You've seen the horrendous demon-eye effect that occurs when light from the camera's flash bounces off the eye of a person or pet. Many wonderful photographs are ruined by this. In technical jargon, this is called red-eye and is caused when the pupil of your subject's eye is wide open and the light from the camera's flash reflects off the subject's retina. In people, the eyes end up red; in pets, the eyes are often green.
Many photo editing programs include a red-eye correction filter, but your photograph's subject may not appear to be normal. These filters also do not work on the green effect produced in a pets eyes. Photo stores also sell pens that are used to correct the red-eye in photographs, but again they are not always natural-looking and are not effective on the green. It is best to prevent the demon-eye effect from the start. More... / Hide...
Most digital camera includes a red-eye reduction feature. This feature can be switdhed off or on. It is best left on in all situation other than direct sunlight. The red-eye reducing feature flashes a short burst of light at your subject just before you snap the photo. This burst of light causes the subjects pupil to close and makes it less likely for the camera's flash to reflect off the retina. The chances of getting red-eyed photographs is hence reduced.
It also helps to direct your camera's flash away from your subject's eyes. Bounce the flash off a nearby wall or other object to soften its effect and reduce the chances of this unwanted malady. Between bouncing the flash and using your digital cameras red-eye reduction feature, your little angel, whether human or animal, will have eyes that do not glow.