Polarised lenses are an innovative solution to reducing glare and protecting your eyes while outdoors. Using a chemical coating these lenses are able to block reflected light from flat surfaces. This reflected light is often unexpected and can cause eye strain and temporarily reduce vision, meaning that polarised lenses can provide greater protection and comfort while outdoors.
The Science Behind Polarised Lenses
Polarised lenses work by filtering out a certain kind of light that is responsible for glare.
When light hits a flat surface (like snow, water or glass) some of the light is reflected and some is absorbed. The reflected light (called polarised light) is travelling on a single plane — the light waves are only moving horizontally.
Because this light is concentrated in one direction we perceive it as glare. This is the brilliant light we see when the sun catches water or a glass pane.
Polarised lenses work by filtering out the polarised light that causes glare. A minute grid or filter is used, which only allows light that is travelling on a certain plane. In this way, a polarised lens can filter out glare caused by light reflecting off a horizontal surface.
This is why when you wear polarised lenses, you can see more clearly into a body of water on a sunny day, minimise glare from roads and avoid being dazzled when skiing on snowy slopes.
How Polarised Sunglasses Work
This technology is applied to tinted lenses to create polarised sunglasses. The term is familiar to most people, but how do these lenses reduce glare and protect our eyes?
As we’ve discussed, polarised lenses work by filtering out horizontal light waves that are responsible for glare. Normal sunglasses provide tinted or darkened vision, but with polarised sunglasses, glare reflected from flat surfaces is removed or reduced. This provides the wearer with clearer more comfortable vision.
Your eyes may react to glare by squinting or tensing and you may not be able to look in certain directions without discomfort — with polarised sunglasses, you can see clearly throughout your field of vision without straining your eyes. If you spend a lot of time outdoors, protecting your eyes from glare can have positive effects on your eye health.
Advantages of Wearing Polarised Sunglasses
All sunglasses offer a variety of benefits, but the polarised options have a specific set of advantages that include improved vision, less eye strain, increased comfort and even improved safety while carrying out certain tasks.
On a sunny day, all sorts of flat surfaces can reflect light making it difficult to see, which can lead to eye strain and reduce our ability to drive and play sports effectively. Glare can appear suddenly, temporarily reducing your vision; in some instances, this may only be frustrating, but in others, it could be dangerous. In this way, polarised sunglasses can improve your safety as well as your comfort while carrying out tasks like driving.
One reaction we have to glare is squinting. Squinting involves tensing the muscles around the eyes to try and focus better. When these muscles get fatigued some people experience eye strain and headaches. Anyone who has experienced eye strain knows that it can be very uncomfortable and make it difficult to carry out simple tasks. By eliminating or reducing glare, polarised sunglasses can stop us from squinting so much and reduce eye strain and headaches.
One of the main appeals of polarised sunglasses is that for many people they offer a clear and comfortable field of vision with less sharp contrasts. Aside from the benefits for eye health and safety, these specialised sunglasses are popular because they enhance visual clarity and make a noticeable difference in how you see the world.
Debunking Polarised Lens Myths
While almost everyone has heard of polarised sunglasses, many don’t know how they work. This has led to some common misconceptions about them:
Polarised Lenses are the same as UV-protected lenses.
UV-protected lenses block harmful light given off by the sun, while polarised lenses reduce glare. While both are good for your eyes, they provide completely different benefits. That said, many sunglasses are both polarised and treated with a UV-protection coating.
Polarised lenses get rid of all glare.
While polarised lenses are extremely effective at reducing glare reflected off flat surfaces, they cannot block all kinds of glare. This is because polarisation involves filtering out light waves on a horizontal plane, meaning reflected light from other angles can still get through the lenses.
Polarised lenses make it impossible to see LCD screens.
This is partially true. LCD screens (for example, smartphone screens) are often polarised in a slightly different way to spectacle lenses or sunglasses. This can lead to them filtering out light coming from different planes, making the screen look black. However, some devices are now being designed to counteract this effect. Also, rotating the device can make it possible to see these screens while wearing polarised lenses.
Tips for Choosing the Right Polarised Sunglasses
When picking out your next pair of sunglasses, you may be thinking about your favourite style or the latest trend, but finding the polarised pair which is best for you should also be on your mind. Here are some tips for picking polarised sunglasses that are right for you.
