It may seem a bit odd as your brain produces the image you ‘see’, however your eyes collect all the information the brain uses to create the image. They take pictures of the world around you and send them to your brain, and your brain then works out what your eyes are seeing.
The cornea is the see-through skin covering the front of your eyes. It bends, or refracts, the rays that pass through the round hole of the pupil.
The iris controls the amount of light entering your eye. It is the coloured part of the eye surrounding the front of the pupil.
The rays then pass through the lens, focuses them on the retina.
The retina, which sits at the back of the eye, is a thin layer of tissue containing millions of tiny light-sensing nerve cells. These nerve cells are called rods and cones because of their distinct shapes. Rods ‘see’ black and white and cones are responsible for colour vision.
Cones are concentrated in the centre of the retina, in an area called the macula, and function best in relatively bright light. Rods are located outside the macula and extend all the way to the edge of the retina. They provide peripheral vision and allow the eyes to detect motion and help us see in dim light and at night.
Once light meets the retina the process of sight begins. They turn the picture into an electrical message for the brain. The optic nerve sends these messages to a part of the brain called the thalamus via the optic nerve. This area combines information from both your eyes and then sends it to another area of your brain called the visual cortex. This is a specialised part of the brain which processes visual information and is located at the back of the brain. It interprets the electrical signals to obtain information about the object’s colour, shape and depth. Other parts of the brain then put this information together to create the whole picture.
“Humans have five senses: the eyes to see, the tongue to taste, the nose to smell, the ears to hear, and the skin to touch. By far the most important organs of sense are our eyes. We perceive up to 80 per cent of all impressions by means of our sight. And if other senses such as taste or smell stop working, it’s the eyes that best protect us from danger”. Quote from http://www.zeiss.com.au