The eyes are the body’s windows on the world. Like a video camera they detect a moving picture of the world and turn it into tiny electrical signals. These signals are nerve impulses which go to the brain to be sorted. In ancient times people thought that light shone out of their eyes onto what they looked at. Now we know that light rays pass from an object into the eye. Every second or two the eyelids blink and sweep tear fluid across the conjunctiva, washing away and dust and germs.
The image that forms on the retina when light passes through the lens is actually upside down. This is because of the way in which light rays are bent by the eye’s lens. The brain automatically turns the image the right way up, but you are never aware that this is happening.
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Fact File: There are six muscles to control the movements of each eye. Muscle (a) swivels it away from the nose; (b) towards the nose; (c) rotates it upward; (d) downwards; (e) moves it down and outwards and (f) moves it upwards and outwards. |
Picture Credit : Google