What Are Category 4 Sunglasses? | KOALAEYE OPTICAL

What Are Category 4 Sunglasses?

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Choose clear glasses with the right size for kids.

The choice of children's glasses should be based on the size of the child's face and the height of the nose. Most of the bridge of your child's nose is low, so you can choose an adjustable eyewear frame with a separate nose pad to avoid touching your eyelashes or wearing the glasses uncomfortably. If the frame is too small, the field of view will become smaller. The frame is too large, they are not stable, and the weight will increase. So children with glasses frame should be moderate in size.


Can the TR90 frame be changed?

TR90 material was originally made in Italy. It is difficult to color the frame, and usually, the color is painted on the outside. It can float in saltwater. It is suggested that the lens should be a water first to prevent overheating of the lens. Then, at the end of the nose, hinge, or the temple, carefully fold it in until it is comfortable to wear. You can use a household hair dryer to blow heat first, which can play the role of softening. Note that the hairdryer should be moved when heating, and do not aim at only one place. TR-90 is the most popular ultra-light material in the world at present.



The price of new lenses

The price of the new lenses depends on several factors, including if you have vision insurance. Another aspect to think about is that if your lenses need an anti-glare solution. If so, the lenses may be much more expensive. If you need eye exams and special lenses, the cost can be quite high. Scratched lenses are easier to repair. If you want your scratched lenses repaired by a professional, most opticians can pay very little.


How To Choose Better Night Driving Glasses?

Driving at night has a high accident rate because of poor visibility, blinding headlights, and fatigue. Now the market exists a few main glasses: sunglasses polarizing lenses, Glasses that use or mimic the first generation of patented technology. So how do you compare the options between driving and wearing glasses?

Night driving lens is relatively special compared with daily driving lens, not only to prevent strong light and see the road more clearly. According to the national motor vehicle driver special glasses standards, QBT 2659-2004 daily light transmittance should be more than 8%, night light transmittance should be more than 75%. Be sure to consult customer service. Ask about the situation. Note that a pair of polarized sunglasses are not suitable for use at night, and the light transmittance must reach the national safety standards.



It is more reasonable to use a visor

According to experts, if using the sun visor above the seat can solve the problem of dazzling sunlight, it is generally not recommended to use sunglasses. Although high-quality sunglasses can effectively reduce the impact of light on human eyes, they will more or less affect vision. Driving as a high-risk behavior, misjudgment of the environment can easily lead to accidents. If you really want to use sunglasses while driving, it is recommended that you develop a habit of wearing sunglasses to walk or work during your daily. Also, you can choose dedicated driving sunglasses. What needs to be reminded is that if your sunglasses are not usually worn, don't use them alone in the car.


What are NXT Lenses?

NXT lenses are made of Trivex materials. Trivex (Chinese name: Ethyl Carbamate Polymer) was invented by PPG in 2001.

Impact resistance:

Impact resistance is the main feature of the NXT lens. As a visual armor material originally used in the military field, Trivex has effective impact protection to the eye when it is most demanded. It is 10 times stronger than PC lenses in impact resistance and will last for life under normal use. It is the only explosion-proof safety lens on the market that can withstand external forces and turns.

Patented color injection technology :

Color representation is another important feature of NXT lenses. The biggest defect of the regular lens in dyeing is color aberration. The same color of the lens with different luminosity will produce different effects. The higher the refractive index, the serious the error. NXT lenses are a breakthrough in this respect. The patented color injection technology that infuses the color into the raw material gives the lens a natural color, ensuring that color aberrations are minimized and that they do not fade or change color over time or over long periods of use like other materials.

Abbe number and internal stress:

The Abbe number of NXT lenses made of Trivex is 43~45, which is close to CR39(58) and higher than PC lenses (29~32) and high folding lenses (32~41). At the same time, because the NXT lens is produced by the casting process, there is no stress in the finished lens, which further reduces the rainbow phenomenon, providing a guarantee for the clear visual effect and reducing eye fatigue.

Weight:

The specific gravity of NXT lens is 1.11g/cm3, 16% lighter than CR39 (1.32g/cm3) and 10% lighter than PC tablet (1.22g/cm3). The Trivex 1.53NXT medium-fold lens is so light that it can float.


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Advantages Of Acetate Frames

  • Firmness and good gloss. The style is beautiful. It is not easy to be deformed and discolored, and it is durable.
  • It is not easy to be corroded by the sweat of the skin and other irritants, and it will not be discolored by ultraviolet radiation.
  • Diverse styles, various colors, suitable for many types of people, and easy to match clothes.

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