Cat sight has excellent night vision, but cats cannot see in total darkness. A special layer of cells called the tapetum lucidum reflects all available light and enables the cat to see very well in very dim light, so dim that we would consider it to be pitch black. It is this layer of cells behind the retina that will reflect and eerie glow when your cat’s eye reflects light. A cat's shining eyes usually appear greenish or golden. The eyes of the Siamese cat reflect a luminous ruby red. The cat sight ability to see well at night is an important adaptation to your Siamese’s nocturnal behavior and the ability to hunt prey at night.
The Cat sight can also differentiate movement at a much faster rate than a human can. This ability will attract cats to the slightest movement of things that are undetectable by us. Cats to not see as well as humans in bright light, this is compensated by closing the iris to a very narrow slit which improves the depth of field.
Contrary to popular belief that most mammals are color blind, cats can see some colors, and can differentiate between red, blue, and yellow lights as well as between red and green lights.
Cats have a third eyelid called the nictitating membrane , which is a very thin cover that closes from the side and can be visible when the cat’s eyelid is open. This membrane will be partially closed if the cat is sick. Some times during traveling I would medicate my Siamese because she would not travel well. The calming effects of the medication would cause her nictitating membrane to be almost fully exposed and she could not see well. If your cat often shows the third eyelid, than she needs to be taken to a veterinarian.
Cats do not have to blink their eyes on a regular basis like humans to keep their eyes lubricated. Cats however will squint and you can entice your cat to squint by talking to him gently and stroking him. A cat will blink slowly with only one eye at time, an advantage for a hunter. If you blink slowly to your kitty, he may blink back at you.
Cat eye color can come in a very wide variation. The most typical colors are gold, green, and orange. The beautiful blue eye color is usually associated with the Siamese cat, but is also found in white cats. Heterochromatic eyes can occur in cats producing one blue and one yellow eye.
Cat Sight to Siamese Cat Behavior