Good question. I have never had to stop a charging animal and hope I never do. However, I do shoot with both eyes open - even with a telescopic sight. On a moving target (which I have shot quite a bit with a rifle) doing so provides constant subconscious depth perception which is essential in judging range and relative angle of movement. I "see" the sight (telescopic, ghost ring and front bead, or blade and bead) while also being aware of the target with both eyes. I suspect that would be useful in a charge, and I know it is in combat or in shooting dynamic competitive targets like running boar. All that works best if the rifle fits well and aligns itself on coming to the shoulder.