The symptoms of levator muscle weakness are heavy eyelids and a feeling that the eyes cannot be lifted or opened. There are several causes: 1. congenital, caused by hypoplasia of the levator muscle; 2. acquired, caused by injury to the levator muscle; 3. fatigue, caused by excessive eye use and straining of the eyes. The majority of cases are fatigue-related. For example, if you look at your cell phone or computer too much, work too long, or don’t pay attention to the light, it causes fatigue and dryness of the eye muscles. These are the causes of muscle weakness, but the specific cause is recommended to go to the hospital for a good examination.