can close one of my eyes and still see it on the other side, if that makes sense.  After about 10-15 minutes, it goes away.  Physically and mentally, I feel fine, but this visual phenomenon just comes out of nowhere and can be vexing sometimes.  I was taking a test in class a few months ago and this visual stimuli came on in the middle of it and I couldn't even read the questions with one side of my vision.  

I have perfect vision (20/13), am healthy, and I don't see why this is happening.  I'm not sure if it's a danger to my health or not.  Have any of you experienced something like this?

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<bot>: I am seeing rainbows and they are blocking my vision once every 2-3 weeks randomly and I do not know what it could be.