Features of polycarbonate lenses

Since its creation in 1970s, polycarbonate has been widely used in aerospace applications, helmet visors of astronauts and space shuttle windshields. Polycarbonate lenses are thinner, lighter and 10 times more impact-resistant than traditional plastic lenses. In addition, polycarbonate lenses can offer 100% UV protection from harmful sun rays. Today, this material has been the standard for safety glasses, sports glasses and children’s eyeglasses. It is also one of the most popular lens materials in the whole eyewear industry. What is more, these features position polycarbonates between commodity plastic and engineering plastic.

Inherent UV protection

Polycarbonate lenses feature 100% UV protection, eliminating the need of additional UV treatment on the lenses. Polycarbonate has the unique optical feature called inherent UV protection. In some cases, it is also called a built-in capability. This means that customers choosing polycarbonate lenses no longer need to make an additional investment in a UV lens coating. While polycarbonate lenses are extremely impact resistant, it is also relatively soft, which means that they can absorb energy. This feature of the material makes polycarbonate lenses easily vulnerable to scratches. As a result, scratch-resistant coatings are needed for polycarbonate lenses to provide necessary scratch protection. These scratch-resistant coatings enhance the hardness of polycarbonate lenses.

Impact resistance

Another precious property of polycarbonate lenses is that they are not brittle. Even attacked by speeding objects such as balls or racquets, polycarbonate lenses will not break due to their ability to hold up under impact. When it comes to regular plastic lenses, fast-moving objects can easily break the lens and hurt the eye. Thanks to this protective feature, polycarbonate lenses have become the first choice for children’s eyeglasses, sports goggles and safety glasses.

During dangerous sports, impact-resistant frames are also necessary to match polycarbonate lenses, since the frames are still essential to hold the lenses. Simple polycarbonate lenses can not provide enough resistance against high impact. In this case, polycarbonate lenses on ordinary frames are not safe. Actually, polycarbonate lenses are recommended for all types of children’s eyeglasses. In addition to extreme impact resistance, children can also benefit much from the other properties, like natural UV protection, lightness and thinness.

Polycarbonate production

Polycarbonate lenses are made in a way that is quite different from that of regular plastic lenses. Conventional plastic lenses are made from a cast molding process. The production of a polycarbonate lens involves an injection molding process, during which small pellets will be heated into liquid polycarbonate. Further steps include liquid polycarbonate injection and high-pressure compression. Another lens material that has similar features of polycarbonate is Trivex. Using cast-molded manner, Trivex lenses provide acute vision and have become a major rival of polycarbonate lenses.

Polycarbonates VS high index plastic lenses

In terms of lightness and thinness, polycarbonate lenses are as competitive as high index lenses. But when it comes to scratch resistance, polycarbonate lenses are relatively inferior, which explains the necessity of applying a scratch-resistant coating. Yet another problem is that it is more difficult to coat or tint polycarbonate lenses, which makes the application of scratch resistant coating a tough task. In addition, polycarbonate lenses are more frequently linked with visual aberrations and distortions.