Lui,

Wow, I have the same thing. Back in the 80's when I had no idea what was going on, I went to see a vision surgeon, sorry can't remember what they are called. This is what he told me: The symptoms I described indicate ocular migraines without the pain. He said my eyes were healthy and the cause was internal, meaning the brain.

I still have the problem and it gets worse if I'm too stressed, but mostly I've learned to live with it.
Jamie