The Effect of a Laryngeal Mask Airway on Optic Nerve Sheath Diameter

Inclusion Criteria: * In order to be eligible to participate in this study, a subject must meet all of the following criteria: aged 18 years or older, ASA I or ASA II, scheduled for elective surgery under general anesthesia, with a planned duration of \> 30 minutes, that can be routinely performed with a LMA. Exclusion Criteria: * Scheduled for head or neck surgery * Scheduled for neurosurgery * Scheduled for laparoscopic or thorascoscopic procedures * Scheduled for procedures that require Trendelenburg or anti-Trendelenburg positioning * Neurological disorders * Glaucoma * History of bilateral eye related trauma * Intellectual disability