Common causes of upper eyelid muscle weakness include genetic factors, diabetes, myasthenia gravis and visual fatigue. 1. Genetic factors: mainly the nucleus of the motoneuron or hypoplasia of the levator ani muscle, which is autosomal dominant or recessive, can lead to levator ani muscle insufficiency or loss of function, which is manifested as levator ani muscle weakness. 2. Diabetes mellitus: some long-term diabetes mellitus patients, peripheral neuropathy can occur, so that the motor nerve paralysis, can be manifested as ocular muscle weakness. 3. Myasthenia gravis: Myasthenia gravis is an autoimmune disease caused by the dysfunction of nerve-muscle junction transmission, which is mainly manifested as partial or generalized skeletal muscle weakness and fatigue, and can cause upper eyelid muscle weakness. 4. Visual fatigue: excessive fatigue, poor sleep, staying up late, excessive use of eyes, etc. can cause visual fatigue, resulting in upper eyelid muscle weakness, which can be relieved after rest. When the symptoms of episcleral muscle weakness persist, the patient should go to the regular hospital in time for examination, to clarify the cause of the disease, and follow the doctor’s instructions for treatment.