Your retina and pupil is being squeezed so much that it is contracting all the Colors（色） in the area and transfers it into your eye while あなた are rubbing them. This is what I found while searching it.
posted １年以上前
I was told something along that line when I got this big floater - when I closed または moved my eye suddenly, I would get this burst of colours. The doctor explained it as being caused によって the shrinking of the eyeball. The same effect could also happen if あなた have something seriously wrong with the eye.
