THE SENSE OF SIGHT 

We perceive shapes, distance movement, color, heat and depth by our sense of sight. 

The organ for the sense of sight is the eye, which has the shape of a ping-pong ball.

The eyes alone can't make sight possible. They work with the brain and, on the outside, they need light to percive an image.

Some simple animals can only tell light from dark, but with vertebrates, the visual system is able to form images.

The ability to interpreted visible light information reaching eyes is called visual perception.

FUN FACTS

- People  blink 15 times per minute on average.

- Everything would appear two-dimensional to a person with only one eye.

- Newborn babies see everything upside down until the brain learn to

  process everything right side up.  

- Dolphins sleep with one eye open. Creepy ? Or super smart ?