Sudden rectus muscle palsy refers to paralysis of the eye muscles which may be caused by diabetes, tumor or peripheral neuropathy. 1. Diabetes: patients with abnormally high blood sugar and no timely control of diet, diabetes, can affect the optic nerve of the patient, the patient may appear sudden ophthalmoplegia, resulting in abnormal eye rotation. 2. Tumor: when the patient has a tumor in the eye, it will cause pressure on the surrounding nerves and tissues, causing the patient to develop neuropathy such as motor nerve palsy. 3. Peripheral neuropathy: When there is peripheral neuropathy in the patient’s eyes, such as inflammation, trauma, etc., it may affect the normal function of the nerves and muscles of the eyes, resulting in sudden ophthalmoplegia. It is recommended that patients with sudden onset ophthalmoplegia should consult a doctor to evaluate their condition and follow the doctor’s instructions.