If you go to the part of the movie when Dylan and Natalie are trying to break in to the security system (to get back Knox's "stolen technology"), Dylan places her left hand into the scanning gel plate, then her access is granted. When Natalie gets her eyes scanned her access is not granted. Then Natalie moves the contact and tries again. Watch closely....when the camera goes back to the scannings point of view....HER EYES ARE BLUE...WITHOUT THE BROWN CONTACTS! afterwards....when Natalie is in the chamber...her eyes are now blue! Do you think she would have taken off the contacts under these tense circumstances?