Urban Animal

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Dear UrbanAnimal:

I'm trying to help my 10-year-old daughter research the subject of cat vision. Can you tell us if cats are near-sighted and can they see colour? We've found several opposing views on the Internet.

Lindy and daughter Emily

 

They say eyes are the windows to the soul and I think that's especially true for our cat buddies. I find their eyes to be mesmerizing. Most importantly, however, those perfect peepers are also perfectly suited to a cat's needs.

Yes, cats tend to be near-sighted. While their close-up vision is highly evolved, their ability to see at a distance often seems lacking. Like many animals (including humans) a cat may fail to see a distant object until that object moves. With my own dogs and cats, I've often noticed that while they won't necessarily see me while I'm standing in my garden, if I call their names or wave my arms, they zero in and come to me. (Or not come to me, depending on the animal in question!) Cats are incredibly adept hunters. Relying on multi-directional ear movements and keen hearing, they pinpoint prey then target it with their powerful sense of sight.

A cat's ability to see in the dark is another example of its acute vision. Their retina is made up of the same rods and cones as found in human eyes, but behind the retina is an extra light-reflecting membrane called the tapetum lucidum. Rods are receptors used for low-light situations while cones process colour information. A human retina contains four rods for each cone. A cat's retina holds an incredible 25 rods for each cone. The arrangement of the nerves linking the cones causes a sort of super-compression of information to travel along one nerve fibre, requiring much less light in order for the cat to perceive objects. The reflective tapetum combined with the action of the cones combines to create a furry seeing machine. This would explain why your cat marches confidently in front of you while you fumble your way through a dark kitchen for a midnight snack.

Opthamologists currently believe cats can indeed see in colour but not in the same way as us humans. Going back to what I wrote above, you'll see that while cats have more rods which aid in low-light situations, we humans have six times more cones which process colour information. Since cats can't talk and tend to be uncooperative subjects, you can imagine setting up a kitty colour test would be difficult! But the present theory holds that lack of cones suggests a cat can't see red as well as some hues of orange and brown. If this is true, experts believe their vision is made up of blue, green and yellow. This theory carries over to dogs as well which begs the question: why do pet owners so often choose the colour red for their pets' food bowls, toys and accessories?

Although they may not be able to see red, the object is probably translated into a shade or shades of grey.

Cats' eyes are susceptible to a number of health issues and an annual veterinary examination will include an eye assessment. Some symptoms of eye problems include cloudiness, redness, discharge, staining or crustiness around the eye, deterioration or loss of vision, squinting, bulging or sunken eyes. Sometimes these symptoms can be secondary to other health problems so be sure to consult with your veterinarian if you're concerned about any facet of your cat's health.

 

Do you have a question, comment or suggestion you'd like to submit to UrbanAnimal? I'd love to hear from you! Please contact me at jacque-newman@rogers.com