People once thought all cats were completely color blind, but research has shown that cats can distinguish a few colors. It wouldn't matter if your tiger tabby cat were another color; she'd still see the world in a limited color spectrum. And don't worry: Tabby's vision works well for her.
Thanks to the rods and cones in human retinas, most of us can see the full range of the color spectrum. Rods act as receptors for light brightness; cones are receptors for color. Humans have three kinds of cones, allowing us to see blue, red and green. When the rods are exposed to light, they send a message to the brain explaining the black and white image they see. The cones sense the different amounts of color in the image.
Tabby also has both rods and cones, but her cones are different from ours, making her color vision limited compared with normal human vision. According to Professor Paulette Clancy of Cornell University, the cones of all cats are sensitive to blue and green light, so they can see a few colors. A cat's color vision is similar to what a colorblind human sees. She can see blue against other colors fine, but she doesn't see colors on the red end of the spectrum the same way we do.
Don't feel bad about your cat's limited color vision. Cats are naturally nocturnal. Differentiating color isn't important for cats, but navigating in dim light is, so Tabby has superior night vision. Her level of retina illumination is much higher than yours. Her rods can pick up the faintest light source, and instead of being absorbed at the back of the eye, it's reflected back to her eye's receptors. That's why Tabby's eyes will "light up" when you shine a light at her in the dark. According to Dr. Arnold Plotnick of Manhattan Cat Specialists, cats can see in about one-sixth the light that humans require. All of this is essential help when she's hunting.
Seeing What She Needs to See
Not only is her color vision poor, but your cat also has poor detail vision compared with normal human vision: She sees best at about 2 1/2 feet, according to the Cat Care Clinic's article "Feline Eyes and Vision." Again, nature took care of her, because her other senses compensate for what she's missing visually. Her vision is suited for focusing on one object in a narrow field when hunting, and it's great at detecting movement. Tabby's superior sense of smell, her excellent hearing, sensitive paw pads and whiskers all work together to give her the tools she needs to navigate in places where her vision is lacking.