The Trifocal Lens-meaning they have three focal views-is designed similar to bifocal lens with exception to center focal point on lens is for intermediate vision.

The fourth type of lens is Multi Focal lens. It has more than one focal view; therefore a Bifocal and a Trifocal are types of multi focal lenses.

Other types of lenses that are specially designed for other purposes include Computer Lens. They are designed so that when sitting at a computer, a person can view monitor and papers nest to monitor at same time. And then there are Double Bifocals, which are rarely prescribed, but when they are it is usually for pilots, electricians or other professions that need to have close vision overhead.

Benjamin Franklin is credited for invention of bifocal lens. With a bifocal lens bottom half is used for reading and top half is for seeing objects that re further in distance.

The first lenses in prescription eyeglasses were made from quartz crystal and very low in quality and durability. Then in early 1900's, Bausch and Lomb created glass lens. Today most prescription eyeglasses are made from a plastic material that can be polished and tinted like glass lenses. The advantage to plastic lens is lighter weight of prescription eyeglasses as well as durability is greatly increased.