This kind of stuff fascinates me too. Here are some articles I found about this topic:
Keeping in mind that your cat evolved from hunters, you can understand why his sense of sight is one of his strongest. But cats are generally considered colorblind.
The retina – the nerve center at the back of the eye – contains cells called rods (responsible for converting light into color) and cones (responsible for black and white). In cats, rods greatly outnumber cones.
Theoretically, color perception is possible since the eye contains 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.
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 - another benefit for a hunter.
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How Well Do Cats See?
Cats can see almost as well as humans can, and at times better. Cat vision is designed for detecting motion, useful for hunting. Like humans, cats have binocular vision, although not as well tuned as in humans. This means a cat most likely sees in 3-D, as do humans, which is very useful for judging distance. Cats appear to be slightly nearsighted, which would suggest their vision is tailored more for closer objects, such as prey, that can capture within running distance. Objects farther than several hundred yards rarely interest a cat. Cats have the ability to jump from as much as 6 feet onto a narrow window ledge without touching the window. This feat would require not only excellent balance, but also precise distance judgment. Cats have both rods and cones in the retina. Rods are the receptors that the eye uses for night time viewing and sudden movement. Cones are used during the daytime, and process color information. Cats have more rods than cones, as compared with humans, making cat night and motion vision superior to humans.
In low light, like night, color and hue are not perceived, only black, white and shades of gray.
Cats have an elliptical pupil which opens and closes much faster than round types and allows for a much larger pupil size. This allows more light to enter the eye. Cats also have a mirror like membrane on the back of their eyes called a Tapetum. It reflects the light passing through
the rods... back through the rods a second time, this time in the opposite direction.
The result is a double exposure of the light, which permit cats to see well in near darkness.
Although a cat cannot see in total darkness, a partly cloudy night sky with some stars will provide enough light for cats to hunt and see movement, even in the cover of most brush. At nigh, a cat relies on it's extremely sensitive hearing and directional ear movement to locate the general position of prey, then targets and captures the prey using it's keen eyesight.
The yellowish glow you see when you shine a light into cat eyes at night,
is really your light reflecting off the Tapetum membrane.
Human Night View
Cat Night View
Do Cats See in Color?
We believe cats do see in color, although not exactly the way we do. In our tests, cats appeared to distinguish between the low to mid light wave spectrum (higher frequency), meaning cats
responded to the colors purple, blue, green and yellow range. Red, orange and brown colors
appear to fall outside cats color range and are most likely seen as shades of gray or purple.
Cats appear to see less saturation in colors than do humans,
meaning cats do not see colors as intensely or vibrantly.
Blue and green appear to be the strongest colors perceived by cats.
Our tests suggest cats can distinguish between more shades or levels of gray than can humans.
Human View
Cat View
No Color View
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