To avoid red eye it helps to know the cause. The effect is actually the light (usually from a flash built onto your camera) bouncing off your subjects retina and back to the camera. It’s worse when your pupils are dilated because then more light is let into your eye and thus more light will bounce off your retina. Cameras have built in features to make the pupils smaller such as firing a few flashes or other light before taking the actual picture. The cameras built in features for reducing red eye are not always 100% successful, so beyond that here are a few other options for avoiding red-eye in your photos.
Use an External Flash
Have the light come from a different angle rather than directly from the camera. This will severely limit the high amount of light hitting the retina and flashing directly back at the camera.
Light the Environment
The light bouncing back from your retina wont be as extreme if you have a relatively well lit environment. So if possible turn on some lights.
Remove Red Eye by Photo Editing
If you don’t have the correct lighting to avoid red eye as the shot is being taken there are luckily lots of options out there to edit out the red color. The eye is very complex and so I’ve never seen software doing this flawlessly, but it’s a convenient last resort.
To remove red eyes in Photoshop there is a tool for this specific task. Once you select the tool you just have to drag it across an eye to remove or cover the red eye. Apply to tool to each eye individually. The result can be seen above and isn’t that impressive, but it’s an improvement for family photos. If you’re looking to have a professional looking photograph then plan on taking the photograph in a way that won’t have red eye using the 3 methods above.