Contact Lens Material - Hydrogels
The raw material of the hydrogel is called HEMA. HEMA is hydrophilic and has a water content of 38% by itself. By cross-linking with other polymers, the water content can be up to 80%. The world's first soft cloaking material (OttoWichterle, 1961) was made from HEMA, called PHEMA. Nowadays, most conventional hydrogels are made up of the copolymer of PHEMA and other monomers.
Editor's Pick: Polarspex Polarized Night Driving Glasses
The most popular product on Amazon is Polarspex's line of polarized sunglasses. A wide variety of finishes are available. You'll want to select Night Driving Yellow lenses for your night driving glasses. Affordable and stylish, these glasses feature a plastic frame, metal-reinforced hinges, and plastic polarized lenses designed to block BOTH UVA and UVB rays.
What Do the Numbers on Glasses Mean?
The first number on glasses frames is the eye size. It is the horizontal width of the lenses. In general, the number of eye sizes varies from 40 mm to 62 mm in most of the spectacle frames.
The second number is the bridge size. It is the distance between the lenses. Also, it is the bridge that rests upon your nose. Mostly, the size of the bridge on glasses frames would be from 14 mm to 24 mm.
The third number is the temple length. It is the length of the stems of the frame that rests upon your ears. It can be measured from hinge to the end tip of the temple. In general, the temple length in most cases is from 120 mm to 150 mm. The bridge and temple help the frame to comfortably fit on the face.
Meanwhile, if there are no numbers on glasses frames, do not worry. You can always measure your eyeglasses frame with a millimeter ruler. Sometimes, the tiny numbers are worn off or sometimes they are printed too small that you might have to use the magnifying glasses. If you have known the glasses numbers meaning, you can choose to measure them by yourself.
At the same time, to fit the glasses better, you can also choose to measure your face for glasses frames. After knowing the suitable size of glasses, you can choose to buy a pair of glasses online. Thus, Koalaeye Optical is recommended. It is an online glasses store and provides all kinds of glasses, sunglasses, and frames. What’s more, these glasses are stylish and cheap.
Beta Titanium Eyeglasses Rimless Flexible Optical Frame
These are Beta titanium rimless flexible optical glasses. Free delivery around the world is provided! Many colors like Gold, black, gray, red, brown, pink, blue, purple are available. They choose high-quality materials. There are high-quality photos and real customer reviews. They have different kinds of sizes, and affordable products are provided.
PRiSMA blue light blocking glasses
PRiSMA is a functional anti-blue light glasses brand introduced by Germany to the world. Since its establishment in 1993, PRiSMA has been selling well in 33 countries and regions around the world. They use OAR double-layer coating technology to reduce reflection and increase penetration index. Ensuring a high blue light barrier at the same time, they increase the color contrast, so you can see more clearly, and effectively relieve eye fatigue. The product can protect the retina and relieve visual fatigue. They regulate melatonin secretion or reduces visual stress.
Where to Buy Unbreakable Eyeglasses Frames?
From the above part, you have learned some unbreakable eyeglasses frames. So, do you know where to buy unbreakable eyeglasses frames? To buy them, Koalaeye Optical is strongly recommended. It is an online optical store, providing all kinds of eyeglasses, sunglasses and frames. So, from here, you can get the most durable eyeglasses frames.
Besides, these eyeglasses frames are stylish and come at a cheap price. If you buy them, the eyeglasses will be mailed to you with your great convenience. So, if you need unbreakable eyeglasses frames, try Koalaeye Optical.
Difference Between Driving Glasses And Night Vision Goggles
Polarized glasses are made according to the principle of the polarization of light. Night vision goggles are an auxiliary observation tool based on night vision technology with the help of photoelectric imagers. Driving glasses are made according to the lens polarized angle and radian, on the basis of the principle of precision optical design. They can only make good light pass through, and other light sources, like the strong sunlight, the glare of a light source like a car headlight is filtered, thus removing the interference of external light, to avoid the presbyopia, dazzling, and so on. Night-vision goggles are divided into two kinds: One is Night Goggles, and the other one is Thermal Goggles. Image intensifying night vision technology is a photoelectric imaging technology that enhances the faint target image illuminated by night skylight through night-vision goggles with an intensifier tube for observation.