1. A method implemented at least in part by a computer system, the method for correcting color defects in a pupil represented in a digital image, and the method comprising the steps of: identifying an expected pupil-location within the digital image; determining that all or substantially all of the pixels within a particular region in which the expected pupil-location resides have a white or a substantially white color; identifying a presumed pupil region; and inserting into the presumed pupil region an image of a pupil configured to fit the presumed pupil region when all or substantially all of the pixels within a particular region in which the expected pupil-location resides have a white or a substantially white color.