I have blue green eyes, and around each pupil there is light brown. In addition, the upper corner of my right iris is dark brown. I was not born with this difference in color; it was noticed around age 2-3. My mother was told it was a birthmark (iris nevi), however, in my research of this, I came across sectoral heterochromia as a possible cause. No others in my family have this, that I know of, so I can t imagine it is hereditary. Neither the color around my pupils nor the section in my right eye has changed in size or color, nor has it impeded my vision or caused any other issues over the years. I am curious as to to how tell which condition it could be since it sounds like it could be both?