Evidence Based

Polarized vs Non Polarized Sunglasses

What Are Polarized Sunglasses & How Do They Work?

Polarized sunglasses help to protect your eyes from the light that reflects off usually smooth, highly reflective surfaces like water, sheet metal, snow, and asphalt. Usually, light scatters when it bounces off an object’s uneven surface. But if the surface of an object is smooth, the light will vibrate in one direction into your eyes. That strong glare can be painful and even harmful to your eyes. Polarized sunglasses, however, reduce the reflection to protect your eyes.

polarized sunglass

The polarized lens is actually the brainchild of NASA Jet Propulsion Laboratory scientists who’d studied eagles’ razor-sharp vision. They discovered a naturally occurring oil in eagles’ eyes that control certain light properties and limit specific wavelengths. Scientists were able to mimic that effect in polarized sunglasses with a chemical that basically filters the light that meets your eye. Because the filter on polarized sunglasses is vertical (and glares are typically horizontal light), only some light can make it through each lens.

While polarized sunglasses can protect your eyes, however, understanding the difference between polarized and non-polarized sunglasses is important to your eye health. Here’s what you should know about polarized sunglasses before purchasing your first pair:

Polarized vs. Non-Polarized Sunglasses

Polarized sunglasses and non-polarized sunglasses both protect your eyes from harmful light, but they differ in a few key ways:

  • Polarized sunglasses have a specific chemical that reflects light (minimizes glare) that non-polarized sunglasses do not.
  • Polarized sunglasses absorb horizontal light waves but allow vertical waves to travel through, while non-polarized sunglasses only block the sun’s ultraviolet (UV) rays but do not prevent glares.
  • Polarized sunglasses don’t usually protect against UV light unless otherwise labeled. However, most polarized sunglasses include UV protection coatings.
  • Polarized sunglasses are typically darker than non-polarized sunglasses.
  • Polarized sunglasses tend to be a bit more expensive than non-polarized sunglasses.

Why Buy Polarized Sunglasses Over Non-Polarized Sunglasses?

You should purchase a pair of polarized sunglasses over non-polarized sunglasses if you spend a lot of time on the road or by the water. This is because non-polarized sunglasses will help to deflect bright glares from surfaces like asphalt and calm water. 

Non-polarized sunglasses have other advantages over non-polarized sunglasses, too:

  • While polarized eyewear don’t necessarily provide UV protection (unless labeled as such), they do help to reduce glares that can hurt and damage your eyes.
  • You may feel less tired as a result of less eye strain with polarized sunglasses than you would with non-polarized sunglasses.
  • Polarized sunglasses tend to show crisper, clearer images than non-polarized sunglasses.

When to Wear Polarized Sunglasses:

Polarized sunglasses help to reduce glare from highly reflective surfaces. So, you should wear polarized glasses when you are: 

  • Driving in daylight
  • Biking
  • Jogging
  • Fishing
  • Boating
  • Other outdoor activities

When to Wear Non-Polarized Sunglasses:

Non-polarized sunglasses are still a great option to keep your eyes safe from the sun’s dangerous UV rays if your non-polarized sunglasses don’t shield against UV or UVA light. You may also choose to wear non-polarized sunglasses instead of polarized sunglasses if you have trouble reading text on LCD (liquid crystal display) screens (e.g., your phone, your car dashboard, your watch, ATMs machines, etc.). 

Because polarized sunglasses can be dark, situations where you should wear non-polarized sunglasses include: 

  • Operating heavy machinery
  • Driving in low-light situations
  • Reading
  • Skiing (Polarized sunglasses may make icy patches less noticeable, which can be dangerous!)


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Author: AnnaMarie Houlis | UPDATED August 6, 2020
Medical reviewer: MELODY HUANG, O.D. | REVIEWED ON August 1, 2020
Resources

“Polarized Lenses and How They Work.” Dr. Floyd Smith | Optometrist, Westwood, NJ 07675, 31 July 2013, drfloydsmith.com/polarized-lenses-and-how-they-work-3/.

“Polarized Lenses: Are The Better for Your Eyes?: Vision Source.” VisionSource, 3 Aug. 2016, visionsource.com/blog/polarized-lenses/.

“Polarized Sunglasses.” Exploratorium, 17 June 2020, www.exploratorium.edu/snacks/polarized-sunglasses.

“Recommended Types of Sunglasses.” American Academy of Ophthalmology, 28 Feb. 2018, www.aao.org/eye-health/glasses-contacts/sunglasses-recommended-types.

“What Are Polarized Lenses For?” American Academy of Ophthalmology, 14 Jan. 2019, www.aao.org/eye-health/glasses-contacts/polarized-lenses.

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