Choosing The Ideal Lenses For Your Eyeglasses
How to choose the right lenses for your new eco eyeglasses
CR39 or High Index?
Choosing lenses for your spectacles can be the most daunting thing about buying eyeglasses online. However it's one of the most important, as the quality of the lenses will determine how happy you are with your purchase.
As an eco-friendly eyewear brand, focusing on reduced plastic and using sustainable materials, we’re often asked if we can do Glass lenses, or even accused of hypocrisy for using plastic lenses. This lens buying guide will outline the different materials used for lenses and hopefully answer some common questions that may otherwise hold you back from your new shiny eco-eyewear.
Materials used for Eyeglasses Lenses
There are traditionally four different types of eyeglass lenses widely available on the market; Glass, CR39 Plastic, Polycarbonate and High Index.
Each has their benefits and drawbacks, which we have summarised here.
Glass Lenses (AKA: Mineral)
Glass lenses were the traditional material used, typically before the 1930s. The benefits were exceptional optic performance, and an arguably a more eco-friendly production;
Glass is a naturally occurring material, however does take a lot of energy to produce. The downsides, however made glass almost obsolete in the industry. It’s a heavy material, so will need thicker frames to hold them; reducing comfort and style choice.
In addition, glass broke easily - one drop on the pavement and it’s another trip to the opticians!
For Fresh for Pandas frames, we do not use glass as most of our frames are wood based. Wood has a natural ‘give’ to it, engineering wise, the rigidity of glass doesn’t bode well, as well as the heavier aspect will give more pressure to the ultra lightness of the frame.
CR39 Lenses / Plastic Lenses
CR39 is a type of plastic developed in the 1930’s which revolutionised the eyewear industry. As it weighs around half of what glass does, low cost and high performing optics, made CR39 material the industry standard for day to day spectacle use.
CR stands for Colombia Resin, the 39 was merely the final iteration of the formula that is still used today.
For eyeglasses, CR39 offer great scratch resistance, and ideal for occasional use to day to day use. They can be coated for specific use to increase UV protection, block blue light or reduce glare. Fresh for Pandas offer eyeglasses with CR39 lenses, with the option to increase UV protection, blue light protection or specialised coating for reducing glare whilst driving.
The downside to CR39 lenses is that they are thicker than other materials. Therefore, for eyeglasses, it’s only recommended to use CR39 lenses for lower prescriptions. We recommend any prescription with a strength higher/lower than +3/-3 to avoid CR39 lenses; as the lens may overlap the frame, or the frame may not be able to accommodate them.
PC lenses were developed in the 1970s and is considered an upgrade to CR39 lenses. It’s lighter in weight than CR39, but it’s main attribute is its strength and impact resistance.
It’s used for bulletproof glass, safety equipment and fighter pilot screens. In the eyewear industry, Polycarbonate is ideal for sports eyewear, children's eyewear and protective/safety googles.
High Index Lenses
High Index Lenses answer the thickness problem of CR39, and are therefore suitable for all types of prescriptions. High Index refers to how efficiently the material refracts light. The higher the index, the slower the light moves through it.
This enables less material to be used to bend the light than PC or CR39 lenses. The result? Thinner lenses, meaning a better look, lighter lens and more comfortable wearing experience.
Fresh for Pandas High Index Lenses come with UV protection, anti-scratch properties and anti-reflective properties as standard, and can come with blue light protection, extra UV protection, or speciality lenses designed for reducing glare during driving.
Fresh for Pandas Eyewear - Lens Options
High Quality Lenses, Premium Coatings, Eco-Friendly Frame
Our frames are typically used for day to day usage as an eco alternative to mass-produced metal or plastic frames. Wood, bio-plastic and titanium are used to ensure a biodegradable product, backed by sustainable manufacture.
Our customers typically use our frames in the office, at home or for driving. Due to the nature of wood we wouldn’t recommend our frames for sports activities, or for use in industrial environments such as factories or building sites.
For this reason, we have chosen to only offer CR39 lenses as a budget option, or High Index lenses for everything else.
Our lens options should cover the majority of use cases, however we are able to further customise your lens options, materials or prescription requirements to order. Just drop us an email with your requirements and we can arrange a specialised quote.
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