As you look closely in the mirror trying to disprove this, physics explains how this is possible. Your eyes appear blue in the same way that the sky appears blue- scattered light. The iris, which is responsible for eye color, has three layers. Each layer has different color pigments such as yellow or brown which, when combined, make hazel and brown eyes.
But blue and grey eyes have a brown pigment in one small layer of the eye and as light bounces off of the iris, creates a blue color due to its short wavelengths!