Why is eye protection non-negotiable?

Pellets and especially BBs can fragment, deflect off hard surfaces, or come straight back at the shooter from steel targets and pellet traps.

A ricocheting BB easily retains enough energy to penetrate an eye. Even seasoned shooters take fragments to the face. ANSI Z87.1-rated safety glasses or shooting glasses are cheap insurance and should be worn by the shooter and anyone within 20 feet of the firing line, every time, no exceptions.