NotEinstein
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"Seeing stars" is one of several ways one can perceive light without actual light reaching the eye. These phenomena are called "phosphenes." Phosphenes are caused by some outside force signaling cells in the retina to send electric impulses to the brain. The visual centers of the brain think this is normal visual activity and perceive it as such.
"Seeing stars" is caused by most common type of phosphene: the pressure phospene. Direct pressure, in this case a blow to the head, causes the retina cells to misfire. This can also be caused by a sneeze or pressure applied to the eye. For example, if you put light pressure on one side of your eye you will see a bright dot appear on the opposite side.
Phosphenes can also be caused by electricity, causing the affected person to see a bright flash. Work is being done to take advantage of this by stimulating retina cells directly using electrical impulses. When these impulses are timed with a video camera they can simulate normal reaction to light, helping blind people with functioning retina cells regain some of their eyesight.
 Posted 5296 day ago
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