Types of Spherical Lenses Definition: A piece of a transparent medium bounded by at least one spherical surface, is called a spherical lens. An optical lens is made of transparent material such as glass or clear plastic. One or both surfaces usually have a spherical curve. There are two types of lenses, converging and diverging lenses. A converging lens is called a convex … [Read more...] about What are the Types of Spherical Lenses