Why are eyeglass frames are so expensive?
Plastic frames are often used for rimless glasses, but they are not very resistant to corrosion and break easily. The plate is a new type of plastic, and it is light and has high hardness, not easy to deform, but the surface is easily corroded by sweat. TR90 has features of wear resistance, good chemical resistance, solvent resistance, weather resistance, not burning, high-temperature resistance. Plastic steel does not contain any metal, but it is a kind of high-strength molecular material, lighter than TR90. They have a higher level in corrosion resistance and strength and other aspects. The frames made of good materials are more comfortable, durable, and textured in daily wear, and will not cause skin allergies. Plate, titanium, TR90, alloy are the most used materials on the market at present. The price is in dozens of yuan to hundreds, thousands of yuan.
Does it matter if the frames are broken?
If the frame is broken, there may be inconsistencies between the left and right temples. This will cause the lens optical center shift, long-term wearing will make teenagers feel dizzy and vomiting. Many people will be attributed to the high degrees of this situation. The position of the nose pads is not consistent: this kind of lens deviation from the left to the right causes the prism effect, which makes the wearer can not see clearly, blurred. When the temple is too loose or too tight, it will affect the comfort of wearing the glasses, and the excessive pressure on the temple will cause pain in the head.
Design principle of progressive multifocal lens
For the same piece of the lens, the top is used to see far, the bottom is used to see close. The upper and lower degrees are different.
There is not a sudden change in the distance degree fixed above the lens to the near degree fixed below the lens, but a gradual transition between the two through gradual changes in refractive power, which has special benefits over common bifocals or trifocal lenses.
Why are rimless glasses so expensive?
Although the overall volume of materials selected for rimless glasses is a little less, the special structure of rimless glasses requires much higher physical properties (flexibility, surface texture, etc.) and processing accuracy than TR, PEI, and other materials. Rimless glasses require higher quality lenses. For example, lens materials with a refractive index of 1.56 tend to be brittle for rimless glasses and should be chosen with caution. Generally speaking, the time of processing about three pairs of half-frame glasses is equal to the time of processing of a pair of rimless glasses.
What is blue light?
Blue light is an important part of natural light, and it is visible light with a wavelength of 400nm-500nm in the spectrum. Blue light can be divided into short-wave blue light (harmful blue light) and long-wave blue light (beneficial blue light). Short-wave blue light harms people’s vision and causes specific diseases, while long-wave blue light helps people maintain normal physiological functions, regulate biological rhythms, and treat specific diseases.
Blue light can be seen everywhere in daily life. In addition to blue light in the sun, electronic products such as TVs, computers, mobile phones, ipads, and LED lights also produce blue light in our daily.
A Suitable Nose Pad
The Nose pad must fit the nose to the maximum extent possible. If they do not fit, the opticians have special pointed tools. It's best not to adjust the nose pad yourself. A lot of store staff are afraid to adjust the nose pad, just because it is difficult. The general store processing master will adjust the nose pad. The nose pad can be adjusted on the premise of the same rake angle.
What material is the lens coating used?
The anti-reflection film material of glass lenses is usually magnesium fluoride. Because the coating process of magnesium fluoride must be carried out at more than 200℃, otherwise it cannot be attached to the surface of the lens. The resin sheet is not used. Since the 1990s, with the development of vacuum coating technology, the combined effect of film and lens has been improved. At the same time, high purity metal oxide materials like titanium oxide and zirconia can be deposited on the surface of the resin sheet through the evaporation process to achieve a good anti-reflection effect.
