There is a lot of misinformation out there when it comes to sunglasses and how they can protect your eyes. Polarized sunglasses in particular are said to have better protection than regular sunglasses, blocking glare and helping in certain lighting situations that other sunglasses cannot offer. While this is true, it is important to understand the truth behind these claims. Here are some myths (and truths) about polarized sunglasses.
Polarized sunglasses fully block glare
This is a very generalized statement, and the relationship between light, glare, and polarization is complicated. Normal light moves on many different planes, but polarized light comes from light waves that have been reflected off of a surface and moves mostly along one plane. What a polarized filter does is effectively blocks light that is polarized at a 90-degree angle from the lens. More light is reflected and polarized horizontally, so polarized sunglasses are polarized vertically to handle the glare coming off of horizontal planes. Because of this relationship between polarization and glare coming from specific angles, polarized sunglasses will not always effectively block all glare at all times.
Polarized sunglasses are expensive, so they must work
Price is no guarantee of quality when it comes to sunglasses. The reality is expensive polarized sunglasses may not even meet industry standards for UV protection, and many inexpensive sunglasses meet or exceed those same standards. The easiest way to know you are getting what you paid for is to check them yourself- be sure to read the UV protection label on the sunglasses you are about to purchase to see if they meet industry standards. Many polarized glasses have a test tag you can use to truly determine if they are polarized by looking at the tag through the lenses and moving it around to different angles. If they are of good quality, you should notice a significant darkening effect at certain angles as you move them around. If you are looking for UV-A and UV-B protection, polarized sunglasses may not have you covered. Polarized does not mean they protect against UV rays- a separate material must be added to the lenses to absorb the harmful radiation.
Polarized glasses make it hard to see LCD display
This is true. At certain angles, polarized lenses actually make LCD displays completely disappear. This is due to the nature of the liquid crystals producing the display, and how the polarized lenses filter this type of light. A lot of ATM machines, car and motorcycle displays, and even home appliances use LCD. Because of this, be sure to avoid polarized lenses when operating any vehicles that have LCD controls!