The most important function of sunglasses is their provision of 99-100% UV protection for your eyes. UV protection is mandatory whilst polarization is an optional upgrade which simply blocks glare for visual comfort and provides no extra protection.
Searching online, there's so much hype surrounding polarized sunglasses that it's a common misconception they're a better option. But this is only true if polarized lenses provide UV protection in the first place.
I could end this blog post here.
But to fully understand the difference between UV protection and polarization will help you make an informed decision towards your next set of shades.
If that sounds helpful, this is the article for you.
Onwards.
What are UV sunglasses?
UV, 100% UV and UV400 all signify that a sunglasses frame is fitted with protective lenses which (a) block ultraviolet light emitted from the sun ranging between 100 to 400 nanometres (nm) and (b) reduce visible light between 75-90%. This means they block 99-100% of UV light consisting of UVA, UVB and UVC light; the most damaging frequencies to your eyes and skin whilst providing good visual comfort.
What are CE sunglasses?
On any legitimate sunglasses frame, you should see a small CE logo stamped on the interior surface of the frame, usually on one of the temples (arms). This signifies the sunglasses conform to the European standard EN ISO 12312-1:2022 and that the lenses provide UV protection up to 380 nanometres.
- CE stands for Conformité Européenne (European Conformity).
- All legitimate sunglasses must be CE marked.
- But not all sunglasses are rated as UV400.
Why is UV protection important?
UVA and UVB rays pose significant risks to our eyes. Prolonged exposure without adequate protection can result in various eye problems, such as cataracts, macular degeneration, and cornea burns, also known as photokeratitis.
UVC, the least harmful frequency of ultraviolet light, is largely intercepted or absorbed by the earth's atmosphere. Nonetheless, a minor fraction of this light penetrates through, underscoring the importance of UV400 sun lenses that provide protection against it.
|
UV light sub-type |
Frequency (nm) |
Danger to eyes & skin |
|
UVA |
315 - 400 |
High |
|
UVB |
280 - 315 |
Medium |
|
UVC |
100 - 280 |
Low |
What are polarized sunglasses?
Polarized sunglasses use additional filters which reduce glare from surfaces such as water, snow, and glass. Glare is a phenomenon where light waves bounce off reflective surfaces at unwanted angles, causing visual discomfort and reduced visual clarity.
The filter within polarized lens is called a polarizer. This thin chemical film is applied as a layer either upon the lens' surface or sandwiched within two layers of the lens construction.
The polarizer contains microscopic rows of neatly aligned molecules which are orientated vertically in relation to you and your sunglasses. These vertical rows block horizontally reflected sunlight (glare) which is how they provide significantly smoother vision compared to non-polarized lenses.
Comparing UV and polarized sunglasses
Regular UV sunglasses are perfectly suitable for almost any application. Although the don't block glare, they provide 99-100% protection against invisible UV light.
Furthermore, UV sunglasses can be fitted with varying colours and darkness's of lenses to suit your prescription, lifestyle and intended application.
In fact, UV lenses are much more prevalent than polarized lenses as they're easier to manufacture - without the additional polarizer film upon or within the lens.
Subsequently, non-polarized lenses are on average 30% cheaper overall and will easily handle most light conditions, for most people, most of the time.
Only if you desire better glare reduction should you consider polarized lenses.
For the same reasons above, this is why polarized lenses are more costly. They're more intricate to manufacture and tend to be around 25-30% more expensive on average.
4 reasons to upgrade to polarized sunglasses
- Enhanced Clarity and Comfort: Polarized lenses reduce glare from reflective surfaces, providing clearer, more comfortable vision in bright conditions.
- Reduced Eye Strain: By blocking harsh, reflected light, polarized sunglasses can help minimize eye strain, making them ideal for prolonged use outdoors.
- Improved Visual Precision: These lenses improve the sharpness and contrast of your vision, which is particularly beneficial for activities like driving or water sports where accuracy is crucial.
- Safety: With improved visibility in bright conditions, polarized sunglasses can enhance safety during outdoor activities and driving by reducing glare-induced distractions.
Can sunglasses be both UV protective and polarized?
Yes, sunglasses can simultaneously be both UV protective and polarized. This is because UV protection is added as a coating whilst the polarizer film is either applied externally or sandwiched within two layers of each sunglasses lens. The UV coating blocks invisible ultraviolet light and the polarizer filter block visible light (glare).
Shopping around, you might've noticed that polarized sunglasses come in a wide variety of options including frame types, lens material, lens colors and types of prescription.
Depending on your lifestyle and corrective prescription, there are various factors to consider if you're looking to invest in some good quality sunglasses with polarized lenses.
How to choose the right polarized sunglasses for you
Although there's many shapes, styles and brands to choose from, there are two main sunglasses frame formats.
Polarized sports sunglasses are typically very lightweight with strong base curvatures that closely wrap around your head and eyes. These performance orientated frames are mass produced, usually injection moulded from thermoplastic material such as nylon (TR90) with little craftmanship.
Polarized fashion sunglasses are typically made from acetate and/or metals such as titanium or nickel alloy with aesthetics and fashion trends in mind. These frames feature low base curvatures, thus being much flatter and less closely fitted to your eyes. Instead of injection moulding, fashion sunglasses are manufactured using multiple automated and manual processes during manufacture.
For lightweight performance, wraparound polarized sports sunglasses are an obvious choice. If fashion and aesthetics are more important to you, polarized lenses can fitted to just abut any frame you like the look of.
Lens material
Not all polarized lenses are made equal. They can vary vastly in terms of material, quality and optical performance which can read about in this article. But as a quick reference, here are the four main types;
- Acrylic: a budget polarized lens option with moderate durability and scratch resistance
- Polycarbonate: Lightweight and impact-resistant, ideal for sports and active lifestyles.
- CR-39: Offers clear optics and is lighter than glass, fantastic for prescription use.
- Glass: Provides superior clarity and scratch resistance, but prone to shattering
Summary
In short bullet points, summarise this blog post.
- UV protection is mandatory, whilst polarization is optional
- UV protection blocks invisible ultraviolet light (UVA, UVB & UVC).
- Polarized filters visible light (glare).
- UV400 blocks ultraviolet light ranging between 100-400nm.
- Check for the CE marking on sunglasses to ensure they're legitimate.
- Sunglasses can be both UV and polarized
Hopefully you found this article helpful. If so, please check out our other polarised sunglasses blog posts for more helpful advice.
Thanks for stopping by.