Rainbow in your eye

Have you ever opened your eyes underwater when you were swimming as a child? I use to do it all the time because I never had goggles. When I was done swimming and looked at a light or something with light shining off of it I would see the light but all around it I would see this circular rainbow and wondered how I could see it and no one else could. It was pretty cool until I scared myself and thought that I was going blind.