Cats have the largest eyes of any carnivore, proportionate to head size. They are large and seated deep within the skull. This limits the amount the eyeball can move, but it allows for excellent peripheral vision, especially of moving objects. That is why a cat will dart his head to the side once he has detected movement from the side.

The vertical pupil responds quickly to changes in light, enlarging in the dark and closing to a slit in bright light. Cats are somewhat nearsighted; they can't see close-up objects too well. The pupils are closed to a slit to help cats focus on nearby objects. Cats can see a limited range of colors.