In terms of positioning, it should conform to students' purchasing behavior, that is, the middle and low-grade products are mainly used, and the appearance requirements are stylish and novel. In addition, you can be properly supplemented with a small number of high-end products, because your market is not only the school but many residents around.
The advantages are not the same.
The cellulose acetate frame is acetate plastic, belonging to a kind of thermoplastic material, and it is a material for nearly 20 years. It is widely used in the glasses industry material. Now with the progress of processing technology, it can be divided into plate and injection molding. The acrylic frame of the propionic acid fiber belongs to a kind of thermoplastic material. The appearance is transparent. The main feature is that the material density is high. They are hard to burn and are not easy to change color, with Impact resistance. It has softness, dimensional stability, and good processing formability. Many high-grade plate glasses are based on these high-quality plates, so the quality is more reliable. It is designed for a large number of people and the pursuit of quality of life students, especially for women.
What are the characteristics of a titanium frame?
The so-called pure titanium, titanium refers to the purity of more than 99% of the titanium metal materials. To tell if a pair of glasses frame is pure titanium, we look at its purity. Because of the high melting point of titanium, lightweight, strong corrosion-resistance, used for the frame, they can wear for a long time, and will not let the bridge of the nose have a sense of pressure. But its disadvantage is that the material is soft, and only the relatively rough frame lines are made to ensure the stability and strength of the frame. Titanium frame has the advantages of corrosion resistance, acid and alkali resistance, high stability, good elasticity, good toughness, not easy to deform and fade. General glasses frame contains copper, so when we wear for a long time .it will produce verdigris, namely, copper sulfate. It is a toxic substance and is harmful to the human body. Because pure titanium tends to be soft, copper has to be added to make the frames more stable, which is why the frames have to be replaced over time.
Disadvantages of Progressive Lens
There are deformation areas under the left and right sides of the lens, which make the image blurry and irregular. It takes 1-3 weeks to get used to it. In addition, it has a narrower field of view in the near and middle distances, and long-term concentration on the narrow focal point can easily make the eyes tired. Suitable for people who need to alternate between distant, medium, and near vision.
However, with the development of science and technology, more and more progressive multifocal glasses have emerged that have a wider field of view, more comfortable wearing, and better meet the needs of eyes. Nowadays, the use rate of progressive lenses among middle-aged and elderly people abroad is quite high. Single-lens and double-lens reading glasses are gradually being replaced by progressive multifocal glasses.
What Are Progressive Lenses?
Your eyes change with your age. When your reach your 40s, you may find that it is difficult for you to focus between a book, a website on a computer screen and the conference room whiteboard. Progressive lenses are growing in popularity among people who need help seeing near, far and in-between.
Progressive lenses have grown in popularity and are one of the most common solutions to treat vision loss that occurs with age or presbyopia. Progressive lenses have a seamless increase in magnification from the top to the bottom of the lens, helping you see clearly at all distances with just one pair of glasses. The top portion of the lens enables you to see the far-away objects, the middle portion of the lens enables you to focus on the intermediate objects and the bottom to see objects close-up. The prescription changes little by little across the lens surface providing a gentle transition.
After knowing what the progressive lenses are, do you know what are the pros and cons of progressive lenses? If not, keep on your reading and we will show you some information.
How to choose blue light blocking glasses?
Look at lens color. Ordinary lens and blue light blocking lens is the same yellow-green film, and they can be placed in light to identify the place.
Regular lenses have a yellowish tinge in the reflection of light. And anti-blue light glasses film color, there is the blue color in the yellow and green film, this is because of the reflection of blue light.
Look at the instructions. Check the specs and test reports of glasses. Look at the lens manufacturer's qualifications and whether the lens contains radiation.
3 Common Problems with Progressive Lenses
Though progressive lenses are popular to correct some eye conditions, there are also some drawbacks. So, in the following section, we will show you some common problems with progressive lenses.
Dizziness: the three different focal lengths of progressive lenses can make people susceptible to dizziness, as well as vertigo. From long to medium to short distance, the lenses offer a gradient of increasing strength. So, it would have trouble in adapting the glasses for the people who are wearing them for the first time. A common mistake is to look out of the wrong focal length, causing their vision to be blurry and lead to an overall feeling of dizziness.
Peripheral distortion: another common problem of progressive lenses is the way in which they blur peripheral vision. Most glasses cause an initial distortion to vision. However, the three different segments found in these lenses can make that distortion feel more prominent than other pairs of eyeglasses. And most people may need two weeks to adjust to progressive lenses.
Depth perception: Since progressive lenses provide three different prescriptions to see objects clearly for different distances, it is important that you need to move your head instead of your eyes when focusing on objects at different distances. Prior to adjusting to this little nuance, progressive lenses can cause depth perception to feel off.
From the above information, you have known some common problems with progressive lenses. So, you may ask how to adjust the progressive lenses. The most popular way is that you need to wear them frequently.