The most common types of appliance are eyeglasses and contact lenses.
History shows that eyeglasses have been around for hundreds of years.
Modern innovations have improved this technology. The bifocals, invented by Benjamin Franklin in the 18th century was a major improvement to the science. Today we have special plastics and coatings to further improve the optics of glasses and frame design has become so fashionable as to lead certain celebrities to wear them regardless of their vision. Glasses are an elegant solution to the problem of vision correction. They offer a safe, established therapy of correction, with simple design, maintenance and use.