As the surface of sunglasses is heated or scratched, the lens’ ability to block UV rays weaken. The worst thing to do to a pair of sunglasses is leave them inside a car on a hot summer day.
If unsure of how well your sunglasses protect the eyes, visit the closest optical store for a check-up. Optical stores have gears to measure a sunglasses’ transmissivity of UV rays.
The machines spell out in digitized numbers how much UV rays the tinted lenses let through, and the lower the number is, the better job the sunglasses are doing. If the transmissivity is over 20 percent, it’s barely doing any work to protect the eyes.
A pair of sunglasses lasts longer if kept inside its own exclusive case draped in cleansing cloth. Also, clean the sunglasses right after outdoors use. Get rid of the dust on the surface of the lens, wash with neutral detergent and dry them completely at room temperature before reusing them the next time.
Colors of the lens are crucial to the eye, and the most common color black is the most advisable choice because it consistently blocks every light for daily use.
A brown lens is useful for cloudy days or during hiking. A green lens is good for the occasions when the wearer has to look at one place for a long time, such as when driving long distances or going fishing. An orange lens is suitable for people driving at night.
Sunglasses UV transmissivity does not rest on the color density of its lens, nor its price tag. If you pick the right pair for the right occasion and take good care of it, your sunglasses will last longer.
By Kim Soo-bin, Intern Reporter (firstname.lastname@example.org)