Contact Lens Materials: Their Properties and Chemistries

Abstract

The use of poly(methyl methacrylate) (PMMA) in corneal contact lenses led to the popularization of the contact lens in the early 1950s. PMMA is lighter than glass, clear, rigid, and relatively inert biologically. Its largest failing as a contact lens material is its lack of oxygen permeability, and a variety of materials have since been developed to overcome the oxygen deprivation problem that arises with PMMA lenses. More modern contact lens materials have much higher oxygen permeability than PMMA, and most of these materials fall into one of two categories: (1) soft hydrogels, or (2) rigid gas permeable. The chemical compositions and physical properties of both types of materials will be discussed.