" red eye reduction "

Why Many cameras have a " red eye reduction " feature?

Why do people
... have red eyes in
flash
photographs?

>We've all see photographs
where the people in the
picture have spooky red eyes.
These are photos taken at
night with a flash. Where do
the red eyes come from?

The red color comes from light that reflects off of the retinas
in our eyes . In many animals, including dogs, cats and deer,
the retina has a special
reflective layer called the tapetum lucidum that acts almost like a mirror at the
backs of their eyes. If you
shine a flashlight or headlights
into their eyes at night, their
eyes shine back with bright,
white light.

Humans don't have this
tapetum lucidum layer in their
retinas.
what you see is the red
color from the blood vessels nourishing the eye