Spectacle glass, also known as eyeglasses or glasses, are a type of corrective lenses used to correct vision problems. They consist of two curved lenses made of glass or plastic, held in place by a frame that rests on the nose and ears. The lenses are usually made of a material called CR-39, which is a lightweight plastic that is highly resistant to scratches. LENS is the four letter solution for the term SPECTACLE GLASS.