If you require lenses to correct a vision problem, it’s important to choose the right lenses for your spectacles. Your choice of spectacle lens material and design can impact factors such as appearance, comfort, vision and safety. There are many different types of lens materials as well as additional features such as lens coatings, which can make your choice a difficult one.
There are a number of thin and light lenses that could have benefits for your vision as well as comfort. Thin and light lenses can be beneficial for those who require a high prescription, as well as improving the appearance and comfort of your glasses, making them a great choice for your next pair of lenses.
Different lens materials for thin and light lenses
Over the last 20 years or so, there has been an increased demand for thin and light lenses that are stylish as well as practical. There have been a number of thin and light lenses created over the years to suit the different vision and lifestyle needs, each with its own features and benefits.
In the early 1940s, CR-39 plastic lenses were introduced. Created from a thermal-cured plastic polymer, they became popular due to their low cost and lightweight construction. CR-39 is about half the weight of glass, without compromising on optical qualities.
By the 1970s, the use of polycarbonate was introduced, primarily used for helmet visors. Polycarbonate was first used to create bulletproof-type glass for banks and other similar safety applications, before being used in the likes of children’s eyewear, sports glasses and safety glasses. Polycarbonate is even lighter than CR-39 and more impact-resistant.
Polycarbonate lenses have become the standard for safety glasses. As polycarbonate is less likely to break compared to regular plastic lenses, it is often a favoured material for rimless eyewear designs. Polycarbonate lenses will also block 100% of UV light.
Polycarbonate lenses are available in a variety of lens designs, whether you require single vision lenses, varifocals or something more unique such as photochromic lenses.
High-index plastic lenses
High-index lenses are usually recommended if you have a strong prescription for myopia, hypermetropia or astigmatism. However, they can also make your spectacles much thinner and lighter, regardless of your prescription.
If you are short-sighted, your corrective lens will be thin in the centre and thicker at the edges. The stronger your prescription, the thicker the edges will be, which can make them more noticeable and may take away from the appearance of your eyewear.
High-index plastic lenses can bend the light more efficiently than regular lenses, meaning less material is required to correct the same level of refractive error. This is known as a higher refractive index, and results in thinner and lighter lenses, making them much more attractive and comfortable to wear.
Your optician can help you to understand the different high-index lenses available, and which are best suited to your needs.
In the early days of lenses, they were all made of glass. Glass lenses have excellent optical qualities and can have a high scratch-resistance. Despite this, glass lenses are not widely used because they can break very easily, as well as being heavy and expensive.
Next time you visit your optician, don’t forget to think about the importance of the lens material as well as choosing a stylish frame.