How Cat's Eyes Work

A cat's vision is almost as good as a humans, and sometimes better. Cat vision is superior in detecting motion. Cats, like people, have binocular vision, although theirs is not as well defined. It's believed that cats see the world in 3-D, which is useful for judging distance. A cat's pupil opens and closes faster than round type pupils, and accommodates larger sized pupils, and allows more light to enter the eye. However, cats appear to be a bit nearsighted, which means their vision is better for hunting. Most times, objects that are far away will rarely be of interest to a cat.

The Tapetum is a mirror-like membrane in the back of their eyes. This reflects light as it passes through the rods into the eye, and reflects out of the eye. The cat eye has a combination of oval-shaped pupils and the Tapetum which allows them to see extremely well in near dark or dimly illuminated environments.

At night, cats do see only black, white and shades of gray, not colors. Their eyes have rods and cones in the retina. Rods perceive sudden movement and provide nighttime vision ability, while cones provide daytime vision and color sensory. Cats have more rods than cones, which makes their ability to see at night and detect motion far superior to the human eye.

The eyes of a cat respond to purple, blue, green and yellow colors. Darker colors, such as red, orange and brown colors are most likely seen as shades of gray. Cats find prey by detecting motion. Background changes or colors are not what attracts cats, it's the motion of the prey.

The myth that cats can see very good in darkness, is not entirely true. Actually, in total darkness, a cat cannot see any better then we can. But, they do possess excellent vision in low levels of light.

Third Eyelid

Every cat has a third eyelid. It's a white-colored, thin film that can actually cover the entire eye surface. The third eyelid acts similar to a windshield wiper to clean debris or dirt from the surface of the eye, and to redistribute tear production over the cornea.

The third eyelid will cover over a cat's cornea when they are sleeping. But, if a cat is ill, the third eyelid will partially close over the eye, and indicates veterinary care is necessary.

Cat Trivia:

• Cats cannot see directly beneath their noses. Cats smell food, but if it is dropped directly under their nose, they will need to sniff around before finding it.

• Cats are not colorblind. Although, cats do not see colors as vividly as we do, they can see some colors.

• A cats vision is 20/100 as compared to a humans 20/20, or about six times greater. A cat has enhanced vision for things far away, but things up close can appear fuzzy or blurred. Most likely, this is why cats need to sniff before they greet other cats.

• Most cats with white fur and blue eyes are deaf. And, if a white cat has odd-eye colors, such as one blue and one green eye, it's likely they will be deaf on the side with the blue eye.

The pupils of a cat's eye should be equal in size. Different sized pupils can indicate eye problems, such as:

• Inflammation of the eye

• Neurological eye disorder (Horner's syndrome)

• FeLV (feline leukemia virus)

• Tumors within the eye

• Central nervous system injury

A cat's pupil produces a lot of expression, from a tiny slit to a large round orb within the iris. When a cat is in bright light, the tiny slit makes them appear mysterious. A dilated pupil can warn of anger or fear.

When a cat is chasing prey, the pupils will be large and round, and their whiskers poised and pointed forward. The whiskers let the cat know when their prey is within striking distance.

Cats of different breeds have unique eye shapes, sizes and colors. American shorthairs and mixed breeds usually have big round eyes in many colors, such as copper, orange, green, and blue. Many oriental breeds have almond shaped eyes and eye colors ranging from deep blue, turquoise, and green.

The cat's eye has long been a curiosity and mystery. A cat's eye is beautiful, and many people love the beautiful eyes of a cat. Unfortunately, the cat has suffered, many times, due to myths. Although untrue, some people believe a cat's eye is associated with wicked and evil scenarios.