Ask A Scientist General Science Archive

name          Justin
status        educator
grade         K-3
location     RI

Question -   I understand what determines eye color, but  what is the
purpose of having eye color? I mean, does the color of  our eyes have any
effect on vision or color  perception?
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I don't think it has anything to do with vision.  Just like darker  skinned 
races are found in regions where there is more intense sunlight,  and lighter 
skinned races are found in areas away from intense sunlight (the  ease of 
migration has, of course, changed this in modern times), people tend to  have 
darker eyes or lighter eyes in these areas also.  Darker colors tend  to absorb 
light and perhaps the purpose of darker irises is to help absorb some  light 
before it enters through the pupil.  In areas that have  less intense light, it 
may have been an advantage to absorb more  light.  However, this could also be 
due to a random mutation that did not  affect the survival of those with 
lighter eyes.  In other words, if a  random mutation made darker eyes lighter, and 
the light level was low  anyway, it wouldn't matter if you had light eyes.
 
vanhoeck 
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