In ophthalmic surgery, surgical operations such as pulling certain eye tissues or compressing the eyeball often leads to bradycardia, arrhythmia even cardiac arrest, bradypnea, nausea and vomiting and elevated blood sugar level. The condition is called the ocularvagal reflex (OVR). Traditionally, when the bradycardia or arrhythmia happens, the operation has to be suspended, and atropine or isoproterenol is given intravenously to treat the bradycardia. Vagus nerve block may be an effective way to prevent and alleviate this vagal reflex. However it is difficult to perform the nerve block with anatomical landmark (blind) methods. In this study, the investigators used ultrasound-guided right cervical vagus nerve block to reduce the incidence of the OVR. The researchers hypothesized that low concentrations of lidocaine or ropivacaine can block the right cervical vagus nerve and reduce the incidence of intraoperative OVR. Researchers evaluated the changes of heart rate, blood pressure, oxygen saturation, and airway pressure in patients undergoing high-risk OVR surgery.

Inclusion Criteria:

• Patients received surgeries with high-risk OVR, including the strabismus surgery, the posterior scleral reinforcement, and the insertion of ocular implant.

Exclusion Criteria:

• Those who have pre-existed vocal cord damage before surgery (such as hoarseness, electronic laryngoscopy shows fixed vocal cords or arytenoid cartilage dislocation).
• Those with a history of surgery on the both sides of the neck (eg, thyroidectomy, carotid endarterectomy).
• American Society of Anesthesiologist (ASA) Grade > 3
• Patients with infection at the neck puncture site, or severe coagulation abnormalities before surgery, or a history of local anesthetic allergy, or who have a pacemaker.