system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: I was born with blue eyes, when I was young my eyes would change colors from Blue to green. Now my eyes are more a greenish hazel. What caused this?

Like what causes eye color it change a lot, and then eventually just pick a color and stay like that? Does it have to do with my parents gene pool fighting for supremacy?
gpt
Let me explain how eye color work first: Human body does not produce blue or green pigment, it can only produce brown pigment. People with brown eyes have a lot of pigment in their iris. People with blue eyes have very few. Blue eyes appear blue because lights refract in the iris in the same manner as the sky or the ocean. Air and sea water are both clear, but because only blue lights are passed through so the sky and the ocean appear blue to us. Green eyes have a very thin layer of pigment on top of the iris, it's so thin that it's yellow instead of brown. Yellow combined with blue will make green. 

Notice how the sky or the ocean change color under certain weather conditions or lights? Blue eyes sometimes change color the same way. When you get older more pigments may appear, like many blond children end up with much darker hair as adults, eyes can get more pigments as well.