What you always wanted to know about polarised and mirrored sunglasses
Polarised sunglasses. Everyone has heard of them but no one really knows what they do or how they work. No wonder our customers keep asking questions like „are polarised lenses better for my eyes?“, and „do polarised sunglasses look different from conventional ones?“
The same applies to mirrored sunglasses. Everywhere on the streets we see fashionistas with mirrors on their eyes, but we don't know exactly whether the lenses offer other advantages in addition to their style factor.
Want to get to know the advantages of polarised and mirrored lenses? We have made the comparison.
What are the advantages of polarised sunglasses?
Polarised sunglasses look like any other pair of sunglasses from the outside.
But when you put them on, you immediately see what's different about these lenses: They have a special film that blocks reflected horizontal light rays and allows vertical light to pass through to your eyes. Vertical light brings clarity and contrast to your surroundings which results in clear vision and pure colour.
Above all, however, glare limitation is the most conspicuous feature of polarised lenses. They effectively block strong glare and surface reflections, which becomes particularly apparent when looking at a water surface.
The anti-glare properties penetrate all concentrated sunrays that are reflected from the water surface, so you can see through it. If the water is clear, you are likely to see fish and other marine life.
How do polarised lenses work?
When a polarised lens is manufactured, an essential chemical substance is applied. This substance is laminated in a vertical pattern that converts the light. The pattern, in turn, blocks the horizontal light to avoid glare.
We see glare when light waves hit reflective surfaces such as a lake, a snow-covered slope or a shiny car. The surface is horizontal, so the light is reflected horizontally. When we wear polarised sunglasses, the surface blocks glare by filtering out horizontal light waves that do not fit through the vertical chemical pattern.
Note: Polarised lenses can make the images appear darker. If glare is eliminated, though, image details will be more visible and colourful and there will be less eye strain.
How do I know if my sunglasses are polarised?
If you want to know if your sunglasses are polarised, you can find out in three easy steps.
- Turn your computer screen or phone display to its brightest setting and open a white screen.
- Put on your sunglasses.
- Tilt your head 60 degrees to the left or right. If the sunglasses are polarised, the screen will appear to turn black due to the anti-glare properties cancelling each other out.
If one side doesn’t work, try tilting your head to the other side. If that doesn’t work, the sunglasses are not polarised.
What then are the advantages of mirrored sunglasses?
Mirrored sunglasses differ from normally tinted or polarised sunglasses in their performance and appearance. And just like polarised lenses, mirrored ones offer great eye protection by preventing your eyes from straining.
The mirror-coated lenses, also called flash coatings, limit the amount of light that enters your eyes, making you feel more comfortable.
Mirrors are highly reflective coatings that are applied to the front of the lenses to reduce the amount of light entering the eye. This makes them particularly advantageous for activities in very bright conditions, such as skiing on a sunny day. Sunglasses with mirrored lenses also have a coating that makes them more resistant. On the other hand, they have a risk of colour falsification.
How do mirrored lenses work?
Mirrored glass uses both traditional tinting and a special reflective optical coating called mirror coating. This coating reduces the amount of light passing through the lenses by 10–60%.
Typically, mirrored lenses use several different coatings and are used alongside other anti-reflective coatings. A small, reflective film of metal is typically deposited first, and then other plastic coatings are used to protect it and decrease glare, providing a mirror-like finish.
And what about anti-reflective coating?
Another term that often appears in connection with mirrored sunglasses is that of „anti-reflective lenses“, which raises the question: “Aren't other lenses anti-reflective too?”
Well, on the front side of the lens they are. When wearing sunglasses, reflections are stopped mainly by the colour shade on the front of the lens. However, it is on the back of the lens where you need some help from an anti-reflective coating (AR). The AR reduces the light reflected from the back of the sunglass lens. Otherwise, the light will bounce back into your eyes and interfere with your vision.
With AR on your sunglasses lenses, you'll enjoy extra comfort and clarity by reducing blurry images.1
Ready to try your new favourite accessory?
1The experts working for the legendary lens manufacturer Zeiss explain on their website how AR coatings work.
Style advice and tips for choosing the right sunglasses