percentage of the world that has brown eyes
Eye color Dark brown eyes are dominant in humans[58] and in many parts of the world, it is nearly the only iris color present.[59] Dark pigment of brown eyes is common in Europe, South Europe, East Asia, Southeast Asia, Central Asia, South Asia, West Asia, Oceania, Africa, Americas, etc. as well as parts of Eastern Europe and Southern Europe.[17] The majority of people in the world overall have brown eyes to dark brown eyes.
Sclera The sclera,[help 1] also known as the white of the eye, is the opaque, fibrous, protective, outer layer of the human eye containing mainly collagen and some elastic fiber.[2] In humans, the whole sclera is white, contrasting with the coloured iris, but in other mammals the visible part of the sclera matches the colour of the iris, so the white part does not normally show. In the development of the embryo, the sclera is derived from the neural crest.[3] In children, it is thinner and shows some of the underlying pigment, appearing slightly blue. In the elderly, fatty deposits on the sclera can make it appear slightly yellow. Many people with dark skin have naturally darkened sclerae, the result of melanin pigmentation.