Optical properties of lens materials

In the third in our short series on dispensing matters,
Dr Keziah Petre outlines the optical properties of lens materials and their influence on use in spectacles. CET module C1379

When dispensing a patient with a pair of glasses there are many considerations to take into account. Will the lens type be single vision or multifocal? Will the form be spherical or aspheric? Will the lenses be tinted? What is the best lens material for this patient? The purpose of this article is to address the last of these questions by reviewing the main properties of a spectacle lens that are affected by the choice of lens material. These will be compared across the three basic categories of material: glass, plastic and polycarbonate.