Some say cats see only the color purple, some say they only see red. Do they see color or not, and why not?
Cats (and dogs too) have cells in their eyes that respond very well in bright and dim light. As you know, cats can see very well at night. Cats use cells called rods that sensitive to dim light. You can find those rods (responsible for black and white) in a lining at the back of the eye called the retina (the nerve center at the back of the eye). When light calls on the rods, they send a message to the brain to explain the image that they see. For the bright light of day, you need cells called cones (responsible for converting light into color). Those cones in your eyes make sure you can see colors. We humans have three kinds of cones (blue, red and green), so we can see in full color. Cats and dogs only have two cones and those are sensitive to blue and green light. They do see some color, but not everything. In cats, rods greatly outnumber cones.
Theoretically, color perception is possible since the eye has some cones, but distinguishing color isn’t necessary for cats. Brightness is far more important. He can see in the dimmest of lights; his eyes can open about three times as wide as the human pupil and let in as much light as possible at the normal “hunting” times of dawn and dusk. – petplace.com
Glow In The Dark
Cats eyes do not glow in the dark. Cats have cells behind the retina that act like a mirror. These cells are found in the tapetum, which is a part of the eyes. These cells reflect the light back, giving the rods and cones another chance to pick up the small amount of light that is available at night. It is the tapetum that makes cats and dogs eyes like they glow in the dark, but it’s only a reflection.
Humans don’t have a tapetum. You may have noticed that if you use flash to take a photo, humans tend to look like they have red eyes. This is because there is a reflection of the red blood vessels behind our retinas. If you took a flash picture of your dog, you might see yellow or orange eyes instead. This is a reflection of the light of the flash by the dog’s tapetum. – Kittyshow
Test results show that cats respond to the color purple, blue, green and Yellow, while red, orange and brown colors on the other hand are not responded to. Those colors that can’t be seen are most likely seen as shades of gray or purple in the eyes of a cat. Cats also seem to see less saturation in colors than we humans do. This means that cats do not see colors very intense or vivid. Blue and green appear to be the strongest color. Test also shows that cats can distinguish between more shades of gray than humans can. (wikianswer.com)
Because of the differences between human and cat retinas, the animals can see using one-sixth of the amount of light people need: At night, for example, objects appear six times brighter to a cat than they do to humans, which helps the animals hunt. In addition to better brightness vision, cats can also detect minute movement, which is easily missed by people. – Petplace.com