Why Do Hazel Eyes Change Color?

Blue eyes are blue to lack of melanin, brown eyes are brown due to a lot of melanin and hazel or green eyes have melanin levels in between, and, as such, can appear to take on different hues based on how they blend with the colors people wear, the color of their hair

Hazel eyes play a delicate game of limbo between brown and blue, having less pigment than brown and more than blue.