When buying glasses, most people pay attention to the beauty of the style first, but ignore the comfort. In fact, fit means not only to wear beautiful, but also to wear comfortable. Although some people only wear it for decoration, most of them wear it for correction of vision.
When matching glasses, try to wear them. One is the process of running in, and the other is to find problems in time. Unsuitable glasses are not only uncomfortable to wear, but also may increase the degree, so we must pay attention to them.
Don't look at glasses is just two frames + two lenses, but there are still some small ways to choose. This way is divided into five steps: check the light, select the lens, select the frame, look at the style and look at the face shape.
1. Check the light
Optometry is the basis of lens matching, mainly to check the deformation of the eyeball. Generally, there are two methods: one is to use an instrument to check the deformation of the eyeball, commonly known as "computer optometry"; the other is to use a lens to try on and use a pair of interchangeable glasses, also known as "insert optometry". After determining the degree of glasses to be worn, a suitable pair of glasses can be fitted. Large opticians use both methods.
Computer optometry
Computer optometry belongs to objective optometry. Its principle is basically the same as retinoscopy. Infrared light source and automatic fog device are used to relax the adjustment of eyeball. Photoelectric technology and automatic control technology are used to check the diopter.
Insert optometry
However, the results of computer optometry may be inaccurate due to the improper operation and subjective bias of the optometrist, as well as the quality of the machine. So it is very necessary to insert the film for optometry after the computer optometry, and then combine with the individual actual use of eyes and other comprehensive situations, the optometrist gives a prescription for matching glasses.
2. Pick lens
There are four points to choose a lens: material, shape, dispersion coefficient and refractive index.
texture of material
At present, the lenses sold in the market are divided into three types according to the materials: glass, resin and PC. Glass lenses are relatively easy to break, posing a threat to eye safety. Although PC lens has super toughness, is not easy to break and has the lightest weight, it is not resistant to high temperature and is easy to be deformed by high temperature. Because of its advantages of light weight, not easy to break and low price, resin lens is a common choice for myopia glasses wearers.
appearance
Lenses are divided into spherical and aspherical lenses according to different curvature. Spherical lens refers to the lens with spherical surface on both sides, or one side is spherical surface and the other half is plane. The surface shape of aspherical lens is determined by the multi image higher order equation, and the radius of each point on the surface is different. The aspheric design of the lens is a kind of complement to the disadvantage of the spherical design of the lens (aberration). In addition, the curvature of the lens is reduced, the thickness of the lens is reduced, and the glasses of the wearer look closer to the reality.
There is no difference for people with low degree, but for people with medium and high myopia, it is recommended to choose aspheric lens, which has better imaging effect and sharpness.
Dispersion coefficient
Dispersion coefficient is an important index to evaluate the sharpness of lens imaging, which is usually expressed by Abbe number (dispersion coefficient). The larger the Abbe number, the smaller the dispersion and the better the imaging resolution. On the contrary, the smaller the Abbe number is, the larger the dispersion is, and the worse the imaging resolution is.
Refractive index
The concept of refractive index is a little complicated. Let's simply say that the common refractive indexes are 1.56, 1.60, 1.67 and 1.74. Under the same degree, the higher the refractive index is, the thinner the lens will be. When selecting, it is not the thinner the better. You can select by referring to the degree: 1.50 or 1.56 for less than 200 degrees; 1.60 for 200-400 degrees; 1.67 for 400-800 degrees; 1.74 or glass lens is recommended for higher degree.
3. Selection frame
If you buy the wrong frame, no matter how good the lens is, it's a white tie. Because when the mirror frame is bought wrong, the distance between the eyes and the rake angle of the mirror will be wrong, and the two data are wrong. If the wearing time is long, the degree will definitely increase, and even other complications will occur.
Look at the nose rest first
To select a suitable mirror frame for Chinese people, first of all, it depends on the nose bracket. The nose bridge of Chinese people is generally short, so you can buy a large space S-shaped nose bracket, which can refer to the above figure.
If you want to choose a fixed nose rest, it is recommended to purchase a 9 mm or 12 mm high nose rest specially designed for Asians.
Look at the mirror leg again
There are also spectacle legs, which are suitable for Chinese people. Usually, if we see those glasses legs without radian in the glasses shop, it proves that they are foreign trade funds sold to European and American people, and are not suitable for Chinese people.
4. Look at the style
Usually, a pair of glasses is composed of frame, lens, leg, crossbeam and nose pad, but the real element determining the line of glasses is actually the line of frame and crossbeam. According to the line presentation of these two parts, glasses are usually divided into five types. Let's take a look at them together.
Full border
Full frame means that the frame completely covers the lens, and its line type is mainly determined by the frame and the beam.
Half border
Half frame means that the frame only covers a part of the lens. If there is a beam, the line is determined by the beam and the frame of the upper half; if there is no beam, it is mainly determined by the frame of the upper half.
no border
No frame naturally refers to the frame without frame. The line sense of this kind of glasses is much weaker than that of other frames with frame, mainly based on the shape and line of the lens itself.
Bezel
The bezel frame refers to a rectangular plastic frame, which generally has no nose pad, or the nose pad is not obvious. The frame is generally thick and has a strong sense of line.
Eyebrow crossbar frame
Eyebrow side crossbar frame means that there is a crossbeam in the middle of eyebrow, showing the appearance of double beams. The lines of this type of crossbeam also have a great influence on the shape of glasses.
5. Look at face shape
Glasses are not only the necessity of a clear world, but also a sharp tool to modify the shape of the face. The effect of wearing glasses is different for different face types. So when choosing, you can choose according to different face shapes.
round face
Round face gives the impression that people are easy to get close to, and the corresponding disadvantage is that it is easy to show big face. Therefore, when choosing glasses, try to avoid the round or oval shape. It is more suitable to choose the square frame with edges and corners, which can weaken the round lines and make the face more delicate.
Square face
The biggest feature of square face is its clear outline, which can easily make people feel cold and hard to get close to. So at this time, we need some round lines to soften the lines. The round or oval frame is very suitable for this, adding femininity and affinity.
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The long face has a sharp chin that many people admire, and a wide flat forehead, which presents an inverted triangle shape as a whole. The wide frame and dark leg can break the straight line of the long face, shorten the longitudinal length, and make the overall contour more harmonious.
So whether you wear glasses to decorate or correct your eyesight, you should be responsible for your eye health, do every step carefully, comfortable and beautiful, which is the real meaning of choosing glasses. Have you all learned?
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