Board Thread:Legitimate Canon Questions/@comment-4083360-20140108131256/@comment-4091815-20140108134944

The answer is no based on all we've seen. Peter Hale and all the members of The Alpha Pack killed people and still retained the red eyes.

If, more specifically, you're asking if the taking of an innocent life would effect Alpha eye color - we don't know since no "innocents" have been killed by an Alpha on screen to date. Peter killed his nurse but she wasn't innocent since she helped him kill Laura and the rest.