How Do Polarized Lenses Work?
Light reflected from surfaces like a flat road
or smooth water is generally horizontally polarized. This horizontally
polarized light is blocked by the vertically oriented polarizers
in the lenses.
The result: a reduction in annoying and sometimes
dangerous glare.
There is some debate on the effects of polarized lenses on snow-covered
surfaces. Some experts say they can reduce the intense glare that
is caused by sunlight reflecting off snow.
Others purport that the lenses are not satisfactory
for sports such as downhill skiing because they may not provide
the contrast the eye needs to distinguish ice patches or moguls.
In addition, polarized lenses may also react
adversely with liquid crystal displays (LCDs) found on the dashboards
of some cars or in other places such as the digital screens on
automatic teller (bank) machines. The problem with LCDs is that
when viewed through polarized lenses from a certain angle, they
can be invisible.
However, for most other sports and activities,
polarized sunglasses can offer great advantages. And today, many
types of polarized lenses are available on the market.
Whether you spend your time boating or waterskiing,
inline skating or mountain biking, driving or jogging, polarized
sunglasses are an excellent choice.
Understanding Polarized Light and Polarized
Lenses
While they enjoyed only limited use among optical
professionals for many years, polarized lenses have become the
first choice for anyone interested in a comfortable and attractive
sun lens.
The principle of polarized light reduction is
best illustrated by thinking of a polarized lens as a Venetian
blind. The blind blocks light at certain angles while allowing
light to transmit through selected angles. Polarizing filters
are aligned 90° to the angle of the polarized light. As spectacle
lenses are designed to eliminate the polarized light in the horizontal
plane, the filter is placed vertically in the eyewire or eyerim.
This means that the filter must be properly aligned during surfacing
and edging layout, otherwise the filter will not work properly.
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