If an animal has cataracs it will cause them to have different eye color when light hits them, so don't count on eye color for animal identification with a light at night.
You can shine family pets at night and see this at times, but in my opinion nothing is safer or better than seeing the whole animal before taking a shot. Not saying that your implying shooting by eye color at night by any means. Just that eye color can change in animals with eye problems or disease.