What Are Polarized Sunglasses, And Do You Need Them? Experts Weigh In

If you're in need of a new pair of shades, you’ll be faced with making the decision between choosing polarized or non-polarized lenses. But, what does it mean when sunglasses are polarized?

Below, ophthalmologist Ashley Brissette, M.D., M.Sc., F.R.C.S.C., and Andrea Thau, O.D., F.A.A.O., and former president of the American Optometric Association (AOA), answer questions about polarized sunglasses.

Brissette explained that polarized sunglasses have lenses with a special coating that reduces glare, which helps improve visibility when you're outdoors in the sun.

"The polarization helps to block certain directions of light from entering through the lens and eye," she said. "Take, for example, light bouncing off the water. When it hits the water, the light scatters into different directions, which can blur the image.”

Polarization, she added, filters out some of those rays of lights, which can “help make the image more clear and cut down on glare." However, because some of the light is filtered out, Brissette added that you'll notice things appear darker when wearing polarized sunglasses.

Conversely, if you've wondered what non-polarized sunglasses are, they're essentially just standard sunglasses that don't have the lens coating. Thau said this type of sunglasses may make it more challenging to see in certain viewing conditions, such as when it’s really bright outside, compared to polarized sunglasses.

Another essential thing to note about sunglasses is that polarization is not the same thing as ultraviolet, or UV, protection.

"UV radiation [from the sun] can cause cataracts, macular degeneration, and skin cancers around the eyes," Thau said. Sunglasses with UV protection can help to block harmful UV rays that damage the eyes and eyelid skin, Brissette said.

So, polarized sunglasses don't automatically guarantee UV protection, Thau said. She said to look for sunglasses that clearly state that they have 100 percent UV protection, which are available in various price ranges.

The short answer: It depends on what you’re doing. When engaging in outdoor activities such as boating, fishing, golfing, or spending time in the snow, polarized sunglasses can come in handy to create a clearer and more comfortable viewing experience than non-polarized ones.

"These [activities] all have the potential for light rays to bounce off of shiny objects and cause glare," Brissette said.

However, polarized sunnies don’t just have to be saved for outdoor adventures — can be useful for everyday tasks as well. Thau explained that polarized sunglasses are also great for driving a car during the daytime, as the glare from the sun reflects off other vehicles’ hoods or light-colored pavements.

When the glare is reduced, she said you can see clearly and your eyes will feel a bit more comfortable than if you had the non-polarized version. In other words, they're great for people who deal with eye strain and irritation from bright sunlight.

Thau said that people with light-colored eyes may experience more light sensitivity in bright environments such as sunlight, fluorescent light, and incandescent light than those with darker-colored eyes. That’s because darker-colored eyes contain more pigment that protects against harsh lighting.

Furthermore, it’s possible polarization could benefit most drivers. In fact, the findings of one 2009 study suggested that polarized sunglasses helped cut down drivers’ reaction time during peak daylight by up to 15 percent, compared to those who wore tinted sunglasses.

When shopping for polarized sunglasses, look for a label that indicates they are polarized, Thau said. To test them out, Brissette suggested putting them on and looking at a screen.

"Tilt your head left and right, and [if] you notice a difference in the brightness of the screen, then they are polarized," she said.

Regardless of whether you opt for polarized or non-polarized sunglasses, per the AOA recommendations, the most important thing is that you wear sunglasses when outdoors all year, even on cloudy or overcast days because UV radiation can penetrate clouds. So while polarized sunglasses may not be needed on cloudy days, sunglasses with UV protection should be worn year-round for protection. Just keep in mind that darker lenses on polarized sunglasses don't allow as much light into the eye, and Brissette said it may be tricky to see in low light settings or on cloudy days.

And for optimal protection, both Thau and Brissette said they advise purchasing high-quality sunglasses that offer 100 percent UV blocking. Be sure to verify that the label says the sunglasses have UV protection because not all polarized sunglasses have it.

Lastly, if you’re unsure what the right type of sunglasses are for different activities and your eyes specifically, consult with an expert, Thau said. In this case, seeing an optometrist or ophthalmologist is highly recommended, as they can provide yearly comprehensive eye exams and make recommendations based on your needs.

Words by Jessica Estrada