Polarized lenses were first developed in the late 1930's by Edwin Land, the founder of Polaroid. In the 70's, 80's and early 90's they were popular primarily among fisherman and boaters. Only in the last 15 years or so has the popularity expanded to be applicable in nearly every outdoor activity, even for the less active casual sunglass wearer. As it is still one of the fastest growing segments in eyewear, polarized sunglasses and safety glasses are available in many different styles and tints for both men and women. SafetyGlassesUSA.com carries nearly 150 styles of polarized safety glasses and sunglasses, including fit-over glasses for prescription wearers.
What is polarized light?
All reflected and refracted light has some degree of polarization. That is, the oscillating waves move across one (or few) plane(s) versus the infinite planes light waves would usually travel in.
The scenario most people associate the polarizing effect with is reflection off a horizontal surface, such as a lake, road, snow on the ground, or other traffic. When reflecting off a relatively smooth surface, especially one that is more or less horizontal, those light rays become horizontally polarized and, with a couple other laws of physics at work, they create the unpleasant glare.
How do polarized glasses work?
A polarized lens includes a polaroid filter, one that is vertically aligned. Much like vertical Venetian blinds would block a large portion of light, this more selectively, but effectively, blocks the glare-causing horizontal rays from passing through the lens.
Effectiveness of the lenses can vary, depending on:
- The angle of incident (the direction of the light source in relation to the surface hit with light
- The surface material causing the reflection
- The angle of your lenses in relation to the reflection or glare.
Why is this important?
Glare from reflected sunlight can be dangerous because it is an intense light that is difficult to avoid. We know not to look directly at the sun, but sometimes we must look in glare's direction. Such is the case when driving and blinding glare is dead ahead.
Warning 1: Reflections and glare are how we most easily identify ice patches on the road. With polarized glasses removing the glare or reducing the apparent reflected light from that surface, ice could be difficult to see.
Warning 2: Some instrument panels and displays may be more difficult to read with the use of polarized lenses. Drivers should take care to know which displays cannot be easily read in the vehicles they drive.