Why do our eyes have colour?

So you probably know that the reason we have any color at all in our eyes is because of melanin a pigment in our bodies which makes us have color (e.g. different amounts of melanin in our skins gives us darker or lighter skin) So, much for the same reason we have melanin or pigment in our skin we also have it in our eyes. It's something like protection from UV rays.

If you think about it, most Europeans (note: a predominantly cold region) have light skin (low melanin in skin) & blue or green eyes (again less pigment) whereas areas such as Africa most individuals have dark skin (high melanin in skin) & brown eyes (more pigment). So I think part of our iris color variation, while it can be attributed to mutations in our genetics leading to variations etc., is also because perhaps those traits were most beneficial for our ancestors in the regions they lived in.

Of course, there are a bunch of different proteins & pigments involved in eye color & my answer

is merely a musing theory of mine but I think eye color simply evolved as a noticeable trait as a result of just the nature of optics, like a bi-product of genetics & the mechanics involved.

I mean, if you think about it, eyes are all about perceiving & seeing things, right? Being able to see certain colors at certain distances, etc. Maybe there's a correlation there, we just haven't found it yet.

Check the links in the sources, they'll probably have better insight than me X) I'm just a student.