Myokymia: the irregular firing of multiple motor units resulting in a visible rippling under the skin.
The jerky contraction of muscle fibers is a condition known as Myokymia. It can occur anywhere in the body, but is particularly annoying in the eye. The twitching can be caused by a temporary imbalance in your body's chemistry and this happens most frequently when you are tired, under stress, not eating correctly or consuming caffeine or nicotine. The good news is that it is not serious and usually goes away with rest and proper nutrition.
