Polarized
Lenses
These lenses are especially
important for outdoor people that require precise vision with minimal glare.
Polarized lenses are
unique lenses that work similarly to a Venetian blind. A
blind only lets in light at certain angles, which is how a polarized lens works.
With the removal of the sun’s glare, objects
become more distinct and are seen in their true colors. Reduced
glare off water, roads, and other objects make the polarized lens a favorite for
water sports, fishing, cycling and driving.
Normal Glare without Polarized Lenses
Glare is Eliminated with Polarized Lenses
- The density of color remains the same (see Photochromic lenses regarding variable tints)
- Density of color can be dark(C) or light(A). Light density is often used as an aid for night driving and with computer operators.
- Materials include plastic, high index plastic, glass and polycarbonate.
- Styles include single vision, bifocal and progressive lenses.
- Colors include Gray, Brown, and many others.
- Decreases driving
fatigue. Because much of the light reflected from large areas of pavement is
polarized, those who do a lot of driving will benefit from polarizing lenses.
- Comfort at the beach is increased. Sand and water are both sources of polarized glare, making these lenses especially appropriate. Colors are not bleached out. Reflected polarized light produces a veiling glare that may cause colors to appear less vivid. When glare disappears, color return.
- Bright snowy days are not as blinding. Snow is highly reflective. It is also polarizing. Those who are out working or driving in the snow will benefit from using polarizing lenses. (NOTE: Polarizing lenses may not be as advantageous for skiers as one might think. Skiers' heads tilt left and right, making the polarizing filter less effective when the frame is no longer oriented parallel to the ground.)
- They also 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.
- Overall, polarized lenses provide many wonderful benefits
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What
is the difference between a polarized lens and an ordinary tinted lens? |
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While
ordinary tinted lenses reduce brightness, only polarized lenses eliminate
glare. Polarization is achieved by placing a thin sheet of polarized film
between two layers of material. |
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How does a polarized
lens work? |
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Light rays vibrate in
many directions. As light passes through a polarized lens, the polarized
film channels the light rays to travel in the same direction; thus
eliminating unsightly glare, much the same way as a venetian blind channels
light. |
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Is it
possible to get a clear polarized lens? |
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No,
it is not. The amount of polarization a lens achieves is proportional to the
density of the film. The lighter the film, the less polarization a lens can
offer. Tinting a light polarized lens does not increase its polarity. It
simply darkens the lens and reduces brightness. To achieve maximum
polarization, you must use a lens that utilizes a dark (grey-c or brown-c)
film. |
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How thin can these
polarized lenses be surfaced? |
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The following are our
recommended center thickness': (a) normal cr-39tm polarized lenses - 1.8mm
(b) hi index polarized lenses - 1.7mm (c) polarized polycarbonate lenses -
1.5mm (d) glass polarized lenses - 3.0mm to 3.5mm. Glass
lenses require additional center thickness to accommodate the front wafer
and segment thickness. |
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What
determines a superior quality polarized lens? |
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The
three most important factors in grading a polarized lens are: (a) clarity of
the polarized film: inferior polarized lenses have a hazy film. (b) density
of the polarized film: lenses that possess a light film will not perform as
well as lenses that utilize a dark film. (c) film placement: in order to
achieve a cosmetically appealing thin pair of eyeglasses, the laboratory
must be able to know, with certainty, exactly where the polarized film is
placed in relationship to the front of the lens. |
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Can polarized lenses be
tinted and is tinting recommended? |
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Yes, plastic polarized
lenses may be tinted. We recommend a tinting temperature of 200 degrees or
less. We recommend tinting for those people trying to achieve a particular
color but it should be remembered that you do not increase polarization by
tinting. |
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Do
polarized lenses provide U.V. protection? |
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All
of our polarized lenses afford 99% absorption at 380 nanometers. |
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Can polarized lenses be
AR coated (antireflection coating)? |
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Yes, however, it is
unnecessary to AR coat both sides. We normally recommend coating only the
back side curve. |
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Are polarized lenses available with a photochromic material. |
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Yes, KBco has a lens called Transhades that is both a polarized and photochromic lens. |
Links:
eClips
KBco
NuPolar
Optima
Specialty Lens
Corporation
100 North Rancho Road, Suite #1
Thousand Oaks, CA 91362
Phone (805)495-3937 Fax (805)373-9843
E-Mail