Stereoscopic displays can simulate the perception of depth information, potentially increasing human distance perception in remote viewing scenarios such as those involved in robotic tele-operation. However, distance perception is a complex perceptual task that is not yet fully understood. Two current research issues are how different stereoscopic displays and viewing heights affect egocentric distance perception. This paper describes an experiment conducted to investigate these issues. It compared distance perception in a real environment with that in identical visual scenes observed through an HMD and 3D Stereo Display. Other parameters, notably field of view, were tightly controlled. Motivated by fact that many tele-operation scenarios involve near ground viewing positions (due to the fact that many robots are small), the study also explored the impact of viewing height (at 20 cm and 110 cm) on distance perception. Results indicated substantial under-estimation of distance across all conditions. Interesting, low eye-height led to a significant reduction in the level of underestimation in the HMD and 3D Stereo Display, a variation that may be due to changes in the perceived height of the horizon in the real world 20 cm viewing height condition, compared to the fixed height of the perceived horizon in the videos shown on the HMD and 3D Stereo Display.