Sunglasses Lens Materials
The material of your sunglasses lens is an important feature you should consider while shopping for sunglasses. Not only will it determine the resistance of the lens, but it will also give you better vision.
This is what you need to know:
- Glass lenses have unmatched quality, but will be the most expensive material for your sunglasses. Glass is also heavier and will shatter if broken. Even though glass lenses are quality-wise the best choice, they are not suitable for all activities.
- CR39 (Plastic) is thinner, cheaper and weighs half as much as glass, and it is the widest used material for general purposes sunglasses today. CR39 offers very good optical performance even for high prescriptions. Besides, it has good scratch resistance due to a hard layer.
- Polycarbonate lens sunglasses are lighter, though this material doesn’t provide the exceptional optics of glass lenses. Polycarbonate is up to 10 times more impact-resistant than plastic or glass lenses and it provides 100% protection from the sun's harmful UV rays.
- We advise you to stay away from acrylic lenses, unless you are prepared to buy new ones quite often. They are the least durable and optically clear. On top of that, when exposed to heat they tend to warp. Acrylic is known for being affordable, but it also degenerates quickly.
| CR-39 | Polycarbonate | Glass | |
|---|---|---|---|
| Optical quality | Good | Good | Very good |
| Weight | Standard | Light | Rather heavy |
| Thickness | Standard | Thin | Thick |
| UV protection | Very good | Very good | Very good |
| Scratch resistance | Good | Very good | Very good |
| Impact resistance | Can shatter | Doesn't shatter | Heavily shatters |
| Price | Inexpensive | Standard | Rather expensive |
These values apply to both sunglasses and spectacles.
So which lens material is best for sunglasses?
CR-39 lenses
Generally speaking, if you are looking for sunglasses that you can wear every day for different activities, CR-39 lenses are a perfect choice for you.
Although CR-39 lenses may still shatter when enough force is applied, they are much more impact resistant than glass lenses. To this day plastic lenses are still very popular and widely used by many people around the world. The number one benefit of using plastic lenses today is the fact that they are the most inexpensive lens material available.
Polycarbonate lenses
If you want to use your sunglasses mainly for sports reasons, you should avoid CR-39 and glass lenses as they are not shatter-proof and therefore not recommended for active sports. Instead, you should opt for polycarbonate lenses as they consist of remarkably strong plastic which weighs the least and is the most impact-resistant. This makes the material a perfect choice for rugged sunglasses.
Glass lenses
If clarity and scratch resistance are your priorities, think about what the word „sunglasses“ originally implied – right, lenses made out of glass. Why? To this day there have been no other materials that have been able to match glass lenses when it comes to clarity, scratch resistance, and ability to withstand extreme temperatures. However, glass lenses shatter much more dangerously than plastic lenses. Besides, they can only be mounted into full framed eyeglass frames. Therefore glass lenses limit the styles of frames that you could choose from. Last but not least, people that have sensitive noses generally do not do well with heavy glass lenses.
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