A girl suspects something is wrong. Someone tells her that her iris is discolored and that it means that she had a twin at birth. It came out about a year or so. Horror or thriller. Can't remember the name.

Sounds like The Unborn
http://www.youtube.com/watch?v=sc3Cba0qOco

Sounds like The Unborn
YouTube - ‪The Unborn [Trailer 2] [HD] 2009‬‎ (http://www.youtube.com/watch?v=sc3Cba0qOco)

Wow! Thank you so much. That was it. I love this website. :)

Good. :) I can only answer a movie question once in a great while, but it's fun when I can.