The Eye

We are able to see things because light waves bounce off the object into our eye. However when the light reaches our eyes several things must happen so that we can see. Firstly, the light must pass through a transparent part of the eye called the cornea. The cornea is curved and bends light inward. The light is bent even further as it passes through a liquid behind the cornea. Next, light passes through the black opening in the middle of the coloured part of each eye. This part of the eye is called the pupil. The coloured part is called the iris, and it makes the pupil change size depending on the different amounts of light. For example when the light is bright, the iris makes the pupil small.

Once light passes through the pupil, the light enters a part of each eye known as the lens. Like other kinds of lenses the lens of each eye bends light. Muscles as the sides of the lens change its shape so it can bend light in two ways. After the light passes through the lens the light is bent still further. This bending takes place in a jelly like matter inside each eye. This is also what helps your eyes to keep their shape. Finally the light forms an image on part of the inside wall of each eye. This wall is called the retina and is made up of millions of special cells. These cells send message about the image to your brain. These messages travel along a nerve called the optic nerve. Once the messages reaches your brain you are able to see.