Please do come along and leave me beautiful sexy comments, I love them, they are always interesting...
Here is an excerpt:
Iris colour is a highly complex phenomenon consisting of the combined effects of texture, pigmentation, density within the iris stroma, and the scattering of light in the stroma.
Only Melanin, a yellowish-brown to dark brown pigment exists in the stroma.
This pigment lies in a thin but very opaque layer across the back of the iris.
Neither blue nor green pigments are ever present in the iris!
So it all depends on the lighting conditions and all the other components beside the stroma and how lights reflects/scatters and is absorbed on them - Especially if you have lighter-colored eyes, since there is no melanin pigments to enter this equation.
Now that we know this, we can understand better why some babies, usually Caucasian ones, are born blue-eyed: