Have you ever wondered why cat eyes glow in the dark?

          The reflective layer, the tapetum lucidum, on the surface of the retina increases the sensitivity of the retina and enhances the incoming image. It is this layer that causes the reflection to occur. Contrary to popular belief, cats cannot see in total darkness, but can see in very dim light. The ability to do this is largely due to the flexible muscles which control the iris. This iris opens and closes to allow available light to enter.

Cats see twice as well as humans see in the dark due to the tapetum lucidum, but the vision is very fuzzy. Cats do not use vision for detail but rather to concentrate on movement. This is how they hunt, looking for movement as opposed to a particular object.

Cats see very well at long distances, particularly 7 to 20 feet away, yet their up close vision is not very good at all. If you have ever tried giving your cat a treat from the palm of your hand and it seems that he cannot find it, now you know why.

It is debated as to how much cats see in color. Some experts believe that cats can only distinguish between the colors red, blue and white. Other believe the colors green, yellow and white appear gray to the cat. Not everyone agrees on which colors cats can tell apart, but they all agree that cats can see certain colors.

Cats have a third eyelid known as the haw. It is said that this third eyelid continually flicks across the surface of the eyeball while the eye remains open. This explains how a cat can seemingly stare out 'forever' without blinking. The haw keeps the eye lubricated while the cat stares down possible prey or you, the owner. If this third eyelid is constantly visible, it is a sure sign that your cat is ill.

FUN FACT! Cats use their whiskers to determine dimensions of spaces in the dark. Since cats don't see well up-close, whiskers also help them get information from captured prey.

- Cat