2017-08-10 / Columnists

Pets, Pets, Pets

He has “eyes like a cat” describes someone who can see what others do not. Is feline vision really superior to the eyesight of humans and other species? The answer is a mixture of yes and no.

Ways cat vision is superior:

*Peripheral vision- Humans have a 20-degree range of peripheral vision on each side. Cats can see 30 degrees on each side. Their visual field overall is wider—they see 200 degrees compared to our 180 degrees.

When I was in Parkside Junior High (now Ames Middle School) in Massapequa, I did a science project testing people’s peripheral vision and reaction time. I held a ruler vertically in varying field of vision positions at the side of the subject’s head, then let go without warning, and recorded how many times the subject caught the ruler before it touched the floor. This may be a fun game to try with your cat using a heavy cat toy such as a ball, and testing the cat’s range of peripheral vision. On second thought, I must be delusional. No cat would stand still long enough for you to measure.

This kitten is a Siamese mix so his blue eyes are not genetically linked with deafness. This kitten is a Siamese mix so his blue eyes are not genetically linked with deafness. *Night vision- Cats see six to eight times better than we do in the dark, but they cannot see in complete darkness. First they have more rods in their eyes, meaning they detect more light. Also, like other nocturnal hunting animals, cats have a layer of reflective tissue in the back of their eye called the “tapetum lucidum.” It acts as a mirror and bounces light that hits the back of the eye through the retina again for a second chance to “see” it. The tapetum lucidum is also the feature that makes cats’ eye shine in the dark. Cats often have eyes that glow bright green, though Siamese eyes usually glow bright yellow.

In addition, the feline muscles of the iris surrounding the pupils are constructed in a way allowing the eye to narrow to a vertical slit in bright light and to open fully in very dim light. This allows maximum illumination. The vertical slits permit cat pupils to change size faster than ours do. The smaller the pupil, the less light comes in. Cats are less likely to get blinded by sudden changes in light levels than we are.

When we look at proportions, a cat’s eyes are significantly large when compared to the size of his head which is another typical trait of nocturnal animals. Think of the wide eyes of the owl or slow loris. Large eyes allow nocturnal animals to take in more light when wandering in their dark habitats. In our culture, large eyes are also perceived as beautiful. Feline eyes are part of their mystique.

*Detect movement- Cats’ eyes are designed to de- tect the slightest movement to help them stalk and catch prey, even tiny creatures. Have you ever found your cat staring at something that isn’t there? Chances are Whiskers spies a tiny bug or spider hanging from a barely visible string of silk. Very few insects go undetected when your cat is on guard duty.

*Third eyelid- While the third eyelid is not seen when a cat’s eyes are wide open and awake, a hint of it may be visible when a cat suddenly wakes from sleeping. The cat’s third eyelid is located in the inward corner of a cat’s eye. It appears as a whitish film that in some cases may almost cover the entire eye. However, the third eyelid should not show under normal circumstances. If it does, the cat is either ill or something else is wrong. A vet exam will verify the underlying cause.

Ways cat vision is flawed:

*Detecting details during daytime- If normal human vision is 20/20, then that of the cat is 20/100. Felix has keen vision for objects far away, but things up close may appear fuzzy or blurred. Perhaps this is why cats do the sniff test when greeting friends. In cats, the balance of rods and cones doesn’t allow for good detail vision. (Cones detect color.) Because cats have more rods and fewer cones than we do, they don’t perceive things like leaves on trees or writing in books in the way we do. Many researchers do, however, believe cats are farsighted because the cat’s lens doesn’t change shape to compensate for focusing close up, and that they see best at a distance of two or three feet.

*Cats aren’t color-blind but... It’s thought cats do not see colors as intensely as we do. Cats have been shown to respond best to purple, green, blue and yellow while they don’t respond well to colors in the red, orange or brown range. Actually, color detection doesn’t seem to play an important role in feline survival skills.

*Eye color-linked defect- All kittens are born with blue eyes. The color starts to change when they are about six weeks old. Most adult cat eyes are amber or green. Blue eyes are usually only found in white cats and Siamese cats. White cats with blue eyes are often deaf. This is because a gene which causes deafness is linked to the blue eyes and white fur genes. White cats with odd-colored eyes (one blue, one amber) are typically deaf in the ear on the same side as the blue eye.

*Blind spot- Cats have better horizontal than vertical vision. They cannot see directly beneath their noses. You can test this by offering Fluffy a treat. He can smell it, but if you drop it directly beneath his nose, he’ll have to poke around a bit before finding it. When teaching infant kittens to eat solid food, it’s best to use a flat plate because they don’t see into a deep dish. Plus, they may walk onto the flat plate and then have to lick your delicious kitten cuisine off their paws. This way they learn to eat on their own.

For Adoption at Babylon Town Shelter (631-643- 9270) Lamar St. W. Babylon- Jacob 7-380 has exquisite green eyes. He’s also very friendly. He and his brother Edward lost their home after an eviction. Twin kittens-Ernie and Robbie 7-287/88- love each other and everyone they meet. The boys are light orange, and “purrfect,” as we say in the cat rescue business.

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