A refracting device is an optical instrument that uses the bending of light to create an image. The two most common refracting devices are prisms and lenses. A PRISM is a transparent optical element with flat, polished surfaces that refract light. A LENS is a curved piece of transparent material that refracts light in order to form an image. Both prisms and lenses are used in a variety of applications, such as microscopes, telescopes, cameras, and eyeglasses.