Prescription Lenses are available in Glass, Plastic CR39, & Polycarbonate materials. We strongly recommend the use of Polycarbonate Lens for safety eyewear. Polycarbonate is the most impact resistant lens material available in the market today & offers significantly greater impact resistance than Glass or Plastic CS-39 lenses.
Polycarbonate material is manufactured differently from the way that other lens materials are fabricated. An enormous amount of pressure is used to compress the raw material. The resulting product holds up so well under impact not because it is hard and unyielding, but rather because it is flexible and gives slightly under pressure without breaking. Polycarbonate lenses are actually constructed out of material that is identical to what is called “bulletproof glass.” Polycarbonate has also been used for astronaut helmet shields and space shuttle windshields.
Features & Benefits:
High Impact Resistance – Studies have been made detailing exactly what happens when an object traveling at high speed meets a polycarbonate lens versus a traditional plastic lens. Using film that is slowed down and viewed frame by frame, one investigation demonstrated that a fast-moving ball coming into contact with a plastic lens broke the lens and impacted the eye. In contrast, the same ball traveling at the same rate of speed impacted the polycarbonate lens and flexed the lens but did not break it.
Lightweight – 1/2 the weight of conventional glass lenses; up to 30% lighter than Plastic CR39. In fact, polycarbonate lenses are sometimes referred to as featherweight lenses.
Ultraviolet (UV) Protection – A built-in UV block that won’t rub or wear off. Protective wearer’s eyes from more than 99% of harmful UV rays.
Scratch Resistance – The flexibility or softness of the lens material dictates that a scratch resistant coating be applied to the front and back surfaces of polycarbonate lenses. Manufacturers automatically coat them, and fabrication laboratories add a scratch resistant coating to any uncoated lens surface before sending the lens to a dispenser. So any polycarbonate lens you buy already has built-in scratch resistance.