So how do sunglasses work?

There are two reasons to wear sunglasses. The first reason is
if you don't like the bright sun shining in your eyes, as the
dark surface of the sunglasses helps to block out bright light
and make the world appear darker. The second is that the sun's
ultraviolet rays can be harmful in the long term, causing all
sorts of problems with your eyes including loss of eyesight and
eye cancer. Good sunglasses protect against this, as their
lenses filter out most of the harmful UV rays.

So how do sunglasses work? The darkening effect is a very simple
one: looking at the world through tinted lenses makes it seem
darker to you - even though the effect is really just an optical
illusion, it can help you if exposure to bright sunlight tends
to give you a headache or cause you to squint.

The UV-filtering effect, however, is more complex. UV-filtering
lenses are coated with special chemicals that allow light to
pass through them, but reflect away UV. UV rays are basically
high-frequency light waves, which means that the chemical
structure has to be built to deflect higher frequency light
while allowing through lower frequency light. This is difficult
science, and the materials needed to do it are expensive.

The most complicated sunglasses of all are prescription
sunglasses. These are sunglasses that not only protect from
light and UV, but also work like normal glasses to correct your
eyesight. For this to work, it requires that normal
vision-correction glasses are taken, tinted and coated with
UV-reflecting chemicals - a complicated three-step process.
However, all the ingredients work together flawlessly, to
produce sunglasses that are wearable by people who need their
vision corrected all the time. It is even possible to buy clear
tinted lenses that fit over the top of your normal glasses,
effectively a do-it-yourself way of making prescription
sunglasses.

About the author:
John Gibb is the owner of href="http://www.Sunglasses-guidance.info">sunglasses guidance
, For more information on sunglasses please check out
http://www.Sunglasses-guidance.info


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