Technical Information

Lenses

Type of lenses

Quality sunglasses offer a polarized lens. All of EARTH sunglasses are polarized and we use the Triacetate Cellulose (TAC) polarized process. The TAC process uses a multiple layer production.

Polarized lenses have the benefit of filtering out reflected light and glare off water, pavement and snow. TAC polarized lens are superior for fishing, boating, driving or any other glare intensive activity. TAC polarized lenses are the best ways to eliminate glare and UV light. Polarization is achieved by shutting out 100% of undesirable light and allowing 100% of desired light through the lenses.

Multi-layer composite complies with the international sunglasses lenses standard and UV400 UV sunglasses lenses standard. Thus, the polarized lenses can fully protect eyes. The first layer is a polarizing layer; core of the lens as it provides more than 99% of the polarizing effect, which can effective absorption of glare. Second and third layer for bonding, can effectively resist the cutting, baking, baking bend, cut pieces, tests of withstanding harsh environments. The fourth and fifth layer for UV-absorbing layer; absorbing 99% of UV-ultraviolet rays. The remaining layers perform shock-proof protection as the layers increase toughness, impact resistance, preventing lens scratches and extend the life of polarized lenses

Layers of protection

lenses diagram

TAC produced lens are ultra-light and are highly impact resistant.

TAC polarized sunglasses lenses are effective cutting strong light, reflection and scattering light. It makes light rays become parallel. TAC polarized lenses makes the scenery more clear and soft. EARTH sunglasses have zero distortion of scenery and the feeling of vertigo.

 

Types of Hinges

Barrel Hinges

The most common type of hinges you will encounter are Barrel hinges. These hinges work similarly to door hinges and are one of the oldest types of hinges found on glasses. Standard hinges are made up of barrels that fit into each other like a zipper with a small screw that slides into the middle to keep the barrels in place. This allows the temples to move in and out while still keeping them firmly attached to the frame front.

Flex Hinges

The second most common type of hinges that you will encounter are Spring Hinges (or “flex hinges”). These hinges are equipped with a small spring that affords the arms a greater range of movement and does not limit them to the traditional, 90 degree angle. These hinges provide greater comfort for the wearer and are more able to withstand everyday use.

Important consideration for hinges:

The hinges on eye wear is often overlooked. The hinge that connects the frame to the arm is extremely import to the life of the eyeglasses. People tend to look at design, the quality of the lens and cosmetic appearance on face. However if the quality of the hinge is questionable the value of the glasses are limited. EARTH always use high quality stainless steel hinges. We want to assure a long time use of our eyeglass frames.

 

Glossary of Eyeglass Frames

A

Acrylic plastic lens:
a lightweight and inexpensive lens option.
Anti-reflective (AR) coating:
a thin coating applied to lenses in order to reduce the amount of reflected light and glare that reaches your eye, as well as the amount of glare visible to others looking at your lenses.
Aviator:
a style of sunglasses made popular by pilots that typically have a metal frame, top bar, and large, tinted lenses. Think Maverick in Top Gun. Click here to shop our selection of aviators!

B

Base tint:
a dye embedded in sunglass lenses that creates the color you see when you look at the backside of your shades.
Bridge:
the area that arches up between the lenses over the nose and supports the majority of the weight of the glasses.
Browline:
retro sunglasses with a heavy browline and thin lower rims. Celebrities like Bruno Mars and Robert Pattinson are often seen sporting this style.

C

Carbon fiber:
a distinct material used for sunglass frames that is very strong and hard to adjust. Carbon fiber sunglasses are ideal for both the adventurous and the accident-prone.
Case:
a hard protective box that fits to standard sunglasses size and is intended to keep your glasses from being scratched, bent, broken, or sat on.
Cat eye:
a retro feminine sunglass style that is distinguished by its upswept outer edges. Popular with 1950s style icons such as Audrey Hepburn and Marilyn Monroe, modern day celebs, and anyone who wants to feel like a celebrity?
Clip on:
sunglass lenses that clip (or attach) onto your prescription eyeglasses and provide protection from the sun.
Coating:
a treatment applied to the surface of your lens to provide additional protection, utility, or style.
  • Anti-reflective coating reduces the amount of distracting reflections bouncing off of your lenses. This type of coating is often applied to curved lenses.
  • Hydrophobic coating acts as a waterproofing shield by sheliing water and sweat that your sunglasses may encounter. This also reduces spotting that may otherwise occur on the lens surface.
  • Mirrored coating gives lenses the appearance of a mirror and can help reduce glare and bright light.
  • Scratch-resistant coating helps prevent polycarbonate and other plastic lenses from scratching.
  • Photochromic coating automatically darkens and lightens the tint of your lenses when the light changes.

D

Diopter:
the unit of a lens’s refractive power, equal to the reciprocal of the lens’s focus length in meters. Used as a measurement to prescribe corrective lenses.
Driving sunglasses:
a style of sunglasses designed to decrease eye strain on drivers thanks to lenses that reduce glare and enhance the driving experience.

