What are the disadvantages of progressive lenses? | KOALAEYE OPTICAL

What are the disadvantages of progressive lenses?

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The development of glasses

In 1451, Nicholas of Cusa of Germany invented a lens that was thinner in the middle and thicker at the end to help short-sighted people. In 1727, Edward Scarlett, an English optician, invented modern frames that could be worn over ears and noses. Benjamin Franklin, an American scientist, and philosopher invented bifocals, which divide the lenses into far and near parts. The two lenses are held together by a metal frame. Frame construction has improved over the centuries, and today frames have come in different kinds of styles and designs. Unbreakable lenses were invented in 1955, and in 1971 a new type of lens combining plastic and glass properties was invented.


Allen OTG Safety & Shooting Glasses

Chemistry LABS and carpentry aren't the only applications that need safety goggles on top of glasses.These Allen OTG glasses work better on indoor shooting ranges. You can use these comfortable safety glasses to better focus your front view. Unlike the other OTG safety glasses on the list, these glasses lie flat on the side of your head and are specially designed to fit comfortably under the earmuffs without breaking the noise seal.



Points to Note When Buying Saddle Bridge Glasses

Ask yourself the following questions: Is it worth buying saddle bridge glasses? What are the benefits of buying saddle bridge glasses? Which saddle bridge glasses are better on the market at present? Where can you find information about saddle bridge frames? It includes buying guides, rating sites, word-of-mouth recommendations, online forums, and product reviews for saddle bridge frames. These studies are important to ensure that you get the best saddle-bridge frames possible. Make sure you only use trustworthy websites and sources.


Testing of aspheric lens

The optical axis of the optical center just overlaps with the visual axis of the eye, which is the most ideal state. Because the light from the edge cannot form a focus on the optical axis, when the optical axis does not overlap with the visual axis (the difference is greater than 2mm), such unclear and scattered imaging results will occur. When choosing frames and aspheric lenses, you need to ensure that they fit correctly, to achieve the best visual and decorative effects. Simply put, due to the special design of the lens, we found through a calculation that the optical center should move down 1mm higher than the pupil for every 2° increase in front inclination angle. Otherwise, the wrong pupil height will cause the lens to look like astigmatism, and cause discomfort. For glasses with aspheric lenses, there must be an inclination angle after wearing. The specific angle varies from person to person.



Features of pure titanium glasses frame

Due to the lightweight (ordinary nickel-based alloy frame weight 48%-60%), high strength, corrosion resistance, surface easy coloring, beautiful and durable features of spectacle frame made of pure titanium, they have been loved by most consumers. But the elastic modulus of pure titanium is higher (about 120GPa). The temples of the frames made from them are not elastic enough. After wearing the glasses for a period of time, the temples of the glasses need to be adjusted due to the relaxation of the stress. The processing plasticity of titanium metal is worse than that of other metal materials, so the processing technology of its wire is difficult. The surface quality is difficult to control, and the technical content is high. The surface quality of pure titanium wire produced by a few domestic manufacturers is poor.


Diamond-shaped face with irregular glasses

A diamond-shaped face is more difficult to choose frames because facial features are more distinctive. When choosing glasses, you should also choose more distinctive ones to modify your face. Irregular glasses, such as hexagonal or pentagonal glasses frames, can be selected. The fashion sense is particularly strong. It looks like a little girl's vision and has a good modification effect.


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For collection

Glasses' material and styles are constantly updated. It is more and more light and more beautiful. Early glasses may have become antiques. You might as well collect your retired glasses according to the time and story, and attach the tragic history of the glasses. Perhaps many years later today will become a beautiful memory. You might as well try the nostalgic and literary style.

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