Repeated experience has shown that the eye closes so quickly that where the lens is broken and pieces of glass fly from it, the eye-lid is almost invariably shut; if any cut is received it is on the outside of the lid, and superficial in character. The goggles "give" somewhat under the impact of a blow, and the fraction of a second's time thus saved is sufficient to close the eye-lid and save the eye. Where the force of a flying chip is so great as to break a heavy lens of this kind, it is obvious that the eye-ball would be shattered, even though the eye-lid were closed, if no goggle were used.
At a recent safety exposition one of the goggle manufacturers gave a graphic demonstration of the resistive power of good lenses. Repeated blows from a plunger actuated by a strong spring often failed to even crack the glass. Many workmen have been reassured in this way, where they were at first afraid to wear goggles lest they should get particles of broken glass in their eyes.
-- David Stewart Beyer, Industrial Accident Prevention (Boston: Houghton Mifflin, 1916), 373-4.