- Make sure your sunglasses really are polarised. If you’re buying from an optical practice this shouldn’t be a problem. The dispensing optician will let you know and polarised lenses are clearly advertised. If you’re buying your sunglasses elsewhere it’s a good idea to test them out to make sure they are blocking out glare from a reflective surface.
- Look for UV protection as well. Many sunglasses offer either polarised lenses or UV protection, but there are plenty that offer both. Protecting your eyes from UV light can minimise your risk of developing vision loss and eye conditions like cataracts and macular degeneration.
- Find the right tint for you. Part of what makes polarised lenses great is the clear and comfortable vision they provide. This is most effective when you find a tint or colouring that works best for you. Common colours include grey, brown, yellow, green and mirrored. Aside from your preference, these have different benefits in terms of clarity, contrast and glare.
- Prescription options. Polarised sunglasses are available with your precise prescription. Going for the prescription option is important to guarantee you get clear vision in every environment.
Caring for Your Polarised Lenses
As with any eyewear, caring for polarised sunglasses or spectacles allows you to enjoy optimal vision and comfort for longer.
It’s important to note that you should always follow your manufacturer's guide for the care and maintenance of your polarised eyewear, as lenses differ in material and coating.
That said, here are some tips for looking after your polarised lenses:
- Cleaning should be carried out using warm water and a microfibre cloth. The water is there to remove any excess dirt or dust, before using the cloth to remove smudges and marks. Never use tissue paper or other materials to clean your lenses as they may damage the surface or the coating of the lens.
- Protect your lenses from scratches and damage. This may seem obvious, but many of us are in the habit of keeping eyewear in our pockets or handbags without a case. It’s very easy for lenses to be scratched in these conditions and with polarised eyewear this can damage the coating.
- Avoid leaving your eyewear in extremely hot environments. This most commonly occurs when you leave your sunglasses in a hot car. Extreme heat can warp the frames of your eyewear and affect the coating leaving you with distorted vision and uncomfortable wear.
Polarised Lenses vs. Non-Polarised: A Comparison
If you’re debating whether polarised lenses are worth it, here are some comparisons to help you make your decision:
- Glare reduction. The main purpose of polarised lenses is to reduce glare, while regular lenses simply provide corrected vision and sunglasses tint your vision to make it more comfortable.
- Cost. Because of their added benefits polarised lenses tend to cost more than regular ones. Price will vary widely depending on your choice of frames and lenses, but the polarised option will often be an additional 20 - 40% of the cost of your eyewear.
- Clarity of vision. Many find that polarised lenses provide clearer vision when outdoors. The reduction of glare limits squinting and allows us to experience a complete field of vision more comfortably and clearly. While conventional sunglasses may offer a similar effect, polarised lenses tend to be more effective.
- Activities. In sports like skiing, hiking, fishing, water sports and driving polarised lenses provide huge benefits and are sometimes considered an essential part of the kit. For example, polarised lenses can reduce the risk of snow blindness and are often used by mountaineers and skiers. In general, many outdoor activities are safer and more enjoyable while using polarised lenses.
- Screen Use. One of the downsides of polarised lenses is the effect they have on LCD screens. Using your smartphone can be more difficult while wearing polarised lenses and this isn’t the case with non-polarised options.
Exploring Different Lens Types: Polarised vs. Photochromic
It is worth mentioning another type of lens commonly used for sunglasses. Photochromic lenses, also known as transition lenses, change their tint based on the amount of light that hits them. In most cases, they also provide UV protection. These lenses allow people to buy one pair of glasses for indoors and outdoors and to transition between environments without having to change frames.
Photochromic lenses are convenient and cost-saving. They are also adaptive to different environments (in overcast weather, they provide a milder tint). This makes them popular with runners and cyclists, who pass through different environments and weather conditions.
Photochromic sunglasses are not usually polarised, so they do not protect from glare. In choosing between the two types of lenses, you should consider the type of outdoor activities you usually participate in and whether glare reduction or adaptability is more important to you. Both lens types offer amazing advantages – the trick is figuring out which ones most appeal to you.
