Human/Animal Eyes

[LilKim]

I've been having a hard time finding the answer to this. Why do animal's eyes (most of them--think dogs and cats) show gold/green under a camera flash, and ours show red? Does it have something to do with the cones?

Demon Zoe


Happy Zoe

[KStraker]

At the back of their eyes dogs have a mirror-like layer of cells called the tapetum lucidum. The job of the tapetum lucidum is to improve your dogs vision in dim light, and it does this by reflecting light back to the retina.
(hijacked from the internet)

[mlm]

Side note...

I was pretesting a patient a few years ago, and when I showed him his retinal photos, he said "Wow, human eyes are so boring looking!" I gave him a funny look and he then explained that he was a veterinarian. :hammer:

[Night Train]

Is it also true that dogs only see in black and white? If so, Why is this?

[obxeyeguy]

...

[LilKim]

Ahhh, found some more interesting answers to my original question.

Eyeshine is a visible effect of the tapetum lucidum. When a light is shone into the eye of an animal having a tapetum lucidum, the pupil appears to glow. Eyeshine occurs in a wide variety of colors including white, blue, green, yellow, pink and red.

The human eye has no tapetum lucidum, hence no eyeshine. However, in humans and animals two effects can occur that may resemble eyeshine: leukoria (white shine, indicative of abnormalities including cataracts, cancers, and other problems), and red-shine (apparent only in flash photography).

Cats and dogs with blue eyes, may display both eyeshine and red-eye effect. Both species have a tapetum lucidum, so their pupils may display eyeshine. In flash color photographs, however, individuals with blue eyes may also display a distinctive red eyeshine.

Apart from its eyeshine, the tapetum luminum itself has a color. It is often described as iridescent. In tigers it is greenish. In dogs it may be whitish with a blue periphery.

Red-eye is a common problem with flash photography of humans because, with no tapetum lucidum layer to block it, the light reaches the blood-rich region at the back of the eye and causes a brilliant red image of it to be focused back through the lens of the eye, giving even the nicest people red, glowing, demonic eyes in flash photographs.

[GAgal]

Is it also true that dogs only see in black and white? If so, Why is this?

Dogs can see certain colors, like yellow, violet and blue, they just can't see shades of red and green. Dogs only have color receptors for yellow and blue wavelengths. Their eyes are developed to detect movements.