Ask an Eye Doctor and Get an Answer ASAP
This is Dr. David
if you had excessive fluid or mucus in your eyes when you woke up which is very common, the light hitting the tearing or fluid in the eye can refract light and cause a prism or rainbow effect to your vision for short period of time
once you wash up and wash your face and get the fluid and mucus out of your eyes, it should go away.
I would not worry about this effect too much.
let me know if you have other questions.