Why do people wear protective equipment? So that they eye doesn't get slashed by a force of nature they're working with, say, a wild animal like a bear or an explosive chemical reaction. Better be safe than sorry!
(This kanji is usually used to mean "wear" from the shoulders down, so it excludes various form of facewear and eye protection, however you can imagine a full-body kevlar-reinforced body suit that would also cover your face.)