E

Earpiece:
the plastic covering encasing the portion of the frames that rests on top of the ear and provides additional comfort. Most commonly seen on metal frames.
Endpiece:
the part of the frame that connects the lenses to the temples.

F

Fit overs:
these sunglasses are for people who already wear corrective lenses. They’re larger than your regular glasses so they can be worn right over them.

G

Glare:
a condition caused by bright light from a direct or indirect light source (like the sun’s reflection off the water) that causes difficulty in seeing.
Glass:
a common material used for lenses that offers excellent clarity and resistance to scratching.

H

Hinge:
the folding part of the frame that connects the rim to the temples and allows the temples to lay flat along the inside of the frame.

I

Interchangeable lens:
lenses that can be swapped out of a pair of sunglasses to provide different looks or lens benefits.

L

Lens:
the transparent glass or plastic part of sunglasses that you looks through. Lenses protect your eyes by blocking UV light.
Lens size:
the width of a lens in millimeters, measured at its widest point.

M

Melanin polarized lenses:
lenses with a highly protective treatment that works against UV radiation, blue light, and glare.
Metal frames:
frames made from base metals, copper, or nickel alloys that are later plated with fine metals, such as gold, to give them a rich finish.

N

Nose pads:
soft plastic pieces that are attached directly to the frame or to the pad arms. They help to keep the frame in its proper position on your face, while also ensuring that the shades fit comfortably.

O

Optical clarity (acuity):
the ability of a lens to deliver a sharp image to the eye.
Oversized:
overly large sunglasses with very large lenses and frames. Often spotted on A-list celebs, they come in a variety of styles and prints. Plus they work well for extra sun coverage.

P

Pad arms:
these hold the nose pads in place, but still allow adjustments to help the pads better conform to your nose.
Peripheral vision:
the edges of your visual field.
Polarized lenses:
lenses with a special coating that increase visibility by filtering out horizontally-reflected glare. While useful for everyone, polarized lenses are especially beneficial for senior citizens, diabetics, those with sensitive eyes, or anyone who spends hours in the sun or snow. Teens and children under 18 should also jump on the polarized lens trend to protect their eyes.
Polycarbonate:
an extremely strong plastic used for sunglass frames that weighs little and is impact-resistant, making it an ideal selection for those who need a tough and rugged style.

R

Reading sunglasses:
a style of glasses that combine the power of reading glasses with the protection of sunglasses, making them the perfect style for outdoor reading.
Retro Square:
an iconic sunglass style characterized by its slightly trapezoidal shape. Suited for both men and women, retro square frames became popular in the 1960s and remain one of the most sought-after styles today.
Rim:
the part of the eyeglass frame that holds the lenses in place and crosses the top of the nose.
  • Full rims are the style most typically found on sunglasses where the lens is completely encased in the rim of the frame.
  • Semi-rim styles are those in which the lens is encased only at the top of the frame.
  • Rimless styles lack a rim entirely. Instead, the lenses are joined together by the bridge and the temples are also attached to the lenses.
Round:
a sunglass style characterized by its round lenses. Round sunglasses have proven to be a timeless style.

S

Screws:
tiny metal fasteners used to connect the temples to the rims and to hold the nose pads in place on eyeglass frames.
Shield:
distinctive sunglasses that are defined by their signature one-piece lens. Their frames can be thin, thick, or anywhere in between.
Silicone:
a type of flexible and comfortable plastic that is commonly used in nose pads.
Stainless steel:
a type of steel commonly utilized in wear. Stainless steel frames can be very thin while still maintaining their strength and flexibility.

T

Temples:
“arm” pieces of the frame that extend over, and sometimes behind, the ears to help hold the sunglasses in place.
Temple tips:
plastic coatings that often cover the ends of the temples near the ears to provide comfort. Commonly used with metal frames.
Tints:
colors you can apply to your lenses to enhance clarity in different lighting conditions, increase visibility, and reduce glare. For example, brown-tinted lenses enhance depth perception when there is little light. Tinted lenses are not only fashionable, but functional.
Titanium:
a type of metal alloy that is very strong and used to make sunglasses that are lightweight and durable.
Top bar:
also known as a “sweat bar” or “brow bar,” this is the reinforcing bar that crosses between the two lenses at the top of the frame, on some metal styles.

U

Ultraviolet (UV) rays:
energy emitted by the sun that you can’t see or feel. Extended exposure to UV rays can increase your risk for skin cancer and cause damage to your eyes, making UV protection an important feature to look for in a pair of sunglasses.
UV filter:
a lens coating that fights UV radiation and protects the eyes by filtering out the sun’s harmful rays.

V

Visible light:
the part of the sun’s energy that one can see. It is made up of a spectrum of colors: red, orange, yellow, green, blue, and violet.

W

Wrap around:
a type of sunglass frame that curves around the head, from the front to the side. Wrap arounds provide better sun protection than any other type of sunglasses.