User blog comment:Damac1214/Black Ops 2 Uprising DLC Trailer Released + Double XP on April 12th to April 15th/@comment-3038088-20130404192613/@comment-142.162.22.42-20130405105904

This may sound stupid, but Richtofen can probably change the eye color of the zombies whenever he wants. Maybe in the next DLC the zombies eyes will be purple. But until the DLC comes out the anwser to this question will be "We dont know".