For as long as scientists have been studying cats, they’ve been tossing around theories about feline vision. Some were just silly, like “cats are completely color-blind and only see in black and white,” and some were incomplete, based only on a part of a cat’s eye anatomy. Recently, photographer Nickolay Lamm consulted with Kerry L. Ketring, DVM, DACVO, of All Animal Eye Clinic; Dr. DJ Haeussler of The Animal Eye Institute; and the Ophthalmology Group at Penn Vet and put together some pictures to show us what that research means. In these images, which Lamm recently published in his blog, human vision is represented by the top photo and cat vision by the bottom one.
A human being with normal vision can see about 180 degrees. Cats, on the other hand, have a visual field of 200 degrees. The black areas in the top photos indicate the difference in visual field.
We humans have a narrower visual field, and we see less clearly at the edges of our visual field than cats can.
Cats have many more rods (light receptors) in their retinas than humans do. Add to that their relatively large eye size and the reflective layer that makes feline eyes shine blue or green in the dark, and you have a recipe for good night vision.
I always figured cats were farsighted because of the shape of the lens of their eyes, but apparently their distance vision is between 20/100 and 20/200. That is, what we can see clearly at 100 to 200 feet, a cat can only see clearly at 20 feet. I feel your pain, kitty! Alas, they don’t make glasses for cats.
Because we humans have three types of color receptors in our eyes, we are able to see a rich and highly varied palette. Cats, on the other hand, are able to perceive colors in the blue-violet and green-yellow range. But even in that color range, because they have fewer color receptors, the colors they see are not as bright as the colors we see.
Cats were originally thought to be dichromats — that is, they could only detect two types of colors — but new research is suggesting otherwise. Cats may have a third type of receptor that peaks in the green area of the color spectrum. This would mean that unlike dogs, cats can perceive some intensity of green.
What do you think? Does your kitty experience lead you to think this is accurate — or maybe not so much? Sound off in the comments.
(Images by Nickolay Lamm, used by permission of the artist)
About JaneA Kelley: Punk-rock cat mom, science nerd, animal shelter volunteer, professional cat sitter, and all-around geek with a passion for bad puns, intelligent conversation, and role-play adventure games. She gratefully and gracefully accepts her status as chief cat slave for her family of feline bloggers, who have been writing their award-winning cat advice blog, Paws and Effect, since 2003.