Variations in eye color range from light blue to dark brown and are inherited. Eye color is chiefly determined by the amount and distribution of melanin within the irises. If melanin is present only in the epithelial cells that cover the posterior surface of the iris, the iris appears blue. When this condition exists together with denser-than-usual tissue within the body of the iris, the eye color looks gray. When melanin is present within the body of the iris, as well as the epithelial covering, the iris appears brown.