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Sunglasses: Frequently Asked Questions

If the sun doesn't bother my eyes, do I still need to wear sunglasses?

Yes. The sun has damaging UV rays that can cause photokeratitis ,pingueculae and 

permanent retinal damage.

What exactly are UV rays?

Ultraviolet (UV) rays are located just past the violet portion of the visible light 

spectrum; sunlight is the main source.

UV light is broken into three different types: UVA, UVB and UVC.

*UVA has longer wavelengths and passes through glass easily; experts disagree 

about whether or not UVA damages the eyes.

*UVB rays are the most dangerous, making sunglasses and sunscreen a must; 

they don't go through glass.

*UVC rays do not reach the Earth because its atmosphere blocks them.

When do UV rays affect  my eyes? Most people think that  they're at risk only when  they're outside on a  sunny day, but UV light  can go right through  clouds, so it doesn't  matter if the sky is  overcast. The sun's rays  are strongest between  10 am and 2 pm.   Glare and reflections  can give you trouble,  so have your sunglasses  ready if you'll be around  snow, water or sand, or  if you'll be driving  (windshields are a big  glare source). The  following put you at  additional risk: sunlamps,  tanning beds and parlors,  photosensitizing drugs and  living at high altitudes or  near the equator.  To find out how high  the UV light levels are  today where you live,  here's a UV index map  for the United States,  updated twice a day by  AccuWeather.

Can certain medical problems increase my risk for damage from UV rays?

Yes. People with cataracts (or who have had cataract surgery), macular degeneration 

and retinal dystrophies should be extra careful. Read more about these conditions in 

our Eye Problems and Diseases section.

What are my options to prevent UV damage to my eyes?

You must wear sunglasses to prevent damage to your eyes. 

While some contact lenses provide UV protection, they don't cover your whole eye, 

so you still need sunglasses.  Look for sunglasses that protect you from 99 to 100 

percent of both UVA and UVB light. This includes those labeled as "UV 400," which 

blocks all light rays with wavelengths up to 400nanometers . 

(This covers all of UVA and UVB rays.)

Also, you may want to consider wraparound sunglasses to prevent harmful UV rays 

from entering around the frame.

What are the different kinds of lenses that are available?

With so many lenses available, it's a good idea to ask a professionaloptician for 

help when choosing sunglasses. Different tints can help you see better in certain 

conditions, and a knowledgeable optician can help you choose sunglass tints that 

are best suited for your needs.  

Blue-blockers block blue light and usually have amber lenses. Some evidence 

indicates blue light is harmful, and could increase risk of eye damage from 

diseases such as macular degeneration. These lenses are popular among 

skiers, hunters, boaters and pilots who use them to heighten contrast.  

Both polarized lenses and anti-reflective coating cut reflected glare. 

Polarized lenses in particular are popular with those who play water and snow 

sports. Anti-reflecting coatings reduce glare caused by light reflecting off the 

back surface of your sunglass lenses.

Mirror-coated lenses limit the amount of light entering your eyes, so you're more 

comfortable.  Mirror coatings (also called flash coatings) are highly reflective 

coatings applied to the front surface of sunglass lenses to reduce the amount 

of light entering the eye. This makes them especially beneficial for activities in 

very bright conditions, such as snow skiing on a sunny day.

The mirrored sunglasses associated with state troopers are one example of a flash 

coating. The technology has advanced, however, so that today's choices in mirror 

coatings include all colors of the rainbow, as well as silver, gold and copper metallic 

colors. Hot pink, blue — almost any color is available.

Choosing the color of a mirror coating is a purely cosmetic decision. The color of the 

mirror coating you choose does not influence your color perception — it's the color 

of the tinted lens under the coating that determines how mirrored sunglasses 

affect your color vision.

Gradient lenses are tinted from the top down, so that the top of the lens is darkest. 

These lenses are good for driving, because they shield your eyes from overhead 

sunlight and allow more light through the bottom half of the lens so you can see 

your dashboard clearly.

Double gradient refers to lenses that are also tinted from the bottom up: 

The top and bottom are darkest and the middle has a lighter tint. 

Double gradient lenses are a great choice if you want sunglasses that aren't too dark, 

but shield your eyes well against bright overhead sunlight and light reflecting off 

sand, water and other reflective surfaces at your feet.

Photochromic lenses adjust their level of darkness based on the amount of UV light 

they're exposed to. Read more about photochromic lenses.

What about sunglasses  blocking infrared rays? Infrared rays are located  just past the red portion  of the visible light spectrum.  Though infrared radiation  produces heat, most experts  agree that the sun's infrared  rays do not pose a danger to  the eyes.

Which lens color is the best?

Lens color is a personal choice and doesn't affect how well sunglass lenses protect 

your eyes from UV light. Gray and brown are popular because they distort color 

perception the least.

Athletes often prefer other tints for their contrast-enhancing properties. 

For example, yellow lenses are popular with skiers and target shooters because 

they work well in low light, reduce haze and increase contrast for a sharper image.

Are impact-resistant lenses necessary?

The FDA requires all sunglass lenses to be impact-resistant. If you play sports or 

wear sunglasses on the job, you might want to consider ultra-impact-resistant 

polycarbonatelenses for even greater eye safety.

Do I still need those "UV Protective" sunglasses if my lenses are real dark?

Yes! Most people believe that the darkness of the lens is what protects their eyes. 

The degree of darkness has no effect on UV rays. For adequate protection, you need 

to buy sunglasses that indicate they block 100 percent of the sun's UV rays.

Are the more expensive sunglasses of better quality?

Not necessarily. While expensive sunglasses usually are high quality, you can also get 

a good pair for under $20 if you're a careful shopper. Just make sure to check that the 

lenses provide adequate protection from UV light and are free of distortions.

You can also take them to your eye care professional to have the lenses metered to 

determine the amount of UV that passes through the lenses. That way you can be sure 

you are getting the most from your sunglasses.

Children don't need sunglasses, do they? Children's sunglasses are essential.Children are at particular risk because they're in the sun much more than adults, and their eyes are more sensitive as well. UV damage is cumulative over a person's lifetime, which means you should begin protecting your child's eyes as soon as possible. Most parents would not allow their children to go outside without shoes, yet many seem unaware of the need to protect their children's eyes.

I wear glasses. What options are available to me?

You can buy prescription sunglasses or glasses with photochromic lenses (which change 

from clear to dark) from your eye care practitioner. Clip-ons may be a less expensive 

option, and can be bought at the same time as your regular eyeglasses to perfectly 

match the frames. Some eyeglass frames include sun lenses that magnetically attach to 

the frame. This gives you the convenience of clip-on sunglasses with less risk of scratching 

your prescription lenses.

Do those sunglasses for specific sports really make a difference?

Yes. Sports eyewear in general tends to be safer than regular sunglasses because the 

lenses and frames are made of special materials that are unlikely to shatter if struck and 

can give you the benefits of both sunglasses and protective eyewear.

Also, certain lens colors in performance sunglasses can enhance your vision for certain sports; 

brown, for example, is popular with golfers because it provides nice contrast on those very 

green golf courses.

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