Like most human traits, blue eyes are determined by genes, and no two people have exactly the same hue. It works a lot like ...

Any animal’s eye color is determined by its levels of two melanin pigments: eumelanin, which makes brown-black, and ...

gray, hazel, green, brown, near-black—but scientists believe that they’re all slightly different manifestations of blue eyes or brown eyes. “It may seem like green is rare,” says Dr ...