Here are some of the most common questions and myths when it comes to cat vision explained to us by PetMD:
Can cats see in the dark?
People often believe that because cats stalk around our house long after the humans go to bed, that must mean they have some kind of night vision humans lack. As it turns out, that is only partially true.
Cats can certainly see better in the dark than humans, says Dr. Gaylord Brown, chief veterinarian at D.E.L.T.A. Rescue, a large no-kill, care-for-life animal sanctuary. “Cat’s only need about 15 percent of the light humans need to see,” he explains. But felines aren’t walking around with vivid night vision the way many people imagine.
“It is estimated that cats can see six to eight times better in the dark than humans,” says Veterinarian Ophthalmologist DJ Haeussler, who runs the Animal Eye Institute in Southern Ohio.
Are cats colorblind?
When it comes to cat vision, the myth that cats “can’t see color” manages to persist despite enormous evidence to the contrary. To be sure, they see color differently than the average human. But their seeing isn’t all in black and white.
Cats are generally accepted as dichromats, meaning that they have two types of cones that see colors. There is some evidence that cats may even have three types of cones, which would make them trichromat.
“To see color, animals need to have receptors in the retina known as cones,” says Dr. Brown. “What is true is that cats only have cones that detect blue and green. There are no cones for red. Therefore, cats have a more muted sense of color. Similar to a person who is color blind.”
Why do cats’ eyes glow?
“Cats eyes glow when light is shined at them due to a reflective structure that is part of their retina known as the tapetum lucidum,” says Dr. Haeussler. “This structure amplifies light to better allow the cat to see in dim light.”
Cats are not the only animals who have this tapetum lucidum. Dogs, cows, and horses, ferrets, and other animals have them, too. Humans don’t have the tapetum lucidum because we are designed to see better during the day.
Even more fascinating, different breeds of cats’ eyes glow differently. While most cats’ eyes glow bright green, a Siamese’s eyes glow more yellow. This variation comes from the amount of zinc or riboflavin present in the pigment cells present within the tapetum lucidum.
Do cats and dogs see the same way?
According to Dr. Brown, dogs have a smaller area of binocular vision than cats. Binocular vision helps to judge distance. But cat has less peripheral vision than most dogs.
“This is due primarily to the placement of the eyes in the head,” Dr. Brown says. “The cat’s pupil is slit shaped and has a much more complex set of muscles controlling the pupil than the dog. The dog’s pupil is round. The tapetum, which reflects lighting the eye, is relatively larger in the cat. Cats depend more on contrast and degrees of brightness than dogs, due to the differences in the retinal cones. The muscles of a cat’s eye are much better at rapid eye movement than those in the dog, which allows them to better track small objects such as mice and birds.”
For these reasons cats clearly have an advantage over dogs when it comes to vision.
Do cats have a third eyelid?
In fact, they do! They have third eyelid, between the regular eyelids and the cornea giving added eye protection. That third has a gland at the bottom that produces extra tears.
Protecting your cat’s eyes
We, as their human caretakers still have a big responsibility, not only just to understand how their vision differs from our own and what they see versus what we see, but also to protect them.
“Other than acute trauma, most vision loss occurs slowly over time,” says Dr. Brown “The sooner a disorder affecting the vision is diagnosed the better the probability of stopping the progression and reversing the vision loss. The single most important thing a cat owner can do is have their cat’s eyes examined at least once a year.”