Effect of Auto-Erased Sketch Cue in Multiuser Surgical Planning Virtual Reality Collaboration System

Many researchers have introduced Virtual Reality (VR) systems for various medical applications. One of the typical applications is a medical collaboration system that helps users collaborate in a virtual reality environment while physically staying in different places. In this research, we explore the effect of the using 3-second sketch communication cue in a collaborative VR system for two surgeons planning surgery, when a head-gaze pointer and hand-gesture are available as the baseline communication cues. We conducted a user study comparing four conditions according to the availability of the auto-erased sketch cue by two collaborators: the message provider and receiver. The results demonstrated the benefits of the 3-second sketch communication cue that increased the level of usability and message understanding between two collaborators and decreased the required task load. We additionally found that the sketch cue would be more beneficial if it was erased after finishing each collaborator’s communication turn rather than after three seconds. With the lesson learned from the user study, we propose six design principles for the multiuser planning surgery VR system: 1) 3D reconstructed body model should be supported, 2) the cross-sectional view at any angle and position should be supported, 3) visual communication cues, such as sketches, pointers, and hand gestures, are crucial for communication, 4) the erasing sketch should occur when the next sketch starts being drawn 5) the system should support permanent annotations, 6) the system should control the transparency of the hand gestures and head-gaze pointers to mitigate the effect of occlusions.