Titanium is currently too expensive to refine.
It is highly demanding in buckling, stamping, cutting, and welding. The extraction of titanium, like that of aluminum before the 19th century, was quite costly and produced in limited quantities, so it was used only in extremely important fields, such as aerospace, electronics, precision instrument manufacturing, and so on.
Alloy glasses frame
Spectacle frames made of the alloy have relatively high hardness, are more resistant to friction, are not easy to fade, have a better texture, and are made of more styles, which are essential for fashionistas.
Thickness of lens
The thickness of the driver's glasses affects the use of glasses in a way. The glasses with thicker lenses can be more durable to prevent the glasses from being irritated and accidentally broken, effectively protecting the eyes.
Adjustment of the angle of the nose pad
For the angle of the nose pad, you can apply torque in the horizontal or vertical direction according to the deformation needs. It can be held in the proper part of the nose pad with needle-nose pliers, and the torque can be applied at a certain angle in the vertical plane or horizontal plane to achieve the purpose in accordance with the deformation needs. In the time of repeated actions, in order to prevent the welding place of the nose pad and the glasses ring from breaking due to repeated stress deformation, you can use your fingers to apply external force at the welding place to change the deformation position and play the purpose of protection.
Basic principles of progressive lenses
The surface of the progressive slice is divided into five regions. There are far, middle, and near optical areas. They are respectively corresponding to see distant objects, middle distance objects in the near distance objects. One pair of glasses is multi-purpose. In appearance, it is not very different from regular lenses. There is no clear dividing line. Distal use area: The area above the progressive slice is the distal use area, which is used to correct the distal refractive error. Proximity area: from the matching lens cross down, the refractive power of the lens continuously increases the positive degree, which is used to see close objects. Gradient area: The channel connecting the far and near areas. It is an area of regular change from top to bottom, used for transitioning and seeing objects at intermediate distances. The length of the gradient is very important for the wearer's adaptation. The rate at which the degree of gradient changes is called gradient. The gradient can be uniform or variable. Peripheral area: Changes in the surface curvature of the lens will lead to aberrations in the peripheral areas on both sides of the lens, mainly astigmatism and prism effect, which will interfere with a vision to a certain extent, resulting in blurred vision or distortion. And it will affect the wearer's adaptation to the progressive lens.
5 Signs You Need Reading Glasses
In this section, we will list some signs you need reading glasses.
- You are over 40 years old. Everyone’s eyesight changes at a different rate, but most people develop presbyopia in their 40s. Presbyopia is a condition in which the eye strain to focus on nearby objects, which is different from farsightedness, a condition in which you can see distant objects clearly, but objects nearby may be blurry. Farsightedness is usually present at birth, but presbyopia develops during the aging process.
- If you find that you never seem to have enough light when reading, regardless of the room type or the number of lamps you have turned on, it may be time to get reading glasses. According to a study, a 60-year-old people requires three times as much light as a 20-year old to do the same task.
- If your eyes get tired when reading or working at your computer, you may need reading glasses. Do you find yourself dozing off at your computer, or do your eyelids get heavy when your reading or do detailed work? If so, you may be developing presbyopia, and you may need the reading glasses.
- Another sign you need reading glasses is that you are getting more headaches. Consistently straining your eyes to read or focus on craft could give more headaches. A headache right behind your eyes could be indicative of hyperopia. It is important to remember the 20-20-20 rule: every 20 minutes, look at something at least 20 feet away for 20 seconds. If your headaches persist, you should see an eye doctor and have a check.
- If you see halos, you may need reading glasses. When your lens cannot focus light into your retina, it makes your vision appear blurry. Thus, reading glasses can solve this problem.
Do I need reading glasses? After reading this post, you may have a basic understanding. If you need a pair of reading glasses, try Koalaeye glasses. They are stylish and cheap, and the glasses will be mailed to you with great convenience.
Why do you need to adjust your glasses?
After wearing glasses for a period of time, the frames will become deformed and loose. Due to the deformation of the frame, the wearer may experience blurred vision, dizziness, visual fatigue, and other symptoms, the glasses need to be adjusted regularly. And because the shape of each person's face and the relative position of nose and ears are different, you need to adjust your glasses according to your own features. To make wearing comfortable, glasses do not overpress the nose and ears. After wearing glasses, it is advisable to have no tenderness at the contact point and not to slide down the head frame. The frames have to be made fundamental adjustments after assembly to meet fundamental standards.