What are polarized lenses?
Polarized lenses are sunglasses lenses with the addition of a polarized filter. This filter is used to improve vision by blocking glare. The polarized filter is aligned in the lenses to only allow vertically oriented light to pass through. In turn this blocks horizontally oriented light waves, commonly referred to as glare. By doing this the polarized lenses allow the wearer to see more clearly without the annoying or even blinding distraction of glare impeding vision.
What is glare?
So what is glare and what causes it? Light is typically comprised of waves moving in different directions. When light is reflected off of a flat surface whether it be the road, water or car windshield the reflected light waves concentrate creating a much brighter more dangerous form of light called glare. Glare can be very distracting and uncomfortable. This is particularly dangerous when driving as the average person can take up to 6-7 seconds to adjust to glare. Think about the dangers of driving blind for 6-7 seconds in a neighborhood with children playing.
Are all polarized lenses the same?
Not all sunglasses are created equal, there is definitely merit in the saying you get what you pay for. It is very important to make an informed purchase and make sure you are buying sunglasses with good UV protection. If you buy sunglasses with poor UV protection you can cause more harm than good. When you wear sunglasses your eyes dilate to let more light in, which could cause more harmful UV rays to enter your eye. The same goes for polarized lenses, not all polarized lenses block the same amount of glare. There are different methods of creating polarized lenses. The most common methods are the sandwiching of a polarized filter in-between two lenses or by casting a filter inside of a lens, creating a seamless solid design. Cheap polarized lenses sometimes have the filter on the outside surface of the lenses which over time can cause the lens to de-laminate and ruin the lens.
How do polarized lenses differ from non-polarized lenses?
In a non-polarized lens the lens is tinted to allow less light to pass through the lens and enter the eye. This will give the eye relief from the bright sun shine as well as block harmful UV rays from entering the eye. However these lenses don't do much for helping reduce or eliminate glare. A polarized lens is going to block glare creating better vision and better contrast.
When are polarized lenses recommended?
Polarized lenses can be beneficial for many everyday activities and sports. Polarized lenses for driving will help give the best possible vision by eliminating glare produced by the roadway and passing cars. Have you ever experienced the blinding glare of water on the roadway after a rain storm? This brings us to one of the times wearing polarized lenses will have the biggest benefit, water sports or any water based activities . Wearing a polarized lens fishing can allow you to see through the water and see the fish swimming under the surface. Other activities that polarized lenses work well include casual bike rides, golfing, hiking or simply enjoying the outdoors.
When are polarized lenses not recommended?
Polarized lenses however are not always the answer. Pilots for instance should not wear polarized lenses due to the fact that most cockpits utilize digital displays which have a polarized filter in the instrument and sometimes the windshield is even polarized. This is a problem because when you cross two polarized filters it blacks out the image making it difficult or even impossible to see. Another example of when a polarized lens is not a good option, is down hill skiing. The reason for this is that snow and ice produce different types of glare, so a polarized lens would remove the glare causing a potential accident. Road cycling poses similar dangers to down hill skiing but the danger is in the form of oil slicks which can cause slippery and potentially dangerous conditions.
Polarized sunglasses can make your outdoors experience much more enjoyable by blocking annoying glare and protecting your eyes. As we have seen, polarized lenses can be the best option for most circumstances, but for the few instances where polarized aren't the answer make sure to use a sunglasses with good UV protection. Even when cloudy, UV rays can be harmful. Protecting your eyes from UV rays should always be a priority.