Do Sunglasses lenses wear out?


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When our patients come in to our office, we want to make sure we practice preventive eye care in their yearly comprehensive eye exam, so people don’t outlive their vision.  The age old saying “carrots are good for your eyes.” is true but many things protect our vision throughout our lives.  Foods help protect our vision and are very important.  We discuss this as part of the eye exam and explain to our patients why they are important.

Food groups such as green leafy vegetables and colored vegetables provide protection to our eyes whether we are exposed to UV or not.  The other layer of vision health protection are glasses with lenses that provide Ultraviolet protection.  How do we protect our eyes when indoors or outdoors?  What comes to mind?  Outdoors would be sunglasses.  Indoors would be clear lenses that have Ultraviolet protection as well and preferably with a blue light absorption component.  Most people don’t know the importance of UV protection indoors.

Indoors and outdoors we need Ultraviolet protection.  Don’t be duped by seeing and getting sunglasses you see have UV protective stickers because they may or may not be and can possibly do more harm than good even if you like the way you look in them!:)  Do you ever see UV stickers on pickup readers?

Do Sunglasses wear out?  Does the UV protection in glasses for indoors wear out?

Exposure to the sun may deteriorate your sunglasses over time and the lenses may become lighter in color and alter their full need for vision protection.  It may also diminish the impact resistance of lenses which means how ‘shatterproof’ the lenses are.  Current national standards require that sunglasses provide levels of UV protection.  But some slip through to the consumer that are not.

The aging test on Ultraviolet protection in lenses was done in Europe, Brazil, New Zealand and Australia.  These were countries that they felt UV exposure might be at its greatest based on their proximity to their regions and equator.  The test exposes sun glasses and Indoor glasses to a simulator for 50 hours.   The lamp exposure is equivalent to two days in a natural environment on a summer’s day, or four days in winter.

Interesting to find out that most Brazilians replace their sunglasses every two years. Tests for ultraviolet protection was done to see how UV safe the sunglasses are to wear for these two years.  The test assumed that the people wore glasses and/or sunglasses 2 hours/day.

Exposure will vary among world latitudes, with tropical countries being of most concern, as UV indexes are extremely high in summer and remain high in the winter. Therefore, sunglasses worn in the southern hemisphere may need replacing more often than in those worn in the northern hemisphere.

“The study calculations were carried out in 27 Brazilian state capitals and data for 110 national capitals in the northern hemisphere were also included. Calculating the equivalence of the simulator to natural light is an estimate because when an individual wears sunglasses, the lenses are not directly exposed to the sun, as they are usually worn in the vertical position.”

The studies did show that UV protection in lenses did diminish with time and light exposure in and out of doors on cloudy and sunny days.

Lenses should provide adequate UV filters, because insufficient protection could lead to deterioration to the cornea which is the windshield of the eye as well as to the internal structures of the eye. This UV exposure was the potential cause of edema (swelling of the eye which can distort vision), pterygium (growth of pink, fleshy tissue on the white of the eye that can interfere with vision), cataract (clouding of the lens of the eye) and retina damage in the form of macular degeneration( permanent loss of central vision).

Be an advocate for eye health and eye exams!

People ask if they need to wear sunglasses in non summer months or cloudy days and we tell them definitely yes.  They then ask why do I need to protect my eyes inside as well.  It is because of the exposure we have to ultraviolet light in the blue light color spectrum. Where does that come from indoors?  It comes from our light bulbs, our phones, our kindles, our computers and electronic pads.  The bottom line is that natural and non natural light damages our vision.

The confusion is obvious.  The word sunglasses denotes their need only when the sun is out.  Most of us think of the sun being out when it is summer time and the sun is out most of our waking hours and more hours that time of year.  Indoor glasses are not thought of in terms of them needing to be protective to our eyes as well.  I know we see UV protection stickers on Sunglasses in stores that people pickup but have you ever seen pickup reading glasses with a UV sticker.

I found this story interesting and thought it would incorporate what we preach in our practice about UV exposure.  I think people would better understand the need for UV protection if we designated its level of protection on clear lenses and I’d like to change the name for Sunglasses to “Outdoor Glasses! ,” b/c they should be worn any season when someone is outdoors on cloudy or sunny days.

This story was one we practice and when we found the story on the loss of UV protection in aging lenses we thought it would be good to share.

Thanks                                         Drs. Warren Johnson and Do Nguyen




About Eyewear Gallery

Eyewear Gallery was established 30 years ago and our office likes to write about many topics that are related to eyecare, glasses and stories that we hope you enjoy. We write about your vision, health and educational facts as well as some fun information. We pride ourselves in medical eyecare and designer eyewear and have received the Peoples Choice Award more than once. We have designer frames such as Lunor, Tiffany, Oliver Peoples and Tom Ford. We also have non designer eyewear and cater to all ages. We stock alot of sunglasses such as Oakley, Wiley X, Costa del Mar, Ray Ban and Maui Jim for sports and outdoor fun. Eyewear Gallery is also known as one of the few Custom Sports Sunglass providers in the USA in both prescription and non prescription. Please visit our website Thanks for visiting and following our blogs.
This entry was posted in Blue light protection, Carrots are good for your eyes, Indoor Glasses, sunglasses, Uncategorized, UV protective sunglasses and tagged , , , . Bookmark the permalink.

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