If you've been shopping around for circle lenses, you may have noticed that some have a prominent black line around them while others don't. This is the limbal ring. If you go and run for the mirror right now, you may or may not see your own. This ring is thought to be an indicator of youthfulness as they appear thickest near your early twenties, and fade from there.
Researchers at the University of California at Irvine have even gone so far as to do a study where they showed volunteers eighty pairs of male and female faces. The faces were
completely identical except for the darkness and size of the limbal
ring. When asked who they thought was more attractive, the faces with the
larger limbal rings invariably won out.
We already know that a bright white sclera (whites of the eyes) is an indicator of good health, and we generally use this, as well as facial symmetry, colour and shape of teeth, hair health and many other minor cues to determine attractiveness. The darker limbal ring may only be providing the appearance of brighter eyes by providing contrast, but if we're willing to whiten our teeth, use wrinkle creams, and adjust the appearance of our features with make up, it's no wonder people are rushing to get circle lenses.
This doesn't only affect men's perception of women. According to the study, men are judged equally by women seeking youthfulness, symmetry and health, so stock up on your circle lenses, boys!
Source: Evolutionary Psychology – ISSN 1474-7049 – Volume 9(2). 2011