Hi Alina!
I don't know if I have understood you right -do you mean in this reality? not while astral traveling, dreaming...?

About the blue to green and back again I found what could be an answer
"As in blue eyes, there is no green pigment. Instead, because of the lack of melanin in the iris, more light scatters out, which make the eyes appear green. Changes in light make lighter eyes look like they are changing colors like a chameleon." (Source Lunadna.com)

I have had experiences while dreaming that felt like visitations dreams, something real to it. 2 times about 2 different people having changed their physical looks. With 1 of them it is in real life real important to look fresh, to have the hair cut, clean clothes, but in the state I was in I saw this person look the opposite. The way we figured it to be was the theory that it is how this person feel like on the inside that make the physical appearance in my state.