EMPTY VISUAL FIELD MYOPIA

When the eyes have nothing to focus on (e.g. at night or in low visibility conditions), they naturally focus at a distance of one to two meters in front of you. This is not a standard distance and it differs between individuals. The result is that if a distant target appears, the eyes will not be 'triggered' to detect it since they are staring at a short distance in front of them. This phenomenon occurs when there is a cloudless sky and all you see is blue, when there is an overcast sky and everything is white or when flying the night in total darkness where everything is black. In all these cases the eyes have nothing to focus on and they relax, focusing to a distance of one to two meters in front of them.

Hyperopia → long-sightedness, where distant objects are seen more clearly than near ones.
Autokinesis → an illusion where a stationary light appears to move in darkness when stared at for a long time
Empty field myopia → the eye naturally relaxes and focuses at a short distance (about 1–2 metres) in lack of visual cues
Presbyopia → age-related condition where the eye loses the ability to focus on near objects