How do bifocal reading glasses work?
Bifocal reading glasses have two different lenses on the same lens. The top of the lens is your normal distance prescription, while the bottom is for close-up viewings, like reading. The two lenses allow you to alternate between them by moving your eyes up and down as needed. A bifocal lens is a type of lens that has two different areas of vision: one for close range and one for long-range. Typically, the upper section covers remote vision and the lower section covers reading. With a traditional bifocal lens, you can see the difference between the two lenses because the lower curve is a little different.
Progressive lenses and single vision lenses
An optical lens that has only one luminosity on a single vision lens and does not have special functions.
The curvature of the front surface of the progressive lens increases continuously from top to bottom, and the refractive power increases gradually and continuously from the distance zone located on the upper part of the lens until the near zone at the bottom of the lens reaches the required near-use refractive power. A pair of glasses can be used. You can see far away, you can see close, and you can see objects in the middle distance.
Clean Glasses Properly
If the glasses are dirty, don't just wipe them with other cloth. If you use some hard cloth to wipe, it is easy to cause scratches in the lens. Generally speaking, the following cleaning methods are all feasible.
1. Use neutral or alkaline cleaning agent. Remember, toothpaste cannot be used as a substitute for the cleaning agent for spectacle lenses. General optical shops also sell lens cleaners in small bottles, which are easy to carry.
2. Go to the optical shop for professional ultrasonic cleaning. General optical shops provide free cleaning services. The ultrasonic cleaning machine can fully clean every gap and groove of the glasses.
3. Rinse the lens with tap water. Hold the frame in one hand and the cleaner in the other hand. Rub it slowly against the lens, and then rinse it off with clean water. Then wipe it with a glasses cloth or let it dry naturally.
In addition to the glasses cannot be cleaned with alcohol, you should also pay attention to their placement for daily maintenance. Try to avoid putting it under high temperature, and avoid oily, smoke, etc. If you don't use them, put them in the glasses case.
Glasses for heart-shaped faces
This type of face has a wide forehead, broad cheekbones, and a pointed chin. It is called a heart-shaped face. The upper part of the heart-shaped face is relatively wide and flat, and the lower part of the line is uniform and smooth. The facial line, the proportion is very soft, giving a person an intimate intuitive feeling. Wearing longer or rimless glasses for this face shape will make you look cute.
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.
When should I use blue light glasses?
Most of us spend a few hours a day in front of a screen. Because so many people work on a computer all day, many people wear blue glasses in the office. At the same time, many American high school and college students spend hours a day on their computers and could benefit from blue light glasses.
Select qualified optical lenses.
Anti-blue light lens must be qualified optical lens first and must have a certain percentage of anti-blue light effect. The general anti-blue light optical lens effect is about 30%. Even if it is not nearsighted people, it is best to choose the brand lens of reliable optical lens production enterprises. Anti-blue light lens is only suitable for people who use electronic display devices such as computers for a long time and is not suitable for patients with visual fatigue symptoms.