Sports + Leisure

Polarised sunglasses: comfortable vision without distracting glare

BETTER VISION explains how polarised lenses reduce irritating glare for optimum vision.

11 February 2020

Whether you’re a snow sports enthusiast, water sports junkie, or you simply enjoy spending a lot of time outdoors – polarised sunglasses can significantly reduce reflections and glare, to help you see better.

Left: without polarisation filter, right: with polarisation filter

How can polarised lenses support your vision?

Glare reflected off transparent or wet surfaces is not only annoying and distracting – it can also affect your vision. Polarised glasses may support and improve your sight in the following instances:

General light-sensitivity. Those who are sensitive to bright light will benefit from these lenses, as well as the UV protection it offers (if the lenses offer full UV protection).
If you love to fish, row, boat or do other water sports, polarised sports sunglasses will allow you to see better below the water’s surface. This may come in handy when you want to reel in that giant, or if there’s an obstacle below the water that can be potentially dangerous for your boat or canoe.
Driving. When we’re on the road, we’re often distracted by glare, caused by sunlight reflected off wet roads, windscreens and car bonnets.
Snow sports. When combined with the traditional rose or yellow ski goggle hues, polarisation filters can reduce the distracting bright sunlight reflecting off snow. However, speak to your eyecare professional before buying polarised snow goggles or using them for skiing because they can affect your contrast perception.
Post surgery. You may find that your eyes are more light sensitive for a few months after eye surgery such as cataract removal. Wearing polarised glasses can make you feel more comfortable and can help you see contrast better.

Polarised lenses drastically reduce glare from water to improve overall vision.

What does polarised mean, exactly?

Natural light travels in all directions, so it’s described as ‘unpolarised’. When rays of light are reflected by a surface such as water, snow, wet roads or windows the reflected light rays will be aligned. Basically this means that light rays that usually reflect in various directions will mainly be reflected in a single direction, so they are polarised.

The majority of this light is horizontally polarised, i.e. it is arranged horizontally.
Accordingly, the molecular structure of special film technology used in polarised lenses from ZEISS is horizontally aligned to form a dense grid. The horizontal waves are then absorbed by the highly-efficient grid structure. As a result, distracting and potentially dangerous reflections are practically eliminated by polarised lenses. In addition your colour perception will be more vibrant. High-quality lenses will also fully protect your eyes against harmful UV rays.

Unpolarised light travels in various directions, and is then vertically blocked by a polarised lens to nearly eliminate the distracting effects of glare and reflections.

ZEISS Polarising sunglass lenses

Can I wear my polarised glasses in any situation, at all times?

Although they can drastically improve your vision, there are times when they can actually impair your vision, and it’s not ideal to wear them in these instances.

Polarised sports sunglasses have some pros and cons for snow sports enthusiasts, but they’re not suited to downhill skiing. While they will reduce the glare from the sun on the snow, they may darken details in the shade. When skiers are unable to distinguish between patches of ice and obstacles, it can be potentially dangerous.

Displays on LCD screens are also often difficult to see, as the polarisation filters may reduce the visibility. Although most modern cars have improved their displays and these can be clearly seen through polarised sunglasses, those who drive older models may struggle to see important messages or warning lights. Similarly, pilots and boaters can also struggle to see LCD displays.

Always consult your eyecare professional before purchasing a polarised lens product.

To what extent can polarised glasses be customised?

With modern technology, it’s possible to apply polarisation filters to almost any type of lens. This includes prescription sunglasses for conditions such as myopia, presbyopia or astigmatism.

Polarisation also works very effectively within dynamic sun lenses such as ZEISS AdaptiveSun. These kind of special sunlenses work with photochromic technology and can adapt their intensity to changing light conditions. These lenses become very dark in intense sunlight, and turn back to moderate darkness in shade or when the sun fades.

When buying polarised sunglasses, what should I look out for?

