What lens materials are available?
Glass lenses used to be the norm, but in light of technological advances over the years, glass isn’t as widely used anymore. While glass lenses can have excellent optical qualities, they can break easily and are often quite expensive.
Instead, most lenses are made using special types of plastic, which are typically lightweight and stronger. There are a number of different types available, which can depend on your individual needs, which include CR-39, polycarbonate and high-index plastic lenses.
Which material is best for lenses?
CR-39 is a type of thermal-cured plastic polymer and was first introduced in the 1940s. It weighs half the weight of glass, without compromising on optical qualities, and it has become the standard for everyday lenses ever since.
By the 1970s, polycarbonate was introduced in the lens manufacturing industry, particularly for children’s eyewear, sports glasses and safety applications like helmet visors and goggles. Polycarbonate is extremely impact-resistant and even lighter than its predecessor, CR-39. Additionally, polycarbonate lenses are able to block 100% of UV light.
If you have a strong prescription, you will likely be recommended high-index plastic lenses, which allow you to achieve the level of correction you need without having to wear thick lenses. High-index plastic lenses are able to bend light more efficiently than regular lenses, so less material is needed in order to achieve the right correction. This is known as a higher refractive index.
Why is the lens material important?
In most cases, your lifestyle can help you to choose the right lens material to suit your needs. It’s important to consider which material will be best suited to your everyday activities. For example, if you are looking for children’s lenses or lenses to wear when playing a sport, polycarbonate could be beneficial as it is less likely to break. This can prevent any injuries or accidents, as well as making sure visual acuity isn’t compromised.
Similarly, if you are hoping to choose a frame without rims, polycarbonate lenses are often recommended for maintaining the strength and durability of the overall lens solution.
If you need new lenses and are due for an eye examination, don’t forget to ask your optician about the lens material that is most suited to your needs.