Glass lenses (with and without vinyl Fresnel optical membranes pressed onto the back surface) were impacted by dropped and ballistically-fired steel balls. High speed cinematography of fracturing showed that regardless of fracture resistance (which was not altered by the membrane), glass fragments were splintered off the back lens surface or were driven through the lens. The membrane either prevented back-surface emission of lens particles or contained the fragments in their travel toward the eye-plane, thereby reducing the danger of ocular injury from broken spectacle lenses.