Inclusion Criteria:  • Adult patients > 18 years old.  ASA I and II. Patients scheduled for strabismus surgery.  Exclusion Criteria:  • ASA class > II.  Patients with known hypersensitivity or contraindication to any of the study medications. Patients who had chronic nausea and vomiting or experienced retching, vomiting, moderate to severe nausea in the preoperative day. Patients who had received an antiemetic drug in the preoperative day. Patients with a body mass index ≥36. Pregnant or breast feeding female patient. Patients with gastrointestinal diseases. Patients with a history of motion sickness, diabetes mellitus, and GIT pathology (gastritis, hematemesis, peptic ulcer).