Postural discomfort and the consequent aches and pains result from the effort to view the monitor when it is set at the wrong place in relation to the operator's position. Two factors come into play: viewing angle and viewing distance. Viewing angle refers to the degree above or below an imaginary horizontal line at the level of the viewer's eyes and the centre of the object being looked at; in case of a computer work it is the centre of the screen (see Figure 1). Viewing distance refers to the space between the operator's eyes and the screen (see Figure 1). A poor angle leads to postural (neck and shoulders) discomfort, while the wrong distance can contribute to eyestrain.

当显示器设置在相对于操作员位置错误的位置时，由于费力查看显示器而导致姿势不适以及随之而来的疼痛。 有两个因素发挥作用：视角和观看距离。 视角是指观察者眼睛与被观察物体中心的假想水平线上方或下方的角度； 对于计算机工作，它是屏幕的中心（参见图 1）。 观看距离是指操作者眼睛与屏幕之间的距离（见图1）。 角度不佳会导致姿势（颈部和肩部）不适，而错误的距离会导致眼睛疲劳。

Figure 1

The existing guidelines and recommendations on both viewing angle and particularly on viewing distance differ, sometimes significantly from one another. For this reason they should not be taken as a commandment "carved in stone" but merely as guidelines. As such, they can be used as a starting point for tailoring any given situation.

现有的关于视角和尤其是观看距离的指南和建议有所不同，有时甚至彼此之间存在很大差异。 因此，它们不应被视为“刻在石头上”的诫命，而应仅被视为指导方针。 因此，它们可以用作定制任何给定情况的起点。