The color of the iris is based on the amount of pigment, or melanin, present throughout the different layers of the iris. The more pigment present, the darker the eyes. The less pigment present, the lighter the eyes. ... one blue iris and one brown iris).

Why are iris different colors?

The colour of the iris is determined by the amount of melanin pigments, the way the melanin is distributed in the eye and the ratio of eumelanin to pheomelanin. Eye colours have been divided into nine categories and as many as 16 genes have been associated with eye colour inheritance.

How do irises get their color?

What gives eyes their color. The iris color is determined by the amount of melanin pigmentation. The more pigment there is, the darker the iris will be. Blue, gray, and green eyes are lighter because there is less melanin inside the iris.