What does eyelid twitching mean?

One or both at once : Monocular eye muscle twitch often due to eye muscle strain ie prolonged reading, improper correction etc. Binocular suggests neurological conditions as meig, blepharospasm etc. See an md eye doc to make sure.

Myokymia: Random twitching of an eyelid, which happens in normal people, is called myokymia (an involuntary, spontaneous, quivering of a few muscle cell bundles within a muscle). Myokymia starts and stops spontaneously. In the eyelids, it can last a few minutes to a few days. It can be caused by stress, dry eyes, lack of sleep.

Eyelid twitch: Normally eyelid twitching means nothing, other than that those muscle fibers are tired. Twitching in the upper or lower lid briefly in one eye is nothing to be concerned about. Forced eyelid closure on both sides can be a problem, and it feels very different. http://www.neurocuro.com/eyelid-twitching/