What are these strange patterns behind my eyes?

This is not a medical problem; I’ve had this since I was a kid…so all my life really… I notice it when I’m in the shower and I’m closing my eyes to wash my face…

It might be something to do with the rubbing action of washing my eyes – come to think of it… but with my eyes closed I get these strange kaleidoscope patterns behind my eyelids… I see patterns of different colours…. moving and forever changing…

I guess it’s a little bit like this but lots of different ones, more intricate and moving a lot faster… on a completely black background and the colours are more solid and bold….

I just wondered whether anyone else gets this and if you know what it is?