1) Polarized vs. Non-Polarized?
Non-polarized lenses treat all sunlight equally and reduce the overall intensity. This offers protection for the eyes but will not tackle shimmer and sparkle if you’re around water, snow, or glass.
Polarized sunglasses also filter ambient light but go further by canceling out bright reflected light. This advanced performance can allow:
- Anglers to see beneath the surface of a lake or river.
- Boaters to ‘read’ the texture of waves more clearly.
- Drivers to focus unhindered on the road ahead.
- Beach-goers to pick out the colors, contours, and contrasts of the sand and water better.
- Both types of lenses make for more eye comfort on a sunny day, but polarized lenses actively counter the incapacitating effects of bright sunlight.
Bear in mind that polarized lenses don’t perform as well as non-polarized when it comes to reading digital screens or displays, making them not as common among pilots. Likewise, polarized lenses make it harder to distinguish shiny patches of ice for those out walking, skiing, or driving after a snowfall, even if they do reduce overall glare.
Polarized lenses can significantly reduce eye strain, eliminate reflection, and improve performance in circumstances where the level of sunlight is overwhelming. If conditions are simply cloudy or overcast, a standard pair of non-polarized sunglasses should be sufficient to give your eyes that all-important UV protection.
2) What is UV Protection?
Think of UV protection sunglasses as sunscreen. Ultraviolet eye protection matters, especially in sunny places. Too much exposure from the sun’s UV rays has been linked to extensive eye damage. This can include cataracts, pingueculae, macular degeneration, and even sunburns on your cornea.
Not only protecting your eyes from the sun, it’s important to wear sunglasses in the shade too as UV rays reflected from buildings and other surfaces are dangerous. UV sunglasses are also a necessity in the winter as snow can reflect 80% of UV rays. Ultraviolet radiation and your eyes do not mix well together. Being prepared with protective eyewear will save you in the long run.
The American Optometric Association suggests when purchasing sunglasses, consider the following:
- 99 to 100 percent protection of UVA and UVB rays.
- Screen out 75 to 90 percent of visible light.
3) What is 400UV?
Sunglasses that are labeled UV400 blocks 99 to 100 percent of UV light. This rating ensures that all light rays with wavelengths up to 400 nanometers, including both UVA and UVB rays, are blocked out.
4) How to Tell if Lenses Are Polarized?
Polarized and non-polarized lenses look the same, which is one of the reasons why you should test sunglasses labeled ‘polarized.’ To do so, look through the lenses at a reflective surface then turn the lenses 90 degrees. If the lenses are genuinely polarized, the bright reflection will appear.
Alternatively, hold the lenses in front of a backlit LED screen and rotate. This time, the screen will become darker for polarized lenses, whereas non-polarized lenses will reveal no change.
5) How to Test UV Protection?
We'll cut straight to the point, there are only two ways to test the UV protection of sunglasses. The first is to visit your local optician to see if they can test the lenses for you. The second is to test them yourself with a UV light flashlight at home.
Home Testing Steps
1) With a UV flashlight you can shine the light beam at paper money or a credit card to reveal the built-in security elements. These security elements will illuminate and appear to glow when exposed to UV light.
2) After you have confirmed the security elements have reacted to the UV light, take your flashlight and direct the beam through the lens of your sunglasses. If the security elements are no longer visible, then your sunglasses have 100% UV protection.