Green Tone Night Vision

When one uses night vision goggles, he finds that there is a greenish tone to see things. This is done purposefully because we humans have an uncanny ability to distinguish between different tones of green.

This is done with the purpose to aid humans in recognizing objects which are further away since night vision goggles use different tones to show different depth in objects. If a tone was different that green, say red for example; this would be extremely hard - not to mention harmful to the eyes! Green is a color that we have much resistance to (opposed to warm colors such as red or orange).