Depth perception in laparoscopy through perception-action coupling

Laparoscopic surgery has considerable advantages for the patient over conventional surgery; for the surgeon, however, it has mostly disadvantages. One of the main problems is that the coupling between action and perception is hampered, i.e. the surgeon has no direct control over the laparoscope since it is held and directed by an assistant. In two experiments we explored how action-perception coupling can be restored. In the first experiment we explored the possibility of restoring action-perception coupling by providing the surgeon with direct control over his visual information. The applicability of two principles were explored: viewpoint movement parallax, where the surgeon controls the change in the point of observation (the laparoscope) directly with his head movement; and shadow movement parallax, where the surgeon controls the change in the point of illumination directly with his head movements. In a second experiment we investigated whether the performance of a surgeon is influenced by motions of the laparoscope that are not generated by the surgeon himself, but by the assistant directing the laparoscope. We concluded that restoring the action-perception coupling (i.e. providing the surgeon with direct control over the laparoscope's motions) improves the surgeon's ability to perform explorative, as well as manipulative, tasks. We also concluded that, as disturbances of laparoscope movements hamper the surgeon during manipulation, the laparoscope should be supported by a mechanical support.