No its not standard if thats what you meant to say.

My thoughts were more from a martial art point of view originally, cause you have the whole in vision feet and hands when you look there and if you stop them near the joints on each limb you have their balance as well.

I did notice that when boxers are fighting in close nose to nose they cant always look into the eyes anymore too.

It all just got me thinking is all.

Theres alot to it and I think distances are the key factor and the rules of engagement will play a big factor. (you dont want to be eyes down if head butts are on). and you dont want to caught by an axe kick or one to the nuts when moving in cause your looking into eyes etiher.

Into the eyes pre contact range and at leg or arms length seems usual and sensible what ever the art form though.