How to Know If You Need Bifocal Glasses?
As you get older, you will find that is more and more difficult to read or focus on things that are really close up. This is called presbyopia and it is a common eye condition among older people.
How to know if you need bifocal glasses? If you find yourself squinting at the text that once was easy to read or your vision is blurry, you may need to see an eye doctor. In this situation, you may need bifocal glasses to correct your eyes.
If you currently wear glasses but see print more clearly when you remove them, it is a sign that you may need bifocal glasses in the future.
To know if you need bifocal glasses exactly, check your eyes by an optometrist or ophthalmologist.
The history of chromatic contact lenses
Chromatic contact lenses, commonly known as color Lens, is a kind of Soft hydrophilic Contact Lens, belongs to the third category of medical devices. In 1971, Bausch & Lomb introduced the world's first pair of soft contact lenses. Before this, contact lenses are made of hard materials, with poor comfort, difficult to promote. Soon after, CIBA Vision made the lenses aqua blue to make them easier for users to operate. There were also special contact lenses with dark loops on the lenses, which were designed to help people with injured or defective eyes, like corneal white spots or iris defects, to conceal flaws, forming artificial pupils, so they were called beauty lenses.
Then, in the 1980s, American company Wesley Jessen (later bought by VisiCon) introduced the FreshLook chromatic contact lens, which used laser technology to print colored patterns onto the lens to change the color of the wearer's iris. Since then, contact lenses have been developed from a simple vision correction tool into a cosmetic with the effect of beauty makeup. It can brighten, enlarge, darken or change the color of the iris of the eye. At present, the common chromatic contact lenses are black, brown, gray, purple, blue, green, and so on. There are also a variety of color combinations or some special patterns.
Are beta titanium glasses frames expensive?
What’s the probable price of a Beta titanium eyeglass frame? The price of β titanium frame and pure titanium are similar, and the price is usually high, But hundreds to thousands, according to the brand and workmanship. Beta-titanium is usually cheaper than pure titanium. Why are titanium and beta-titanium cheap, but expensive to process into eyeglass frames? The so-called pure titanium and β titanium frames are really titanium alloy frames in the strict sense, and the processing difficulty is really great. IP plating must be used for electroplating, so the processing cost is much higher than that of copper alloy, and the labor cost needs to be included.
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.
The main parts of glasses
1. Spectacle lenses
One of the most important accessories for glasses is spectacle lenses. Due to the increase in myopia patients, the demand for spectacle lenses is also very large, but the prices of spectacles on the market are also uneven. To know whether the spectacle lens is good or not, you can't just look at the price of the product, but learn more about the value of the lens itself. For example, the resin lens is lighter and suitable for patients who wear it for a long time. The quality of the optical glass lens is better, and it is not easy to break, suitable for some elderly people.
The quality of spectacle lenses is also a key consideration. The market generally classifies lenses based on their structure, materials, and usefulness. The information on spectacle lenses is mostly chemical substances. It is very beneficial for us to select some good-quality lens materials. It is not only necessary to consider the function of the lens, but also to consider whether the lens material is harmful to the human body. Generally, the crystal stone materials are very safe and reliable, and we can choose carefully.
2. Spectacle frame
Another important figure in eyeglasses accessories is the frame. For those who like lightweight glasses, it is more appropriate to choose ultra-light frames or half frames. However, the frame must have durable and play a good role in maintaining the lens, otherwise, it will lose the meaning of the frame. Of course, the temples are also a part of the frame. There are also nose pads for glasses accessories. Many people have more requirements for nose pads. Generally, they choose soft ones that are not easy to press on the bridge of the nose.
How to test a blue-light lens?
Look at the lens. High-quality anti-blue glasses do not interfere with the line of sight, with high transmittance. The light transmittance is very high, and the visual clarity is higher, which does not affect the visual quality, quality of life, contrast sensitivity, and color discrimination.
Acetate frame and plastic frame
What is the difference between acetate frame and a plastic frame? Acetate frames are lighter and generally considered to be better than plastic frames. Acetate is known for its hypoallergenicity, so it is a popular choice for people with sensitive skin. Unlike some plastic or metal frames, they can cause allergic reactions.
- The manufacturing process makes the plastic frame more brittle than the acetate frame.
- If the temple does not have a metal bracket, it is difficult to adjust the plastic glasses.
- There are fewer choices of colors and patterns for plastic frame
However, you will notice that acetate frames are generally more expensive than ordinary plastic frames. Spectacle frames are daily necessities that we use for a long time. Therefore, durability is essential, and the life span of the acetate frame is longer.
