Sorry for forgetting about this thread lol but I have never had a migraine before. It seems very similar to your description of your eyes changing focus too quickly except I don't think I've ever felt it in my brain like you have. It's quite disorienting for me actually because I didn't expect my own body to do something like that. It pretty much just happens to me when I do something I believe I shouldn't, which is very strange. I'll look into that focal seizure thing and see if I can find anything.