The Mandelbaum effect is the tendency for the eye to focus nearby in conditions of poor visibility.
[1] Because dirty glass can aggravate the effect, potentially causing a pilot or driver to miss seeing an obstacle or hazard, it is a strong safety argument for keeping windows clean.
A common synonym for the effect in FAA[4] and Transport Canada[5] usage is "empty-field myopia."
[3] As in the aviation condition known as spatial disorientation, it is posited that some people are severely affected by the effect, some mildly, and some not at all.
[6] In aviation and automobile safety research, the Mandelbaum effect is a useful tool in determining bias in stressful conditions.