I experience these types of "Reality fluctuations" too. I wouldn't be too concerned though. It's just that when you're trancing out, your consciousness is in an altered state.
So your brain is simply not concentrating as much on translating your vision in a normal way, and just kind of throws its hands up and says, "I take a break!"
So you will see things like the walls start to ripple, objects expand/shrink in size, everything go dark, etc.
I've had this ever since I was a kid, and have asked people about it. Noone seems to have the same thing happen to them that I've talked to (mainly family). Sometimes when I'm tired and kind of sitting there trancing out, my vision will change. It happens often while watching TV. I'll be staring at the TV not paying much attention to it, in an almost trance like state...but with my eyes open of course. After a while my vision will zoom out to an almost fish-eye lens type view. Everything in the room looks like it gets tiny and I get giant. It literally looks like I'm inside toy house and everything is miniaturized. However it doesn't feel as if I can pop out of my body at this point. If I close my eyes during this, I still feel it. I feel that I am either infinitly big or infinitly small. If I shake my head, everything goes back to normal, but I only have to stare a few more seconds for it to kick back in. Does anyone know what this is? I have experienced this feeling once before when trying to project and imagining myself floating above my body, so I wonder if it has something to do with projection. Opinions?