CR-39 lenses and polycarbonate lenses are two main types of lenses widely used worldwide. But people may not know much about their features and their differences. The following will give some introduction on these two kinds of lenses and their differences in the hope that people can choose the suitable lenses they need.

What is CR-39? CR-39 is an optical degree for plastic polymer which is measured by the light weight, chemical resistance properties and tint-ability. Polycarbonate lenses are characterized by strong impact resistant ability, which has been widely used in recent years. The main differences lies in CR-39 and polycarbonate lenses are as following:

From the impact resistance aspect, CR-39 is not as strong as polycarbonate lenses. It is researched polycarbonate lenses can have ten times of impact resistant ability than normal plastics. So when people take some active sports, it is advised to wear polycarbonate lenses instead of CR-39 lenses. However, CR-39 is more scratch resistant than polycarbonate. But please note it does not mean CR-39 will not scratch, if not taken good care of, they will also scratch. And in order to have good scratch resistance, polycarbonate can also have some scratch-resistant coatings.

Though polycarbonate lenses are more impact resistant, but they can also be broken. The good point is when they are broken, they will be broken into big pieces. While for GR039 lenses, they will be broken into small pieces. Therefore, in this aspect, polycarbonate lenses are safer to wear compared with CR-39 lenses. What’s more, polycarbonate lenses are thinner than CR-39 lenses and they usually have a lighter weight, which enable them comfortable to wear.

With the rapid development of lenses technology and people’s knowledge about lenses and health increasing, people are desired to have lenses which also have UV protection ability. If you also have this kind of requirement, let me tell you that it is not hard to realize. Take polycarbonate lenses as an example, they can offer UV protection, and can stop 99.9% rays not only from sun, but also from fluorescent lights and even computer screens. So they can offer you the protection you need.

From the above introduction, we can see polycarbonate lenses are impact resistant, UV protection, and thinner and comfortable to wear, while CR-39 lenses are scratch resistant and have more choices for coatings and tints. Therefore, after you learning about this, I am sure you can choose the suitable lenses according to your requirement.

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Since its creation in 1970s, polycarbonate has been widely used in aerospace applications, helmet visors of astronauts and space shuttle windshields. Today, this material has been the standard for safety glasses, sports glasses and children’s eyeglasses. Polycarbonate lenses are thinner, lighter and 10 times more impact-resistant than traditional plastic lenses.

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 uses 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 also has similar features of polycarbonate is Trivex. Using cast-molded manner, Trivex lenses provide crisper vision and have become a major rival of polycarbonate lenses.

Polycarbonate lenses also feature 100% UV protection resistance, without the help from UV treatment. While polycarbonate lenses are extremely impact resistant, it is also relatively soft, which means they can absorb energy. This feature of the material makes polycarbonate lenses fragile 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.

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 broke 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.