actually grey eyes may mean you are blind/half blind
like me
ACTUALLY, grey eyes are caused by a dark epithelium at the back of the iris and a relatively clear stroma at the front of the iris. Unlike blue eyes, there are relatively large deposits of collagen in the stroma, so that the light that is reflected from the epithelium undergoes Mie scattering (which is not strongly frequency-dependent) rather than Rayleigh scattering (in which shorter wavelengths of light are scattered more).
:P
Anyways. To those who don't have brown eyes: you're a dying species. You may be the last of your kind. Sooner or later, the human race will only have brown eyes.