This is quite a common condition called myokymia. In the majority of situations, when your eyelid is twitching, it is a benign condition that will not cause any long-term damage. Generally, the biggest concern I hear is the subtle twitch of the eyelid, while not very noticeable to observers, makes you feel like you are losing your mind. I assure you from an eye standpoint, you are not!
The most common reasons your eyelid is twitching are increased stress and/or fatigue or increased consumption of caffeine or alcohol. Controlling these 4 things will generally resolve the issue. It has been suggested that an over-the-counter antihistamine eye drop (Alaway or Zaditor for example) twice a day can help resolve the issue as well.
In the rare case you start seeing other symptoms associated with the twitch (complete facial twitch, blurred vision, tingling in your extremities, etc.) you should always consult a medical professional. If you have any questions or comments, please send an email to drlillie@familyvisionoptical.com.