(/)
Illustrated by: Erika Onodera
It is due to an abnormality called heterochromia. It can either be genetically inherited or acquired through disease or injury. There are two types: the sectoral (two colors in the same eye) and the complete (one eye of each color), and it is even possible to have both types at the same time. All sorts of combinations are possible (blue and green, brown and blue, etc.). The decisive factor is the same as for those who have the same two eyes: the amount of melanin in the iris of the eyeball. This amount is determined by a number of different genes (i.e. Mendel’s First Law does not apply here), such as OCA2 and EYCL3, and these are affected when a person has genetic heterochromia. The phenomenon occurs in less than 1% of the world’s population (and in some dogs and cats). It is harmless, but it can also be caused by some serious diseases like neurofibromatosis.
READ MORE
– Is it possible to sleep with your eyes open?
– Why do Orientals have open eyes?
WINDOW’S SOUL
Learn how color is determined and learn about possible variations
Brown -Too much melanin and too many melanosomes
Green -Medium amounts of melanin and melanosomes
Blue – Little melanin and few melanosomes
TYPES OF HETEROCROMY
1) Segmented sector
2) Central sector
3) Complete
4) Complete sector
QUESTION Kaique Rossoni, Colatina, ES
SOURCE Article Genetics of Eye Color, Hudson Alpha Institute for Biotechnology; websites Dráuzio Varela, Saúde Visual and Medicine Net
CONSULTANCY Keila Monteiro de Carvalho, director of the Brazilian Council of Ophthalmology