Three cats in night are sitting
      near a tree. They all have got different color of their six eyes.

Color of cat's eyes

Under flash light I have seen
Red and Yellow and Green

Cat eyes in light of a photo flash lamp may be red, yellow and green.

Using a photo flash lamp embedded in a camera we get Red Eye Effect - some persons on a photo have got red pupils of their eyes. It is because the camera sees a reflection of the flash lamp from red blood capillaries on the bottom of the eye.

If the flash lamp is distant from the lens, or if by some reason the pupil of the eye is narrow, or the person doesn't look into the lens, then the eyes have got their normal color.

Many cameras use a mode "red eye prevention". A bit of second before main flash a bright lamp (LED) or a slave flash lamp blinks. So pupils of human eyes become narrower.

Instead of a flash lamp skilled photographers use bright diffuse illumination. They get nice soft shadows, and never get red eyes.

A snake on the night path
Snake in night

Animals have got red blood, too. On the photo one cat doesn't look into the lens, or maybe it has got narrow pupils of its eyes. So its eyes are normally green.

One eye of other cat looks into the lens, and we see red color like on portraits of humans. The second eye looks some apart of the lens. So we see the mixture of two colors red + green = yellow .

On we web there are many different photos of cat's eyes. But the effect you may see perhaps only at night photo with a flash lamp.

 

Red-Eye effect - for human and animals