The twitching of the left eyelid can be caused by physiological reasons, but also by trauma, eye diseases and intracranial diseases and other pathological reasons. 1. Physiological causes: If you are usually nervous, sleep deprived and stressed, it is very likely to cause eyelid twitching, which is a physiological phenomenon and can be relieved by proper rest. 2. Pathological causes: trauma, eye diseases and intracranial diseases may lead to eyelid twitching all the time, it may be the left eyelid or the right eyelid. (1) Trauma: Trauma to the eye (e.g., blows, sharp instrument injuries, etc.) can affect the facial nerve, which in turn leads to twitching of the eyelid where the facial nerve innervates. (2) Eye diseases: Some eye diseases (such as impingement, trachoma, conjunctivitis, etc.) can stimulate the facial nerve endings, resulting in constant twitching of the eyelids, as well as symptoms such as eye pain, foreign body sensation and abnormal secretion. (3) Intracranial diseases: Some intracranial diseases (e.g. intracranial cysts, cerebral hemorrhage, etc.) may injure the root of the facial nerve, thus causing the eyelid to twitch. If the left eyelid keeps twitching and cannot be relieved after resting, it is recommended to go to the hospital in time to find out the specific cause of the disease and then carry out targeted treatment.