,,Die Augen sind die Seelefenster"

That's a nifty little german phrase, its english-approximate being "Eyes are the window of the soul." And as it turns out, it may just be true. Anthropologists have uncovered some interesting findings about our eyes and how others percieve us.
Of course, how we "read" people determines an essential aspect of choosing your future partner. As it turns out, the iris of the eye has two physical traits that have been linked to personality differences. The number of "crypts" or pits in the iris signal how likely you are to be warm, tender and trusting. And the number of "furrows," or curving lines along the outer edge of the iris, signal the degree to which you are likely to be neurotic, impulsive and willing to assuage your cravings. In both cases, the more crypts or furrows, the more likely you are to be, respectively, tender hearted or spontaneous. These traits develop in the womb. In short, we have evolved a remarkable and subtle biological strategy to signal who we are.
In an evolutionary sense, this is a very efficient strategy of helping determine potential mates -- afterall, anything that saves time (instead of spending several months or even years trying to figure out if someone is really loyal, or just manipulative) is inheriently energy saving. Thus, you save resources; and have a better chance of survival. In a wider sense; finding loyal mates that will stick around and support offspring, and yourself, is in terms of survival: excellent.
This also leads to some interesting aspects of culture and history. Nearly every culture throughout history has accentuated the eyes to some extent. Ancient near-eastern peoples would use makeups. For Egyptians specifically, both men and women would use mascara to draw attention to the eyes (plus, the darker paints around the eyes reduce sun-glare -- similar to the way modern day football players stripe their faces before a game.) Not to mention cultural rules on maintaining eye-contact.

Source: http://www.helenfisher.typepad.com/