Sunglasses come in a bewildering array of choices; never have 
there been so many options to select from. With all the variety 
you’ll want to know ahead of time what the differences are 
between tinted, reflective, photochromic and polarizing lenses. 
Of course the style of frame and size of lenses will be obvious 
differences when shopping for sunglasses. It will also be 
important to know exactly what purpose you’ll be using your 
sunglasses for.

Sunglasses allow for us to see easier in the bright light. Some 
glasses protect against ultraviolet (UV) rays while reducing 
glare and giving protection from physical damage that may be 
caused to the eyes. Everyone is at risk for sun related eye 
problems. People who spend long hours in the sun during work or 
outdoor activity are at higher risk, than someone who is working 
indoors all day long. Other people may be at higher risk of eye 
damage if they are on certain medications such as; tetracycline, 
birth control pills, diuretics and sulfa drugs.

Ultraviolet light can damage both the cornea and retina, so with 
a good pair of sunglasses the UV can be eliminated from entering 
the eye completely. Whatever sunglasses you select they should 
provide the most possible UV protection possible. It’s good to 
find a pair of glasses that block the sun from all angles, best 
achieved with a large framed pair that wrap around the face. 
Purchase sunglasses that block both the UVA and UVB rays, your 
lenses should indicate this when buying them, if they don’t 
specify what protection is offered it is best not to buy them. 
On top of wearing sunglasses it is a good idea to wear a wide 
brimmed hat.

Manufacturers use different colors of tints to produce specific 
results for a variety of sunglasses needs. The color of the tint 
will determine the parts of the light spectrum that will be 
completely absorbed by the sunglasses. Yellow or gold tints 
reduce there opposite color, which is blue while allowing other 
lights to pass through. Blue lights tend to create a glare 
otherwise known as blue haze. Gray tints are generally used as 
an all- purpose tints reducing the overall brightness with the 
least amount of color distortion. The gray lenses are a good 
lens for general use and driving. Brownish and amber tints are 
another example of good all-purpose glasses. They reduce glare, 
absorbing blue and UV rays. Blue and violet have been shown to 
contribute to cataract formation. Purple and rose tints are 
great choices for water sports or golfing as they offer contrast 
of objects against a blue or green background. Green tints are 
another popular option as they absorb some blue light while 
reducing glare.

To recognize a pair of reflective sunglasses they will be the 
pair with the mirrored look. Reflective sunglasses use a 
reflective coating called a half-silvered surface as it is 
applied in a very sparse, thin layer. The reason the process is 
called half-silvered is because the reflective molecules applied 
over the glass is distributed evenly but only half the glass is 
covered because of the speckled process. Thus the surface will 
reflect only about half the light striking the surface, letting 
the other half go through the glasses. Many styles of mirrored 
glasses come in gradient forms that have additional protection 
on the top part of the glasses with less protection at the 
bottom of the lenses. Mirrored sunglasses are unfortunately 
easily scratched so extra caution must be used to keep them 
protected.

Both sunglasses and prescription eyeglasses that darken when 
exposed to the sun are known as photochromic (or photochromatic) 
sunglasses. The special lenses work by using a chemical reaction 
with the UV radiation. The lenses have millions of molecules of 
substances such as silver halide or silver chloride. When the 
lenses are exposed to UV rays from the sunlight, the molecules 
embedded in the lenses undergo a chemical reaction causing them 
to absorb light thus darkening. Without the UV light, the lenses 
go back to their original state, it should be noted that the 
lenses would not darken in the car as the windshield block out 
most of the ultraviolet light. Most of the photochromic lenses 
do however have a bit of tint included in them, so they will 
still work while driving.

It helps to know a bit about polarization to understand why 
polarized sunglasses work. Polarization happens when radiation, 
especially light through being transmitted, scattered, refracted 
or reflected is restricted to vibrate in only one particular 
direction, it can occur both naturally and artificially. An 
example of natural polarization is when you look at the ocean 
or a lake, the glare off the surface is a result of the light 
that did not make it through the filter of water, therefore you 
cannot see below the surface. What polarized lenses does is 
allows the vertically polarized light to enter from most 
horizontal surfaces such as highways and water. A good test 
to see whether sunglasses are polarized or not is to find a 
reflective surface and with the glasses in front of the surface 
you want to view, slowly rotate the glasses checking to see if 
the glare diminishes, if it does the glasses are polarized. 
Photographers often use special polarized lenses atop their 
ordinary lenses to avoid unnecessary glare from surfaces.

There are a few extra features of sunglasses that will add to 
the quality of your lenses. Scratch-resistant coating is 
achieved by applying a thin durable film on the surface of the 
lenses; this extends the life and safety of your glasses, as 
it’s almost impossible to wear a pair of glasses with a scratch 
on them while trying to see properly. Anti-reflective coating 
reduces what is known as back-glare, a result of light hitting 
the back of the sunglasses and bouncing into the eyes. Lastly 
the most popular coating is the ultraviolet or UV coating. Some 
of the most serious of eye problems can be linked to UV light, 
both UVA and UVB. A good UV coating on your sunglasses will 
eliminate UV radiation, it is important to check that your 
glasses filter out one hundred percent of both UVA and UVB, 
there should be a label on your sunglasses stating this 
information.

Sunglasses come in a myriad of design, color choices and styles. 
Popular designers offer glasses in prescription, men’s, women’s, 
sports and junior varieties. A suggestion when purchasing 
sunglasses is to try and select a pair that blocks the light 
from all angles, preferably one that wraps all the way around 
the face, this is if you want the ultimate eye protection. Of 
course with all the choices available you’ll most importantly 
select sunglasses that block both the UVA and UVB radiation in 
a style that provides comfort and the right fit.

Whatever sunglasses you decide on wearing you will feel safer 
knowing you are eliminating harmful rays from entering you’re 
eyes. By properly taking care of you’re eyes you can hopefully 
avoid problems such as cataracts, cancer of the eye or 
photokeratitis (sunburn of the retina) and macular degeneration 
(which is the leading cause of blindness in people over 65). 
Paying a little extra for a pair of sunglasses with one hundred 
percent protection is a smart investment.