The eyeball lies nestled in fat within the orbital cavities (two bony sockets) of the |skull|, where it is situated above and lateral to the center. Of all the senses, eyesight is often considered most important. According to one estimate, four-fifths of everything we know reaches the |brain| through our |eyes|. The |eyes| transmit constant streams of images to the |brain| by electrical signals. The |eyes| receive information from light rays. The light rays are either absorbed or reflected. Objects that absorb all of the light rays appear black, whereas those that reflect all the light rays appear white. Colored objects absorb certain parts of the light spectrum and reflect others. When you look at something, the light rays reflected from the object enter the |eye|. The light is refracted by the |cornea| and passes through the watery |aqueous humor| and |pupil| to the |lens|. The |iris| controls the amount of light entering the |eye|. Then the |lens| focuses the light through the vitreous humor onto the |retina|, forming an image in reverse and upsidedown. Light-sensitive cells in the |retina| transmit the image to the |brain| by electrical signals. The |brain| "sees" the image right side up.
