Today I presented my Red-Eye presentation. I took some notes from the link below which is all about Red-Eye.
Here are the notes:
Minimizing Red-Eye in Your Photos

• Red-Eye is caused by the light from the flash reflected from a photographed persons blood vessels in their eyes back to the camera lens, which causes the person to have red eyes in the photograph.

• Camera manufacturers have made a feature called "Preflash"
• They fire a flash to force the persons iris to close which prevents the blood vessels from reflecting to your camera.
• Then the actual flash is fired and the photo taken.
• After the preflash has been fired, it causes the person to squint their eyes, so when the actual photo is taken, they will have their eyes closed.
  
• Preflash does not completely prevent red-eye.

• A better solution is something called "External Flash".
• It fires the flash from a different angle.
• Which prevents the light reflected from the persons eye from being captured by the camera.
• You will need to buy a DSLR camera with a "hot shoe" where you can attach the external flash.
• External Flash is sold separately.
  

Hot Shoe www.conraderb.com
External Flash www.karbosguide.com

How External Flash prevents Red-Eye
http://www.digital-slr-guide.com/digital-slr-flash.html