system
Given the following post, respond as if you're commenting on Reddit:
human
Is there any evolutionary benefits other than sexual selection in having blue or green eyes instead of brown? 

And other than Caucasian is there any examples known other than those of mixed race with Caucasian that have had the mutation that causes blue or green eyes?
gpt
Like skin tone, lighter eye color is simply a reflection of lower pigmentation (less melanin). As with many genes, if those genes that influence eye color can mutate to less active forms without dicouraging the survival of a given organism, they may continue to mutate to less and less active forms. This means that if higher pigmentation isn't all that advantageous to some animal, lower pigmentation may result. 

There may be a selective factor at work, however: lighter skin tone was favored for north-dwelling human ancestors because it generates more vitamin D (which, closer to the equator, would have been supplied by the abundant sunlight). Because some of the genes that govern skin and eye pigmentation overlap, lighter eye color may have been coincident with lighter skin color.