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.
How did the eyeglasses market develop?
With the discovery of clear glass paste in the 14th century, lenses became cheaper and easier to sell outside Venice. In the 15th century, the invention of the printing press made it easier to read, which greatly increased the demand for glasses. By the 16th century, frames were made of luxurious materials such as horn, leather, and whalebone. They used real turtle shells. The artificial plastic celluloid was later used to make frames that had never been seen before. In the 1950s, glasses became more popular than ever. Even today, glasses are considered one of the best fashion accessories. Different colors and styles of frames can be made according to the face shape. New technologies for lenses, contact lenses, and even frame materials continue to evolve year after year.
About Prism Glasses
The refractive index of the same medium is different for different colors of light. Different colors of light travel at different speeds in the same medium. Because the same medium has a different refractive index for various monochromatic light, and the deflection angle of each monochromatic light is different when passing through a prism. Therefore, white light through a prism will separate the monochromatic light, known as dispersion. What is the prism effect of glasses? As long as there is a deviation between the visual channel of the eye and the optical center of the lens, it can produce a prism effect. Therefore, the severity of the prism effect can be used to measure whether the glasses with the correct prescription are processed correctly and reshaped correctly.
The lenses of prescription glasses
Common materials for lenses include glass, resin, and PC. The glass is fragile and heavy, and few people wear it anymore. PC film is tough and not fragile, but it is not resistant to high temperature and the surface is easily scratched. The most common type of lens on the market today is the resin lens, which is light in weight, hard to break, and reasonable in price. At present, it is generally recommended that you choose resin sheets, and it is recommended that people with ultra-high myopia choose glass sheets.
Generally, lenses can be divided into spherical and aspherical surfaces according to different curvature designs. When choosing, refer to the degree of the eye. For people with lower degrees, There are fewer differences between the two shapes. For people with moderate to high myopia, aspherical lenses will have better imaging effects and clearer vision.
When choosing a lens, a parameter that is often mentioned is the refractive index. Common refractive indexes are 1.56, 1.60, 1.67, and 1.74. With the same degree, the higher the refractive index, the thinner the lens.
Your glasses are not symmetrical.
If one side of the frame looks higher than the other, you need to adjust the arm. If the right side is higher than the left, gently bend the left arm at the hinge or where the arm bends behind the ear. If the left side is higher than the right, gently bend the right arm at the hinge or where the arm bends behind the ear. Adjusting the frames a little at a time may damage your glasses. Place your arms in warm water to make them easier to adjust. Use only warm water from the tap. Don't use boiled water! Because it affects the coating on the lens. If one adjustment is not in place, it can be adjusted several times, and the above methods can be comprehensively used. If the adjustment is really bad, then you have to go to the optical shop to ask the staff to adjust.
Does the phone screen have irregular color bars when wearing polarized lenses?
It is mainly the special properties of the polarizing film. The polarizer is able to see the internal stresses in the plastic, so when we usually look at the edge of the mobile phone screen, it will have a colored stripe or a black piece, which is mainly caused by the uneven edge pressure when the screen is installed. It's mostly a matter of light and shade. Wearing a polarized lens to see the LCD screen a tilt will find that the screen darkens, mainly because the polarizing lens can absorb light in a certain direction. The LCD screen is a one-way light (different from sunlight), so it is absorbed, so it is found to be dark.
What diopters do rimless myopic glasses suit?
What diopters do rimless myopic glasses suit? It suits myopic diopters to be used by people with diopters of 600 or less than. Usually, the high diopters are 500, 600, or above, Rimless glasses can see the lens directly. The higher the diopters, the thicker the lens. Secondly, in rimless glasses, sunlight can shine in from the axis of the lens, resulting in a dispersion effect, which has a certain impact on viewing. Thirdly, rimless lenses, without the protection of the rim, are easy to be scratched and broken, so they need to be carefully protected and stored. So to sum up, people with the diopters of 500 or 600can choose myopia rimless glasses. But it is not recommended to choose rimless glasses for people with diopters of more than 800.
