How to determine whether progressive lenses are worn correctly?
Once your glasses are back from the lab, the optometrist will let you put them on for an audition and make final adjustments to make sure they fit. If the prescription is not in the center of the lens, it will make it difficult for you to see clearly. The key is that the lenses match the wearer's eyes, especially the pupils. Before ordering a new lens, the optometrist takes two measurements: pupil distance and fitting height.
What Is Progressive Lens?
Progressive lenses, also called multifocal lenses, have three prescriptions in one pair of glasses. So, it allows you to see near, middle distance, and far objects without changing your glasses. The progressive lenses are designed for people who are over 40 years old who are both nearsighted and farsighted. The progressive lenses come with the following features:
- There is no distinct line between all visions(near, intermediate, and far).
- Most popular lens for anyone with presbyopia who wears
- Expanded intermediate zone for better computer vision.
From the above information, you may have known the differences between bifocal lenses and progressive lenses. As for progressive vs bifocal lenses, which one is better? It is difficult to judge because each of them has unique features. So, if you do not know choose which, you can listen to the eye doctor.
The extraction of titanium
Nowadays, the commonly used extraction method is the reduction method of titanium tetrachloride. Compared to copper and zinc, although high in content, much more expensive. On the other hand, China is the country with the largest reserves of titanium, and a large number of steel mills with perennial overcapacity began to produce titanium, so the price of titanium fell year after year.
What are night driving glasses?
Night driving glasses are usually non-prescription glasses with yellow lenses and can be bought in many optical stores or online. Lenses range in color from light yellow to amber, and some night driving glasses have an anti-reflective coating. The yellow night driving glasses have been manufactured and sold for decades. They were originally sold to hunters as shooting glasses because they gave birds a sharper contrast to the sky on overcast or overcast days.
About the early domestic anti-reflection coating lens
Chinese coated lenses appeared in the mid-1980s. At that time, Europe (such as France and Germany) and Asia (such as Japan, Singapore, and Taiwan) had already launched coated lenses to the market, and the grade of lenses was evaluated based on the quality of the anti-reflection effect. Among them, Germany and France were the two leading countries in technology. Technically, the use of French original film material (referred to as H2) can reduce the effect by 99.98% (refers to the light transmittance, the same below). Almost you can not see the reflection, but the material is expensive. Therefore, the coating lens which is currently used in the world is born. The anti-reflection effect is controlled at about 98%, so the coating cost is greatly reduced. And it is accepted by consumers because it presents various colors, especially green. At the same time, because at the same time, it can be easily distinguished from non-coated lenses. It can reflect the high-grade film lens, and it is accepted by the sales staff.
An unlimited discount is not reasonable.
5 discount, 3 discount, 1.5 discount, we can see that glasses category discount is lower and lower. But glasses are not consumable, like cell phones, appliances, or even less frequently than they are. Because, unlike consumables, it has an incompressible cost structure. Behind such discounts, there is sometimes the marketing strategy of raising the price of glasses first and then lowering the price.
Choose clear glasses for kids to keep safe.
Safety is very important no matter in what aspect, glasses are no exception. Especially for children, they are more active. The lens is best made of PC, and the frame is best made of materials with high toughness, such as TR90. Service fixed number of years of this kind of picture frame is long.
