Are Sunglasses Bad for Your Eyes: The Facts

Sunglasses are far more than just a fashion accessory; they’re necessary protection for your eyes. A good pair of sunglasses can prevent degradation of your eyesight, reduce your risk of eye cancer, and so much more.

In this post, we’ll take a look at a few of the most common myths about wearing sunglasses and give you concrete facts on why the right pair of sunglasses is important for good visual health.

We’ll look at a few risks that come with sunglasses (particularly the wrong glasses) and wrap up with a few simple, easy-to-follow guidelines for sunglasses use.

The Debate on Sunglasses and Eye Health

The biggest arguments as to why wearing sunglasses is not healthy include:

• They reduce your exposure to sunlight, thereby affecting your sleep-wake cycle and impairing your circadian rhythm.
• They prevent your eyes from absorbing sunlight and producing Vitamin D.
• They may interfere with your depth perception and limit peripheral vision.
• They stop your eyes from adjusting naturally to different lighting conditions, potentially making them less responsive and more sensitive to light.

While these arguments do hold some validity, there is not a lot of empirical evidence collected by clinical studies to back up the claims. Any data is anecdotal at best.

But what multiple studies can confirm is that sunglasses offer you the protection you need most: protection from UV radiation in sunlight.

How Sunglasses Shield Eyes from UV Rays

The sun lets off two forms of radiation: UVA rays and UVB rays. Both UVA and UVB rays can penetrate your skin and eyes, changing the structure of your skin and eye cells.

Too much exposure can cause damage—including sunburn and eye strain—which, over time, can accumulate into more serious problems, including skin cancer, vision loss, and accelerated age-related macular degeneration.

Many sunglasses, however, offer protection for your sensitive eye cells from these ultraviolet rays. A good pair of sunglasses will protect you from 95 to 100% of UV rays (it’ll say it right there on the label) in wavelengths up to 400 nanometers (UV400). This is the wavelength most likely to damage your eyes, so the sunglasses will protect your eye health while still allowing you to see clearly.

The Need for UV400 Protection and Lens Quality

The combination of UV400 protection and a good pair of lenses is crucial for protecting your eyesight while out in bright sun.

The UV400 protection will shield you from the damaging ultraviolet radiation in sunlight (UVA and UVB rays), while good quality lenses will ensure your vision is clear and unaltered, your depth perception intact.

Do Sunglasses Weaken Your Eyes with Overuse?

Sunglasses do not weaken your eyes if used correctly—i.e. when out and about in the sunlight.

Wearing sunglasses will not result in your eyesight weakening or vision deterioration. A good pair of sunglasses will simply protect you from the sun, both ultraviolet rays and the fatigue caused by exposure to bright sunlight, without leading to harm or weakened eyes.

The Biggest Risk of Cheap Sunglasses: Lack of UV Protection

The greatest risk to your eyes will only occur if you wear cheap sunglasses.

Cheap sunglasses tend to be made using only colored plastic, which blocks light from reaching your eyes but not UV rays. That means your eyes are fully exposed to all the radiation in sunlight, putting you at greater risk of eye strain and eye cancer.

Do Dark Lenses Dilate Pupils and Increase Sensitivity?

When your eyes are exposed to bright lights, your pupils constrict to protect the sensitive retina and regulate the amount of light that enters your eyes. In low-light conditions, your pupils dilate to allow more light to enter your eyes.

Wearing sunglasses does cause greater dilation of your eyes. The reduced glare and brightness means your pupils need to dilate to allow more light to pass through. If you are wearing cheap sunglasses that offer no UV protection, the dilation of your pupils also permits more radiation to reach your retinas and damage the cells of your eyes.

This is yet another danger of cheap sunglasses, and a reason you should always buy glasses with quality lenses that provide UV400 protection for 95 to 100% of solar radiation.

As for increased sensitivity to sunlight, there is no concrete evidence to suggest that proper use of sunglasses reduces your eyes’ ability to respond to bright light stimuli. It may take a moment for your eyes to adjust once you take off your sunglasses, but they will not become less responsive or more sensitive just because you wear sunglasses.

Effects of Overusing Sunglasses Indoors

There is a danger of using sunglasses indoors.

Inside, you are already in a lower-light environment, with very little natural light and far more artificial light (which is already a strain for your eyes). By dimming your environment further, you force your eyes to work harder to adapt to the low-light conditions to see clearly. The constant dilation of your pupils can lead to eye strain, fatigue, and blurred vision.

Only people with excessive sensitivity to light (photophobia) should wear sunglasses indoors.

