Blepharospasm or benign essential blepharospasm is a bilateral abnormal involuntary contraction of the muscles of the eyelid causing closure of the eyelids.
Eyelid twitching, or myokymia, is an involuntary, unpredictable and repetitive movements of the eyelid muscles especially the upper eyelid. It can occur in lower eyelid and also in both upper and lower eyelids at the same time.