Your lenses should definitely offer full UV protection, and you need to be aware of the fact that UV protection doesn’t come standard with all lenses. To protect your eyes from UV rays that are harmful to the eyes and surrounding skin, your lenses need to at least block rays up to 400 nm. Your eyecare professional will be able to confirm whether the brand you choose offers suitable protection. Remember to also ask about clear lenses that offer full UV protection so you’re always protected, even on cloudy days.

You can also enhance your sunglasses with an anti-reflective coating applied to the back surface of the lens, to eliminate reflections from behind.

Make the most of your sunglasses by ensuring that the tint you choose is suitable. If you’re a runner, golfer, do water or snow sports, mention this to your eyecare practitioner before choosing your polarised sports sunglasses.

Customised polarised sunglasses are often more expensive than normal sunglasses – but for good reason. The glasses will be tailored to your visual prescription and needs, and you’re assured of the protection and level of comfort.

Full UV protection in all clear ZEISS lenses

Advantages	Disadvantages
✓ Superior glare reduction, also when driving	It’s a bigger initial investment than non-polarised lenses
✓ Makes it easier to see below the surface of the water, which is ideal for water sports enthusiasts and fishermen	Can affect how you see LCD displays, which should be a consideration for drivers, pilots and skippers
✓ Works well in the sun and shade, and you will still be able to see colour contrast in shadier parts outdoors	Makes it difficult to distinguish between various shades of white, so it may influence the vision of skiers and snowboarders
✓ Suitable for all seasons – especially in countries that experience snow during the winter months	If windscreens and windows have been strengthened with grids, you may be able to see these through polarised glasses. You may experience the same through a motorcycle helmet visor, so test your glasses with the helmet for compatibility.
✓ Can reduce squinting and potential eye strain due to light-sensitivity
✓ Available in a variety of colours
✓ Your sunglasses can be customised with almost any polarised prescription lenses

Find a surface or object that produces glare. It’s easiest to work with a hand mirror. Keep the glasses in your hand, horizontally, and look through them. If you rotate the glasses to about 90 degrees, the glare from the mirror will start to disappear. If your lenses aren’t polarised, it will look the same or even appear brighter.

Another easy way to test for polarisation is to use other polarised items such as LCD screens, PC monitors or an extra pair of polarised sunglasses. Hold the glasses in front of the screen or glasses, turn them to about 90 degrees, and notice whether they turn completely dark or black. If they do, your lenses are polarised.

If you’re still unsure, ask your nearest optician to check out your glasses.
No. Polarised glasses do not lose their functionality over time, unless the lenses crack, chip or break. If you feel that your eyes are more light sensitive and you think your lenses are to blame, there may be other factors to consider. Your prescription sunglasses may be too weak or not suitable anymore, or you could have another underlying condition that causes light sensitivity. If you experience this, book a consultation with your eyecare practitioner and take your glasses along.
Polarised lenses are available in almost any colour you can think of, but speak to your eyecare practitioner about what you intend to use your tinted glasses for before choosing a shade.

Yes, they are available in a variety of colours, but you should be aware of the fact that darker colours provide higher levels of polarisation.

Remember that some coloured lenses have limitations, and you can’t necessarily wear them for every occasion. For example, certain colours may hinder you from seeing traffic lights when you’re driving.
Definitely not. In fact, because they reduce glare, they automatically reduce the eye strain you may experience outdoors in any season. You’ll find that you squint less, and see better colour contrast when wearing your polarised glasses.
Yes. They can actually improve your vision when driving by reducing the annoying glare reflected off objects on the dashboard through the windscreen, wet roads, snow, white sidewalks and metal. Just be aware of the fact that you may struggle to see the LCD displays in certain cars.
No other lenses on the market can reduce glare better than polarised ones. However, at the end of the day the purpose you want to use your sunglasses for will determine your choice. Before making your final decision, consider the disadvantages listed above, and get advice from an eyecare professional.
Although most polarised lenses also provide UV protection, keep in mind that there’s a difference between full UV protection and polarisation. Make sure that your eyes are fully protected from harmful UV rays by purchasing lenses that block up to 400 nm.