Ion exchange tempering of glass ophthalmic lenses.
We performed low velocity drop-ball tests using 5/8-, 7/8-, and 1-inch diameter steel balls on ophthalmic crown glass lenses chemically tempered by the ion exchange process. Four representative dioptric strengths (+ 2.50 spherical, - 2.50 spherical, -2.50 cylindrical, and plano) were studied with the isolated lenses mounted, convex side up, on the American National Standards Institute Z80 test block. New ion exchange lenses exhibited a 100 to 350% greater capacity for attenuation of energy from low velocity, large size missiles than matched lenses of similar strength prepared by the conventional heat-treating and air-quenching process.
D005131:Eye Injuries / Q000517:prevention & control; D005139:Eyeglasses / Q000592:standards*; D005898:Glass; D006801:Humans; D007474:Ion Exchange; D013314:Stress, Mechanical