The lack of depth perception and the sense of distance with 2-D video displays are drawback for endoscopic surgery. A stereoscopic 3-D endoscope and a BiVIS (Binocular Vision by Image Shifting) endoscope have been developed to solve these problems. We compared conventional 2-D, 3-D and BiVIS endoscopes in terms of performance for depth perception, manipulation and sensory scores of a three-dimensional effect. Although the BiVIS display system did not show superiority in depth perception and sense of distance, the result, indicated that it gave operators a stronger sensation of depth and rea...