For a bout a year now I have seen a small spinning sphere whenever I close my eyes. When I consciously try to focus on it, it becomes very clear and super-active. In the past few months I have been able to see it even when my eyes are open if I stare into the near distance and glaze my eyes, particularly if it is a little dark. It does not distort my vision and my eyes are great otherwise.
It’s not really spinning. I would describe it as more of an undulating or flashing movement. Imagine a plasma ball. Put your finger in the centre of the ball and imagine the electrical streaks shooting towards and away from it. Sometimes it looks a little like this. At other times they seem like straight rods or spokes alternating in brightness as they circle the centre.