Under extreme stress our vision can be impaired from the usual broad vision (peripheral vision), to the phenomena called tunnel vision(one of many different vision problems created by stress), were your visual focus is strongly reduced.

On a daily basis we don’t think about that our peripheral sight gives us a vision area of about 180 degrees, given us a very good overview of our surroundings. This enables us to be able to see threats in a broad view. Using this quality helps in different situations like driving a car and a bike suddenly appears on the road or a car tries to pass(and you didn’t notice it in your mirror). The peripheral vision works a bit like a radar triggering your attention to things coming into sight, thus triggering us to move our focus to what is on its way.

If the threat triggers our fight/flight hormones, this can influence our sight by concentrating it 100% on the threat itself. The advantage of this is that our whole being is focused(tunnel vision) on solving this problem(threat), and keeping this focus as long as the threat is a reality.

A disadvantage with tunnel vision is when your focus is needed to handle different tasks or opponents, because you are preoccupied by your dominated threat.

Stress impaired vision like tunnel vision will vary from person to person, depending on stress level and how well they cope with stress and impaired vision. There is no doubt that by working with scenario based training, and learning how to learn and cope with impaired vision will help in a physical confrontation were your life is at stake.