Celebrating our 10th year as an on-line performance eyewear leader!
Sunglass Frame and Lens
Technology
FRAME MATERIALS
Most
high-end sunglass frames are constructed of two basic types of
material---plastic compounds and metal alloys. Each material has distinct
benefits, and the expected use of the glasses should guide your initial choice
between the two. Generally speaking, metal frames tend to be "dressy", while
plastic frames are best for casual and sports use. Metal frames will likely have
a separate nose piece; most plastic frames will not. Listed below are several
different materials used by the manufacturers we
represent:
GRILAMID-Nylon compound. Light weight coupled with
extreme flexibility and toughness. Highly resistant to sunscreens and other
personal-care products (does not apply to painted or plated frames, which can be
easily damaged by long-term exposure to these chemicals). Allows the use of
integrated hidden hinges. Adjustments usually not an option due to the
material's flexibiliy (in simple terms, this means that the frame either fits or
it doesn't).
ACETATE-Also refered to as Zyl Acetate. High-quality
material used for clears, crystals, fades and other high-fashion polished
designs. Frames usually have a smooth, dense finish. Can be used in both
painted/plated frames and in through-and-through colors. May require adjustments
to fit the wearer due to limited flexibility (frames will likely need to be
heated for adjustment---you will want to contact a local optical office for
assistance).
PROPIONATE-Acetate-based material used in most Spy
Optic fashion frames. Hard, polished surface. May have wire cores in the temples
allowing for personal adjustment---frame heating will usually be
required.
NYLON-Cellolose (plastic based) compounds used by many
manufacturers. Strong, lightweight and durable, nylon can be used for solids,
fades and painted/plated frames. Likely the most common material used in
performance eyewear frames. Adjustments may be possible with frame
heating.
METAL ALLOYS-Best for casual or fashion use (not for
sports or other active pursuits). May be fitted with spring hinges, which
provide great comfort but less "grip". Not as forgiving as plastic-based frames
if dropped, sat on, etc. Adjustable earpieces and nosepads provide the
opportunity for a true custom fit. Produced in full-rim, half-rim and virtually
frameless designs.
FRAME FINISHES-Sunglass frames are produced in
both "Gloss" and "Matte" finishes ("Matte" is best described as a flat or no
gloss finish). All glasses should be cleaned regularly to avoid damage from
tanning lotions and other personal-care chemicals.
LENS MATERIALS
Sunglass lenses are produced in glass and various
plastic compounds:
GLASS-Provides superior optics and scratch
resistance, but may crack or shatter if dropped, struck with a hard object, etc.
Not for use in sports or other active pursuits. Some manufacturers are now
producing thinner glass lenses, resulting in substantial weight savings (Smith,
Maui Jim).
CR39-Hard plastic resin developed
by PPG during WWII. Much lighter (about 50%) than glass of equivalent thickness.
Prone to scratching unless treated with a scratch-resistant coating (most
manufacturers do coat their lenses). Used for most colored, fade and gradiant
lenses due to ease of tinting.
POLYCARBONATE-The most
impact-resistant lens material currently available (also used in bullet-proof
glass). Can be produced thinner and lighter than either CR39 or glass. Prone to
scratching unless treated (as with CR39, most manufacturers do coat their
lenses). Difficult to tint, so generally not used for colored, fade or gradiant
lenses. Most quality solid-color lenses (grey, grey-green or brown) produced by
our manufacturers are made of
polycarbonate.
POLARIZATION-Available in either glass, CR39 or
polycarbonate lenses. A Polarizing filter is designed to cut glare (intense
light reflected off of a flat horizontal surface---water, snow, asphalt,
concrete, etc in front of the wearer). Has no bearing on ambient (non-reflected)
sunlight, lens color, tint darkness, etc (a clear lens could be produced with a
Polarizing filter). Users: skiers, snowboarders, boaters, fishermen, drivers in
both bright winter and summer conditions. Usually offered in a limited number of
frame colors (except Maui Jim, whose models all use Polarizing
filters).
FRAME SHAPEShown
below are examples of the three basic frame shapes as described on our website
("Minimal Wrap", "Semi-Wrap" and "Full Wrap"). "Wrap" simply refers to the
amount of curve in the frame. These overhead photos clearly show the difference
in wrap between three frame designs of about equal overall width. The amount of
wrap in a frame will affect how the glasses fit different face shapes and
sizes---generally speaking, full-wrap frames will fit closer to the face than a
semi-wrap, which, in turn, will fit closer than a minimal wrap. 
FRAME SIZES
Most sunglass frames
fall into 3 general size categories having to do with their overall width
(Small, Medium and Large are the way we describe them on our website). These
descriptors do not necessarily apply to the size of the lenses (for example, a
Medium width frame might have Large oversized lenses). Small frames are best for
narrow faces, Medium frames tend to fit most average-width faces, and Large
frames work well for wider faces.
Both the frame size and frame wrap
should be considered when selecting a sunglass style for your particular face
size/width and expected product use.
UV PROTECTION
Studies show that long term exposure to UV rays may cause
eye diseases, including cataracts. In addition, short-term exposure can cause
temporary conditions such as "snow blindness", Ultraviolet radiation can be
divided into three categories.
UVC (200 - 290
nm)
UVC is absorbed by the earth's atmosphere and
never reaches your eyes.
UVB (290 - 320
nm)
UVB is a physically painful form of ultraviolet
radiation. These are the sun's "tanning rays" which are absorbed by the cornea.
Exposure to UVB can temporarily damage the cornea.
UVA (320 - 380 nm)
UVA rays are absorbed by
the lens of your eye. The resulting damage heals slowly, if at all. About one
percent of all UVA rays penetrate the retina, which cannot repair
itself.
According to factory documentation provided by each of our
manufacturers, all sunglass products shown on our website provide 100%
protection from both UVA and UVB rays.
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