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 Varifocal Glasses?
Varifocal glasses, also known as varifocals, varifocal lenses, PALs, or progressive lenses, have a gradual change in strength from the top of the lens to the bottom with multiple focal points in between. This allows you to see all distances and focus points through just one lens. Varifocal lenses are typically used when you have two prescriptions, one for distance and one for reading.
There are three regions of a varifocal lens which are distant zone, intermediate zone and, near/reading zone. Usually, the upper portion of the varifocal lens is the distant zone and the bottom portion of the varifocal lens is the near or reading zone.
One of the benefits of varifocal glasses is that you do not need to prepare 2 separate pairs of glasses or need to switch between frames for different vision needs.
Characteristics of titanium frames
Titanium is widely used in the eyewear industry because it is not easy to deform, fade and has strong stability. The glasses frame made of titanium can highlight the noble taste and elegant temperament. The glasses frame made of titanium can be divided into pure titanium, titanium alloy, and beta-titanium frame three kinds. To learn about titanium frames, how to identify pure titanium frames?
Titanium frame has the benefits of low density, high strength, good mechanical properties, and strong corrosion resistance. The frame is very light and not easily corroded by moisture. However, due to the poor process performance of titanium alloy, machining is very difficult, the glasses frame made of hydrogen, oxygen, nitrogen, carbon, and other chemical impurities are more absorbed. The wear resistance of titanium alloy is relatively poor, and the production process is relatively complex, so the cost is relatively high and the workmanship is relatively complicated when using this material to make the spectacle frame. The price is much more expensive than the common spectacle frame.
Identify the lenses of discount glasses
Look at the overall package: let him show you the overall package of the lens. See that if the factory is in China, Shanghai, China, or Zhejiang, China, etc. Look at the anti-counterfeiting logo. It doesn't necessarily mean it's good. Check the production plant, address, news, etc. In short, lens judgment, for the average consumer, is difficult, but when you put forward these requirements, the store will at least think you are more professional.
Single Vision Lens
Single vision is the most commonly used prescription lens. This lens type has a single field of view or a prescription ability of the entire lens and can be used to correct myopia (nearsightedness) or hyperopia (supervision). Some people need glasses to keep their distance and read. Instead of having a pair of single-vision glasses for each pair of glasses, bifocal or progressive glasses may be a more convenient choice. Unlike single vision, bifocal and progressive lenses are multifocal lenses with multiple focal points, such as distance and near distance. People whose prescription for spectacles list the numbers in the 'ADD' section require bifocals, progressive glasses, or reading glasses because your glasses need to add ADDitional to the distance prescription to see close distances.
Advantages of aspheric lenses
In reality, aspheric lenses were originally born to improve the marginalized optical properties of spherical lenses. The aspheric lens with special coating treatment has perfect visual performance, with a clearer, more comfortable visual effect. You can hardly feel the presence of aspheric lenses when you put them on. So you can enjoy the ease brought by aspheric lenses. They are more natural and more realistic, having less visual distortion. The aspheric lens can be designed with a flatter base arc, which not only makes the appearance beautiful but reduces the peripheral magnification so that when others look at the eyes of the people who wear glasses, the size will not change much.
How To Use Contact Lens Correctly?
Check your eyes for abnormal cases. Do your eyes sting or dry? If so, it is recommended not to wear contact lenses for the time being. Look in the mirror to see both eyes carefully, if it is red and swollen or if is both eyes full of bloodshot? If you do, you can no longer wear contact lenses, and you can go to a professional store for inspection. After putting on the contact lenses, block the left and right eyes respectively to see if the vision of one eye is clear. If the eye vision has decreased or blurred, check if the lens is dirty. If the lens is still the same, you should go to a professional store to find out the reason.