The ORBEYE surgical microscope is an FDA-cleared apparatus designed to facilitate operating procedures that involve fine nerves, blood vessels, and other small anatomic features by providing an enlarged stereoscopic visual field of the surgical site. The 4K 3D digital images of the ORBEYE microscope provide high-resolution stereoscopic images of the fine structures of tissue and blood vessels. As the surgical procedures are displayed on a large 55-inch monitor, the device is expected to reduce fatigue of the operator by eliminating the need for extensive viewing via microscope eyepieces for an extended period of time. The technology adopted in the ORBEYE was developed by Sony Olympus Medical Solutions, and its product design was handled by Olympus Medical Systems Corp. The ORBEYE is marketed by the Olympus Corporation.

6 tissue samples will be obtained intraoperatively for each patient and assessed for 5-ALA visualization (strongly positive.weakly positive/negative). Tissue samples will be submitted for pathological assessment to determine whether tumor cells are present or absent. Visualization results will be evaluated against the pathology results (gold standard) to determine the sensitivity, specificity, positive predictive value and negative predictive value for 5-ALA visualizations with use of the ORBEYE system.

Residual tumor volume will be identified in post surgical MRI scans. Extent of resection will be compared to preoperative MRI scans.

Surgeons will complete a questionnaire after each surgery to assess the visual experience of using the ORBEYE during the surgical procedure. The questionnaire asks about the superiority of the ORBEYE system compared to conventional binocular microscope, using a scale of 1-5, 1 being strongly agree and 5 being strongly disagree.