Cats' eyes point forward, like human eyes. Each eye has one spot that sees the same thing as the other eye. Nerves communicate the image to the brain, which puts the two together as one clear image.

Human retinas rest at the back of the eye straight on, so we look straight ahead to see. With Siamese cats, the left retina tilts in toward the right and the right retina tilts left. If the cat looked straight ahead it would see two different images. Siamese cats have compensated by crossing their eyes to place the retinas in line and to see more clearly.