Endoscopic third ventriculostomy is a minimally invasive technique to treat hydrocephalus, which is a condition in which the patient is retaining excessive amount of cerebrospinal fluid in the head. While this surgical procedure is fairly routine, it carries some risks, mainly associated with the lack of depth perception, since monocular endoscopes provide only 2D views. We studied the advantages given by a 3D stereoendoscope over a 2D monocular endoscope, first by assessing the variability of stereoacuity in each subject, then in analyzing their overall correct response rate in differentiating between heights of two different images with 2D and 3D vision.