Why are our Eyes Coloured

There is so much more to the colour of a person’s eyes than just the colour. It can show where their ancestors may have been from, what eye colour eyes their parents may have had and how healthy a person may be.

The most common eye colour is brown, then blue/grey and lastly green eye colour. However, the variance between these three colours is never ending. Eye colour is determined through the genetics of your parents, so like any other part of your body, is affected by the numerous potential combinations proposed by mixing to genomes. General rules are observed; brown eye colour has a dominant gene, whereas blue and green are recessive, however, outcomes are not always predictable; parents with brown eye colour and could still potentially produce a child with blue eyes.

The coloured part of the eye is called the Iris. Its function is to regulate the amount of light entering the eye through the pupil. It is believed that the role of pigment in the iris is to protect it from UV rays, much like the role of pigment (melanin) in the skin. This is the body’s natural version of wearing some funky Ray Ban or Oakley sunglasses, just slightly less effective. So, following this theory, brown eyes have the most protection from UV-rays, and blue has the least. This theory is reinforced when one looks at the distribution of eye-colour throughout Europe. People living further north and therefore less exposed to UV-rays have blue eyes. In sunnier climbs the dominate eye colour is brown.

Within the basic brown, blue and green eye colours there is a rainbow of outcomes, from hazel, chestnut, amber, gunmetal grey to electric blue.  These colours not only describe a colour but can affect an individual’s personality, for example Elizabeth Taylor, who’s famous for her deep blue eyes.

The iris can also provide a great deal of information about a person’s pathological history and it is easy to track any changes in it, for examples spots, flecks or boarders, or even the rare heterochromia where eyes appear different colours. Such knowledge can help developments in medication as well as help spot any illness that a person could be suffering from, so keep and eye out, and look into other people’s!

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