Final answer:
Face shields are considered secondary protection and should always be used in combination with safety glasses or goggles.
Step-by-step explanation:
Face shields are considered secondary protection and should always be used in combination with safety glasses or goggles. While face shields provide a barrier for the entire face, they do not provide adequate protection for the eyes alone. Safety glasses or goggles are designed specifically to protect the eyes from potential hazards such as flying debris or chemicals.