Depth Perception and Indirect Viewing: Reflections on Minimally Invasive Surgery
Anthony H. Reinhardt-Rutland, Judith M. Annett, Mervyn Gifford · International Journal of Cognitive Ergonomics · 1999
In minimally invasive surgery, a camera conveys the site of operation to a TV monitor. This imposes severe restrictions on depth perception of the site of operation. The present review shows that depth perception must rely mainly on pictorial information, perhaps with enhancement of the occlusion cue by motion, although motion information such as motion parallax is not likely to be important. The effectiveness of pictorial information is diminished by competition with binocular and monocular information conveying the flatness of the monitor's screen and by difficulties in scaling: Only a degree of relative depth can be conveyed. Furthermore, pictorial information can be misleading. Stereoscopic viewing systems are being developed to introduce binocular information to minimally invasive surgery. However, stereoscopic viewing is problematic because binocular disparity conflicts with convergence and monocular information. Also, perception of brightness may be affected, which may influence pictorial depth perception. A more radical alternative approach to improving depth perception in minimally invasive surgery may reside in individuals lacking binocular function: There is much redundancy in depth information, and such individuals seem to compensate for their lack of binocular function.