When I drew on my KS buck, I saw everything - like looking into a wide open field, and had to refocus on whatever spot it was I picked the arrow to go.
I don't remember if the deer stopped, if he looked up, away, down .... I don't remember anything he did once I regained my focus
Now that said, i think some people have better vision than others, allowing them to pick solitary hairs. I can't if its very far away, so instead I focus on lights/darks - and that pocket right behind the shoulder nearly always is darker, and the nook right in behind the darkest.
Probably sounds weird ....