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.
Seek professional help.
Many plates, TR glasses have fixed nose pads that cannot be changed. But the metal material of the nose pad can be changed. An optometrist who is a professional optometrist may not be a good adjuster. There is no conflict between the two. The skills about that shall be developed in a lot of practice. For a seemingly easy operation, its strength is invisible real skills.
Overnight Glasses
Overnight Glasses is created by experienced members of the optical industry. You'll get high-priced lenses, coatings, and prescription glasses approved by the FOOD and Drug Administration (FDA) and the American National Standards Institute (ANSI).
Production, inspection, and customer support are all done by certified opticians in the US with 100% accuracy. Freeform Progressives Lenses designed by Seiko, Transitions Lenses, Trivex Trilogy, Nu Polar Polarized films, even the most basic prescriptions for monopod lenses, are manufactured, assembled, and double-checked in the United States by their certified personnel. The inventory includes prescription glasses and prescription sunglasses from well-known brands such as Ray-Ban, Oakley, Dior, Versace, Salvatore Ferragamo, Dolce and Gabbana (D&G), Prada, Tom-Ford，Burberry Eyewear, and Ermenegildo Zegna are both priced at less than half what other retailers offer.
Consider possible uncertainties after the lens is installed.
Usually, in-store frames are made of plastic samples rather than actual lenses, so they weigh slightly less. However, it is necessary to consider the approximate weight of the lens in advance according to its own degree when trying it on, in case the weight is not suitable for real wearing. If the pupil distance is too small, it is not suitable to wear a wider frame. The machinist should strictly follow the left and right pupil distance instead of taking the average, otherwise, there will be pupil distance error in the left and right eyes, which will cause discomfort in wearing.
Advantages of Progressive Lens
Continuous and clear vision throughout the entire process is the advantage of progressive lenses. Because the added value continuously increases gradually in the gradient zone, the wearer can obtain continuous clear vision from the far point to the near point through the gradient lens under the appropriate head position. In line with physiological optics, better adaptation. The appearance is better than that of double-lens and triple-lens. There is no dividing line of sub-sheets, and there is no ring-shaped blind zone and invisible sub-sheets.
Identify the frames of discount glasses
Electroplating spraying refers to metal frames, all need to be plated on color. Spraying, the quality of this process, determines the quality of the frame. Glasses are not high-tech, but details like hinges -- the joints that open and close -- make a big difference between good and bad. The little screws inside, about four of them (hinges and nose pad), are important.Silk screen printing or laser engraving refers to the above logo or data, some of the silk screen, easy to sweat and fade, does not affect the use. Some laser engraving, basic will not fade, so, look at these details, can probably judge the stand or fall of the frame.
Titanium frame machining is complicated.
The elastic modulus of titanium alloy is small, which is easy to produce large deformation, springback, distortion, and vibration in cutting, resulting in poor geometric shape and accuracy of the workpiece. As the surface roughness increases, the tool wear increases. The thermal conductivity of titanium alloy is poor and its thermal conductivity is small, 1/6 of that of 45 steel, so the high heat generated in processing cannot be effectively diffused. It is even harder to use titanium to make glasses. The frames are very thin and a lot of fine work is demanded. It's definitely a challenge for titanium, which is pretty difficult to work with. In addition, titanium alloy frames involve titanium alloy welding technology, which is more difficult.
