What Are Polarized Sunglasses?

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Polarized sunglasses are eyewear made with special lenses that reduce reflected glare from surfaces such as water, snow, and glass. Polarized sunglasses can be especially useful in situations where you need to see clearly and avoid hazards.

Despite what some people think, polarized lenses do not protect against ultraviolet (UV) light from the sun. Both prescription and non-prescription lenses can be polarized.

This article explains how polarized lenses work. It also lists some of the benefits and drawbacks of this type of protective eyewear.

What Do Polarized Sunglasses Do?

Polarized sunglasses are designed specifically to reduce glare so that you can see clearly in situations where you might otherwise squint or be blinded by reflected light.

Glare is caused when light hits a reflective horizontal surface, causing light beams to be scattered horizontally. This can overwhelm photoreceptors in the eyes, including rods that allow you to see in darker conditions and cones that allow you to see color.

Glare can dramatically impair your vision, making colors harder to distinguish and even "whiting out" your vision entirely. Squinting is your body's natural response to this, designed to prevent damage to the rods and cones from excessive light exposure.

Polarized lenses counteract glare by applying a special chemical to the lenses in a vertical pattern. The vertical orientation of the chemical application is what blocks the horizontal light.

This chemical process can be applied to the surface of the lenses only (for less costly sunglasses) or sandwiched between two layers of lens materials (for costlier sunglass brands).

A high-quality pair of sunglasses will almost invariably have polarized lenses.

What Are the Benefits of Polarized Sunglasses?

Polarized lenses do not block UV light from the sun which can damage the eyes. They are simply designed to prevent glare, not only during the day but possibly at night as well.

The polarization of lenses is beneficial in that it:

  • Increases your visual comfort
  • Sharpens the contrast between light and dark
  • Allow you to see true colors
  • Helps prevent eye strain and fatigue

Polarized lenses are available in a variety of colors, ranging from very dark hues to very light hues.

The color or darkness of the lens doesn't mean the lenses are "better" or "worse" at blocking glare. Both can be equally effective.

With that said, some colors are more useful in certain situations. For example:

  • A traditional dark lens can be ideal for a bright day on the lake.
  • A pale blue lens can reduce eye strain for people who work long hours in front of a computer.
  • Yellow or pale orange lenses are sometimes found in eyewear designed specifically for nighttime driving.

Because of the chemical process involved in making polarized lense, there are no true clear polarized lenses. There is always some degree of tinting, even if the shade is light.

Advantages of polarized sunglasses
Verywell / Brianna Gilmartin

When Should You Wear Polarized Sunglasses?

Glare can be dangerous, especially when driving because it distorts the true color of objects and makes objects harder to see. Glare has been linked to many pedestrian deaths and traffic accidents.

Polarized sunglasses can be especially helpful in situations like:

  • Driving: This is especially true on extremely hot days when the combination of hot air near the surface of a road and less hot air above it causes a mirroring effect.
  • Playing outdoor sports: Polarized sunglasses help athletes see with greater clarity so that they can safely maneuver while competing in full daylight.
  • Water activities: This includes speedboating, sailing, fishing, and other water sports when glare can come from all directions as sunlight bounces off waves or moving water.

How to Tell if Lenses Are Polarized

To check if your lenses are polarized:

  1. Take your sunglasses to an optical store. Grab a pair of polarized sunglasses from the shelf.
  2. Place the lens of your sunglasses at a 90-degree angle to the lens of the drugstore sunglasses.
  3. If the combined lenses turn dark or nearly black, your sunglasses are polarized.

Disadvantages of Polarized Sunglasses

Polarized lenses aren't right for everyone. There are three specific situations in which they may be more problematic than useful:

  • Visual disorientation: Some people feel dizzy or disoriented when they look through polarized lenses, particularly at normal light levels. Others say that the lenses make everything looks "more 3-D," potentially interfering with depth perception.
  • Interface blurring: The blocking of horizontal light can also make liquid crystal displays (LCDs) and other digital interfaces look a little fuzzy. This is because these technologies have directional light-modulating properties.
  • Nighttime driving: Although there are polarized lenses designed for nighttime driving, they have a dimming effect as they prevent some light from entering the eye. This can impair vision even more than even the glare from oncoming traffic.
Polarized Sunglasses
  • Reduce glare from reflected surfaces

  • Darkness or lightness of the lens does not affect how well they work

  • Can make digital interfaces look fuzzy and difficult to read

  • Improve color perception

  • Can cause the dimming of headlights at night

  • Usually made with UV-protective lens material

  • Tend to be costlier

Non-Polarized Sunglasses
  • Reflect all light but do not reduce glare

  • Darker lenses work better than lighter lenses

  • Do not make digital interfaces fuzzy but can make them too dark to read

  • Obscure color perception

  • Cannot be used for nighttime driving

  • May or may not be made with UV-protective lens material

  • Tend to be cheaper

Summary

Polarized sunglasses are designed to reduce glare caused by light this is reflected off horizontal surfaces. The chemical processes used to make the lenses are vertically oriented.

Polarized lenses are helpful for reducing glare and increasing color perception when you are driving, boating, or playing sports.

Polarized lenses aren't right for every situation. If you're driving at night or using LCD devices, the lenses cause dimming and blurring.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. American Academy of Ophthalmology. Retina.

  3. National Eye Institute. Refractive errors.

  4. American Academy of Ophthalmology. What are polarized lenses for?

  5. Boadi-Kusi SB. Austin E, Abu SL, Holdbrook S, Morny EKA. Disability glare and nighttime driving performance among commercial drivers in Ghana. J Occup Health. 2021 Jan-Dec;63(1):e12279. doi:10.1002/1348-9585.12279

  6. Ma HP, Chen PL, Chen SK, Chen LH, Linkov V, Pai CW. Population-based case-control study of the effect of sun glare on pedestrian fatalities in Taiwan. BMJ Open. 2019;9(8):e028350. doi:10.1136/bmjopen-2018-028350

  7. Federal Aviation Administration. Sunglasses for pilots: beyond the image.

By Troy Bedinghaus, OD
Troy L. Bedinghaus, OD, board-certified optometric physician, owns Lakewood Family Eye Care in Florida. He is an active member of the American Optometric Association.