The Eye

The eye, part of our central nervous system, is built along the principles of a camera. A complex series of actions takes place each time we look at an object.

Light rays reflect from the object to the cornea, the "front window" of the eye that transmits and focuses light. Next, the light travels through clear aqueous fluid and through the pupil (the black, circular opening in the center of the iris), which changes size to determine how much light comes in. A transparent lens focuses the rays, which move through the vitreous, a clear, jelly-like substance that fills the middle of the eye.

Finally, when the light rays reach the retina, they appear as an upside-down image. The retina converts this image into electrical impulses that are transmitted along the optic nerve to the brain.

Click here for eye diagram.