Why would my eye be twiching?

Eye Twitching. This is technically referred to as myokyemia. Most causes of this are benign and short lives. Stress, lack of sleep, and eye strain have all been implicated. Caffeine and alcohol are also thought to play a role in some instances. There are some much less common neurological disorders, so a physician evaluation is a good idea.
Muscles or nerves. Eye twitching can be caused by irritation of the muscles or nerves. Sometimes abnormalities of your blood salts (electrolytes such as sodium or potassium) can cause this. Chronic inflammation of the eye can also cause it. Most of the time, it's benign though irritating.
Agree. Sometime are very benign and excessive coffee intake and or lack of sleep are causing it.
Caffeine and... Caffeine, stress and lack of sleep are the top causes of twitching. Check out http://www.2020vision.Com/eye_twitch.Html for more info!