Feline Sense Series: Anatomy of a Cat Eye

It's a myth that cats can see in complete darkness. The part of the feline's retina called the "tapetum lucidum," acts like a reflector in the eye and bounces light to the back of the retina, thus the appearance of "glowing" eyes which a cat exhibits at night when their eyes are struck with a beam of light, such as car headlights.

It's a myth that cats can see in complete darkness.  The part of the feline's retina called the "tapetum lucidum," acts like a reflector in the eye and bounces light to the back of the retina, thus the appearance of "glowing" eyes which a cat exhibits at night when their eyes are struck with a beam of light, such as car headlights. 

Because of the so-called "witches" holiday, Halloween, this oftentimes cause people to see malice where there is none in that "eerie" glow of a cat's eye (which is why ALL cats, black as well as every color, should be kept inside - not just during Halloween, but all year long). 

Even though cats cannot see in complete darkness, they can see quite well in extremely dim conditions, thus being deemed nocturnal creatures.  In low light, cats' eyes are able to function in approximately one-sixth of the light needed for human vision. This ability, however, comes at the expense of their daytime vision.

Cats are relatively shortsighted in daylight and see things somewhat blurred - like a nearsighted human trying to see a faraway object - but the stealthy feline can detect the slightest movement at almost any distance.  Felines have incredible depth perception, allowing them to judge distances much better than humans.  As unbelievable as it seems, a cat's sense of  "sight" is actually near the bottom of their cognitive abilities.

The of a cat's eye is relatively larger than that of a human.  This enables a larger pupil and, therefore, more light to enter the eye. Generally, the lens is more curved allowing sharper focusing - even at the edges of the lens. The of the anterior chamber and the curvature of the cornea is also greater, which helps more light to be refracted onto the light-sensitive retina.

Finally, cats' eyes also reveal what a cat is feeling or thinking. The pupils of a feline's eyes can dilate up to five times their normal when frightened or threatened.  In normal light, a happy cat should have small pupils that look like little slits in the center of the eyeball. Eyes that are half closed signify a contented, relaxed feline.

For most cat owners, however, their furry friend's eyes - with all the elements, components and mystery which compose the complicated function of vision - being closed dreamily is the most commonly witnessed occurrence when noticing your cat's eyes.

Sandra L. Toney has been writing about cats for 15 years.  An award-winning author of eight books, such as The Simple Guide to Cats and The Little Book of Cat Tricks, Toney is a professional member of the Cat Writers' Association.  She lives in Indiana with her husband and three spoiled felines.

To read the next part of the Feline Sense Series, click on the links below.

Feline Sense Series: A Matter of Taste

Feline Sense Series: Nosing Around

Feline Sense Series: All Ears

Feline Sense Series:  Touchy Feely

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