Materials for occupational eye protectors

The selection of lens materials for non-prescription personal protective equipment has been a relatively simple process and has its origins in many studies around the 1970s. The viable materials available at that time were tempered glass, hard resin (n = 1.50) and polycarbonate. The modern spectacle non-prescription eye protector of choice is inevitably hard coated polycarbonate, which has exemplary impact resistant properties. In the prescription lens area, there is a bewildering array of materials of various refractive indices with a variety of coatings. The selection of an ophthalmic lens has optical and cosmetic considerations ahead of impact resistance. In complying with the Australian/New Zealand standard on prescription eye protection, adequate impact resistance must rate as the foremost requirement, with optical and cosmetic considerations as important but lesser considerations. In this review, the evidence on impact resistance of the available materials is presented, the standards set for testing impact resistance are detailed and some guidance is provided for the selection of prescription eye protection materials.