The VE capability of standard desktop displays can be enhanced by presenting separate images to the left and the right eyes, thus enabling a stereoscopic view just as we have in the real world. This can be accomplished in a variety of ways (Slocum et al., 2007). One is to add a polarizing panel to the desktop monitor and to have the user wear polarized glasses, producing what is known as passive stereo. A second approach is to cycle left- and right-eye views on the display, and have the user wear shutter glasses that are in sync with the display, this is known as active stereo. A third approach is to use an autostereoscopic display in which no specialized glasses are required (Dodgson 2005). Although autostereoscopic displays sound ideal, they are more expensive and are characterized by a limited number of viewing angles known as "sweet spots".