430 ILCS 110/1
No person shall distribute or sell any eyeglasses or sunglasses unless the eyeglasses or sunglasses are fitted with impact resistant lenses, except in those cases where the physician or optometrist, having found that such lenses will not fulfill the visual requirements of the particular patient, directs in writing the use of other lenses and gives written notification thereof to the patient. Before they are mounted in frames, all lenses shall be capable of withstanding an impact test of a 5/8 inch steel ball dropped 50 inches. This test is to be conducted at room temperature with the lens supported by a plastic tube (one inch inside diameter and 1 1/4 inches outside diameter) with a 1/8 inch x 1/8 inch neoprene gasket on the top edge.
430 ILCS 110/1