The fact that our eyes are blue or green is only an optical illusion. There is no dye of such colours in the eyeball. The visual system in every person colours exactly the same pigment – dark brown pigment classified as a melanin. How, then, is there a division into supposed colours? This process takes place between two layers of the iris: anterior stroma and pigmented epithelium. Depending on how much melatonin our eyes contain and how it is distributed on the eyeball, the iris reflects light differently, which gives the impression of a specific colour.
What is intresting, originally every person had brown eyes, says Professor Hans Eiberg from the University of Copenhagen. He and his research team discovered that several thousand years ago this state of affairs changed a genetic mutation affecting the OCA2 gene, which codes the protein P. In the case of blue-eyed melatonin has changed to the same extent. It follows that all people with blue eyes have the same ancestor.
Currently, the most common eye colour among the representatives of the white race is blue – as many as 52% of people have it. Brown-eyed are 27%, and green-eyed are 21%.

Gabrysia Tomaszewska 3aG