Many thought the eye color is the part of Iris. That’s not actually right. It depends on melanin (a complex polymer, made from amino acid tyrosine). Scientists proved that a single gene controls eye color although if it is brown or hazel or so on. Moreover, 16 different genes are also involved in this system.
It also determines two factors – 1) Irish pigmentation and 2) Light spreads at the base of the eye. The pigmentation works like a tower. On top of that, you see the light colors and the crystal blue to the green colors. And in the deepest area, it looks like deep brown and dark eyes.
When babies are born, their eyes often appear in blue. That means the melanin is still developing. Within 12 months it starts to produce melanin. It becomes deeper with creating more melanin.