Comparing Polarized, Photochromic, and Tinted Lenses

Polarized sunglasses feature a polarization coating, which reduces glare. These are particularly helpful when you’re driving, cycling, or anywhere near skyscrapers with large glass surfaces—really, anything that could reflect sunlight into your eyes.

Photochromic sunglasses are also called “transition lenses” because they automatically darken when exposed to bright light, but return to their normal transparent state when indoors. A good pair of photochromic lenses will provide UV protection and possibly even glare reduction, while still permitting you to see clearly in low-light environments.

Tinted lenses not only provide protection from bright light (and radiation, if they have a UV rating), but can also enhance color contrast in your environment.

Here are the differences between different tint colors:

• A blue or purple tint reduces glare, improves your perception of colors, and works well in snowy or foggy conditions.
• A yellow tint filters out blue light from electronic devices (which is why most blue light blocking glasses use this color tint), but may cause minor color distortions.
• A green tint transmits colors evenly, brightens shadows, dims glares, and provides good color contrast even in low-light conditions.
• A red or pink tint reduces eye strain, enhances depth perception, and improves contrast.
• A gray or black tint is great for everyday use, reduces glare, and provides the best color perception.
• An amber or brown tint is good for variable conditions and can reduce blue light exposure from electronics.

Tint color directly shapes how your eyes interpret light, contrast, and color in different environments. Each hue manipulates visual input in a distinct way, enhancing certain conditions while compromising others.

Sunglasses for Kids: Key Developmental Points

Children likely spend more time in the sun than adults, and their developing eyes are more sensitive to UV radiation. Excessive sun exposure can lead to faster degeneration of their eyes as they grow into adults and raise their risk of eye cancer.

That means children should definitely wear sunglasses, just like adults.

The right pair of sunglasses for your child should have the following properties:

• UV protection against both UVA and UVB rays;
• A sturdy frame (made from materials like polycarbonate) and scratch-proof lenses that can withstand roughhousing and active use;
• A frame shape that snugly fits on their nose and fully covers their eyes to block out sunlight.

Have a conversation with your child to help them understand the importance of wearing sunglasses when they’re out in the sun. Make sure to model good behavior, too, by wearing them yourself.

How To Wear Sunglasses Correctly

To avoid sunglasses misuse, follow these tips:

• Ensure your sunglasses are a snug but comfortable fit on your face.
• Position the lenses to fully cover your eyes.
• Make sure the frame doesn’t obstruct your field of vision.
• The upper edges of the frame should stop just below your eyebrows, while the lower edges should reach your cheeks (but not extend farther).
• Wear sunglasses suited to your activity.
• Choose a tint color that works best in your particular environment or which suits your specific preferences.
• Make sure the glasses feature proper UV protection (99-100% UVA/UVB or UV400), and add polarization as needed.

Most important of all, make sure to wear sunglasses anytime you’re out in bright sunlight to shield your eyes from exposure.

Which Eye Conditions Require Caution with Sunglasses

People with glaucoma, keratoconus, photokeratitis (also called “corneal sunburn”), and photophobia (light sensitivity) should all consult their doctor before deciding which sunglasses to wear.

Anyone recovering from surgery for cataracts, eye injury, or vision correction surgery should also be cautious with their sunglasses use.

Conclusion: Are Sunglasses Beneficial or Harmful?

A bad (read: cheap) pair of sunglasses made only from colored plastic, without UV400 protection, can be harmful for your eyes. Without UV protection, low-quality sunglasses increase your risk of eye cancer and vision loss.

A good pair of sunglasses, on the other hand, offers maximal UV protection and protects you from eye strain caused by excessive sunlight. They’re an investment that usually pays off and will benefit your eyes and extend their function for many, many years.

Frequently Asked Questions

Are prescription sunglasses a good idea?

If you wear corrective lenses or contact lenses to counteract vision impairment, it’s definitely a good idea to wear prescription sunglasses. Wearing regular sunglasses without prescription may lead to headaches, eye strain, blurry vision, and reduced visual quality.

Are more expensive sunglasses worth it?

Expensive sunglasses tend to be made using higher-quality materials, and may be sturdier as well as more stylish. However, in terms of protection for your eyes, you can find affordable options that provide the same UV shielding, polarization, and tint as much costlier glasses.

What to avoid when buying sunglasses?

Avoid buying cheap glasses with lenses that are made from colored plastic or glass, but with no UV protection. Cheap frames are also more likely to break with regular or active use. Small glasses that fail to fully cover your eyes (like the John Lennon style) may look stylish but offer less than effective protection from sunlight.

Resources

Sunglasses and Your Eyes

9 things to know about sunglasses, eye protection and cancer

Do Sunglasses Actually Protect Your Eyes?

How Sunglasses Help Protect Your Eyes’ Health

Do children need sunglasses?