The Colour-Coded for Your Convenience trope as used in popular culture. Vision is the one sense we humans rely on the most. We usually identify things by . The science behind Green Eyes: Green eyes are the least common eye color. In order to have green eyes a person must have a yellow colored stroma. The yellowish stroma appears green due to Rayliegh scattering, the principle that makes the sky blue, blue plus yellow equals green. I love the color and the ease of application. I have blue eyes and blond hair. The blue gray (actually looks more gray with just a hint of blue -- which is great, doesn't look too artificial) is perfect for me.