I think i know what your talking about. I had been noticing these colours for a while and occasionally mentioned to my friends that i was seeing weird colours, they all thought i was crazy until last night when one of my buddies said he knew what i was talking about and it explained it to everyone else who then all realized that they could see them too. Its really strange its like your vision is still completlely normal but you can see like swirling circles of colours and strange patterns and stuff over top of everything and they only seem to happen in the dark.