Is it possible for humans to develop red eyes naturally?

Yellow eyes are easy - caused by jaundice, a side effect of liver failure, from diseases such as hepatitis or yellow fever.

Violet eyes are very rare, and are caused by a mutation. On the Martin-Schultz scale, they are considered a subset of blue eyes.

Red eyes are also rare, and occur in people with severe ocular albinism. This is due to extremely low levels of melanin in the iris allowing the underlying colour of the blood vessels to show through. ( http://upload.wikimedia.org/wikipedia/commons/f/f7... )

Normally the inside of your eyes look black (the pupil of the eye being the window to the interior), but red-eye essentially reveals that given enough light, they're balls of transparent jelly with red walls. Here's why. A camera flash happens faster than the iris of the eye can close the pupil (you can see the pupil's of people's eyes getting smaller if you happen to be looking at their eyes when they walk from a dark room into a sunny outdoors). The lens of the eye focuses the light from the flash onto the retina at the back of the eyeball, which is red because of all the blood vessels in it. People with blue or grey eyes get worse red-eye because their pupils have less melanin in them (the pigmentation that makes brown eyes brown and moles on your skin dark). Some animals, such as cats, have green- or yellow-eye instead of red. This is because they have a light-reflecting layer behind the retina, to help their night vision. It affects the colour of the reflected light. You can do various things to improve red-eye. You can use a separate flash unit and point the flash at a nearby reflective surface, instead of straight at the subject of the photo, which is what pros usually do. Many modern cameras have a red-eye reduction feature, which sets off a small series of low-power flashes before the main flash, causing the pupil to contract in advance. You can ask people not to look at the camera, which is probably a good idea anyway as it tends to make them look better. There are other things you can do, like processing the film in certain ways, or using software to digitally process out the red-eye. Or, of course, you can just not use flash.

Yellow eyes is easy - liver Diseases will cause the white of the eyes to turn yellow.

(like Hepatitis B, the liver can't get rid of toxins).

Pink eyes - albinos have white hair, pale skine, and pink/ red eyes, they are born that way.

changing color - most babies who have blue eyes - blue changes until they are about 6 (mostly to green).

- mine did

Guinness Book of Records - I read about a boy who had a first unknowen mutation that make him see in the dark ( and his eyes turn bright green when catching light, like a lion in the savannah).

or was is it "Repley's believe it or not"?