Polarized lenses: how and when to choose them
Polarized lenses have a protective function against the sun’s rays and offer real benefits for eye health. If you’re looking for a new pair of sunglasses, consider those that come with polarized lenses.
What is a polarized lens?
Polarized lenses are laminated with small vertical stripes that allow only vertically angled light to filter into the wearer’s eyes. Glare is eliminated because horizontal light waves cannot pass the vertical filter.
Sunglasses and camera lenses are often polarized to reduce glare from surfaces, such as light reflected from a lake or the hood of a car. When light bounces off a surface, its waves usually propagate horizontally, vertically, or diagonally. This phenomenon is called polarization.
Polarized lenses contain millions of parallel rows of tiny iodine crystals or dichroic dyes so small that they cannot be seen with the naked eye. The horizontal rows of iodine crystals contained in the polarized lenses block polarized horizontal light waves, leaving only vertical (non-polarized) light waves to reach the eye.
Polarization blocks up to 50% of the light that passes through a lens. In most cases, the person looking through the lens continues to see clearly, but with reduced brightness and without glare. This gives you a very comfortable view.
What does glare consist of?
When light bounces off a surface, its light waves travel in all directions. Some of the light travels in horizontal waves, while others travel in vertical waves. When light hits a surface, the light waves are typically absorbed and/or reflected randomly. If light hits a reflective surface (such as water, snow, even cars or buildings) at the right angle, some of the light becomes “polarized” causing glare that can interfere with vision by hitting the eyes intensely. Only polarized lenses are able to eliminate this glare.
Why choose polarized lenses?
Polarized lenses differ from regular sunglasses in several ways. They offer advantages in terms of visual comfort, protection from UV rays, as well as being elegant and versatile.
These lenses do what no other lens or coating can do, which is block blinding glare. This type of lens improves visual acuity, color contrast, visual comfort by blocking 100% of harmful UVA and UVB rays.
We have all been dazzled, perhaps spending the day at the beach, driving in a car with the sun reflecting off the dashboard, roadway or bonnet, or on a boat with the sun illuminating the surface of the water. Usually, this glare is annoying to the eyes, but when the angle of reflection is right, the glare can become blinding and often even dangerous, as in the case of driving a vehicle.
Normal tinted sun lenses only reduce the ambient light that reaches the eye, i.e. light transmittance. By their very nature, they cannot block glare. Only polarized lenses can block this dangerous glare.
Polarized lenses: in which cases are they indicated?
When choosing sunglasses, there are many features to take into account. Not only the aesthetic appearance of the frame and the comfort of wearing them, but also the importance of effective UV protection.
Polarized lenses should be chosen:
- to reduce glare. The main feature that distinguishes polarized lenses from regular sunglasses is the ability to reduce glare caused by sunlight bouncing off flat surfaces and reflecting back into the eyes and causing discomfort. Flat surfaces can be the dashboard, other cars, the road, or bodies of water. The result is blinding glare that can impair activities such as driving.
- Have greater protection from UV rays. UV protection for the eyes is just as important as UV protection for the skin. Studies have shown that overexposure to UV rays is directly responsible for eye diseases such as cataracts. Polarized lenses offer the highest level of UV protection, superior to that offered by common sunglasses.
- To follow the trends of the moment. Polarized lenses are available in a wide range of colors and finishes, allowing you to wear the latest styles and fashion trends, while protecting your eyesight. Iconic colors (brown, gray and gray/green) offer better color perception while fashion colors such as ink blue, purple blue, sky blue and purple allow you to show off a new look, improving visual comfort.
When it is preferable not to use polarized lenses
The polarizing strips reduce the amount of light that filters down to the eye. Polarized lenses should not be used at night or in other situations where clear lenses are needed. You can’t make these lenses really clear: even those with low levels of polarization have a slightly gray hue.
Polarized lenses can cause distortion when looking at liquid crystal (LCD) screens, making some mobile screens, watches, and other displays unreadable.
