I'm thoroughly enjoying this! I've never met anyone with this before either! It's bizarre. It's like describing to someone how it feels to have your brain, fully conscious, slowly disconnect itself from all its inputs and then slowly figure itself out again. I get that black hole too! Although I'd describe it as more of a missing section of vision. I wouldn't know what color it is. I can't tell. It's like my brain is just making up whatever goes there and none of it could even be remotely real. The only thing about that hole that seems to be consistent is the edges shimmer, pulse, and almost seem brighter than they should be. It's always the first thing to show up for me, and it always initially looks like that spot that shows up when you look at a bright light and then look away, but instead of fading, it just grows and grows.