How to clean the lenses?
When wiping lenses (especially the rimless glasses of resin lens), you must use a special wipe lens or soft handkerchief or paper. When you wipe the lens, you can only wipe it in one direction, not in circles, and don't touch the lens with your fingers. When the lens is stained with dust and sand, it should be washed with water before wiping, otherwise, the lens is likely to be abraded, and the operation should be gentle. At ordinary times, when cleaning, do not exert too much force, pay attention to the grasp of strength. When wiping the lens, it is best to take the side frame with one hand, and the other hand takes the glasses cloth to wipe gently. In order to prevent the lens film layer falls off, do not use alkaline detergent to wipe the lens. Therefore, when bathing or playing at the seaside, glasses should be properly kept to avoid water vapor or seawater caused by corrosion of glasses.
At present, there are two prescriptions for reading glasses. One is to adjust the power of glasses with clear objects at close range, plus 1/3 of the power for adjustment. The other is to use low power that can see close objects clearly. The practice of many elderly people has proved that the latter one is better between two methods.
The classification is different.
Acetate frames can be divided into two kinds, one of which is the lens using acetate fiber processing of plate cutting. The other is the injection frame. It uses acetate fiber particles. Acrylic acid is a kind of unsaturated organic acid, which can be derived from a series of compounds to form a large class of acrylic products. Acrylic acid downstream products contain common acrylate and special acrylate. It has the characteristics of heat resistance, weather resistance, aging resistance, strong adhesion, water resistance, acid and alkali resistance, stickiness resistance, and environmental friendliness.
Why should the surface of the lens be hardened?
Compared with glass lens, resin lens has the characteristics of lightness, safety, and comfort, but resin lens friction with dust or gravel in the process of use, resulting in lens wear and forming scratches. These scratches in the center of the lens can interfere with vision.
Therefore, in order to improve the wear resistance of resin lenses, it is necessary to add a layer of anti-wear film to the surface of the lenses. This is the hard coating technology of the lenses, which is called Hard coating.
What is the best lens material?
The world's first resin lens was made of CR-39 material, and CR-39 is still the main optical lens material in Europe and the United States. After the end of World War II, people found that compared with glass, the main lens material at that time, the light transmittance of CR-39 is high, and it can block ultraviolet light. In addition, CR-39 can be dyed, not easy to fog, and has small dispersion (CR-39's Abbe number is 58) and other benefits.
How to Choose Glasses for Big Heads?
In this section, we will show you how to choose an eyeglasses frame for large heads. If you do not know how to choose, keep on your reading to find some solutions.
Rectangular frames: Rectangular frames add angle and can slim down the appearance of a larger head. So, if you have a big head, try the rectangular frames glasses.
Oversized frames: if you have a big head, the oversized frames would be a good choice. Oversized glasses will balance out your larger features.
Wayfarer frames: whether your style is retro or geek chic, you will find a perfect fit in trapezoidal wayfarer. The thick angular frames offset rounder cheeks and draw attention down from the forehead. So, if you have a large head, try this style.
When choosing glasses for large heads, you should also find the right shape and color for your signature look and style. While there are a lot of glasses styles for big heads, you should consider glasses with long enough temple length, the length between the hinge of your frames and where they bend around the ear. This measurement is critical for overall comfort, especially on your temples and near your ears.
So, from the above information, you have learned how to choose glasses for big heads.
The frame of prescription glasses
At present, the more common materials for frames are non-metal and metal. Non-metals mainly include TR90, sheet material, etc., and metals include alloys, titanium, and so on. TR90 and sheet material are actually plastics, but they are firm and are not easy be deformed at room temperature. Also, they have good formability so that they can be made in many fashionable styles. The general alloy material has good firmness and flexibility, but the disadvantage is that it is easy to fade. The pure titanium frame is corrosion-resistant and very strong. It is about 40% lighter than the general alloy frame. It must be welded and electroplated in an oxygen-free state, which requires high equipment and technology. Relatively speaking, the price of TR90 and alloys will be lower, and pure titanium will be more expensive. You can choose according to your budget.