What You May Not Know About Polarized Glasses
Preventing glare and protecting eyes
Edited By:Raja Sivamani , MD, MS, AP
Polarized lenses first became popular among boaters and fishermen to reduce the amount of glare from the reflected water around them. In recent years, the benefits of polarized glasses have been discovered by those who enjoy spending time outdoors, athletes, and even the everyday driver. Read on to find out how polarized lenses can benefit you.
What Do Polarized Lenses Do?
These lenses are coated with a special chemical film that helps reduce glare. Sunlight reflecting off smooth water, snow, or flat roads can create glare that is not only irritating but can often be dangerous to your eyes. Blinding sun glare can cause accidents, snow blindness, and can even sunburn your eyes. Long-term exposure to sun glare has been known to cause eye diseases. Luckily, polarized lenses can protect you from those dangers.
How Polarization Works
Light usually scatters in all directions; however, when it hits a flat surface, the reflected light shines back at your eye and is magnified, causing glare. In general, light waves from the sun or any other light source can be thought of as vibrating in both the vertical and horizontal plane, referred to as unpolarized light. It is possible to transform unpolarized light into polarized light, in which the vibrations occur in a single plane. The chemical filter that coats polarized sunglasses is designed to absorb horizontal light waves while still allowing vertical waves to pass through. Since light only travels in one plane through the polarized lenses, glare is eliminated.
Benefits of Polarized Sunglasses
In addition to reduced glare, polarized lenses also make images appear sharper and clearer which is beneficial because this increases visual clarity and comfort. Available for prescription and non-prescription sunglasses, polarized lenses can be worn indoors by light-sensitive people who are continually exposed to bright sunlight through windows.
What about “Regular” Sunglasses?
The purpose of sunglasses is to block out harmful UV rays. When we think about damage from the sun’s rays, we focus mostly on our skin; however, the sun is a serious threat to our eyes and the delicate skin around them. Sunglasses with UV protection act as sunblock for our eyes.
Just because a pair of shades is tinted darkly does not mean that they will effectively protect your eyes. Look for a pair of sunglasses specifically designed for UV eye protection that are rated UV400 or higher. This means it will block 99.9% of UV rays. Be sure to watch out for UV labels – not all sunglasses are created equal.
On a cautionary note, wearing sunglasses that are not appropriately protected may actually cause more harm than if you didn’t wear them at all. The tinted lenses cause your pupils to dilate bigger, letting in more harmful UV rays into your eye.
How to Tell if Your Glasses are Polarized
To do this quick test, you’ll need your pair of glasses and an LCD screen such as a cell phone or laptop computer. Hold the glasses in your hand out in front of you and look through the lenses from afar. Slowly rotate the lenses in either direction and watch for darkening and color changes. If the lenses do appear to be changing color, they are polarized. If nothing changes, then they are not polarized.
For the best comfort and performance with any polarized sunglasses, ask your eye care professional about having an anti-reflective coating applied to the backside of the lenses. This will eliminate distracting reflections caused by when the sun is behind you. These rays can potentially reflect off the back surface of the lenses and into your eyes.
Whether you spend your time fishing, boating, skiing, hiking, driving, or jogging, polarized sunglasses may be the right choice to help you enjoy your life outdoors.
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