What Is Polycarbonate Lens?
Polycarbonate was developed in the 1970s for aerospace applications and is currently used for the helmet visors of astronauts and for space shuttle windscreens. Polycarbonate lenses were introduced in the early 1980s in response to a demand for lightweight, impact-resistance lenses. Since then, polycarbonate has become standard for safety glasses, sports goggles, and children’s eyewear.
Polycarbonate glasses are thinner and lighter than regular plastic lenses. They provide 100% UV protection and are up to 10 times more impact-resistance than plastic or glasses lenses. Polycarbonate glasses also offer clearer and more comfortable vision if an anti-reflective coating is applied to the lenses, which can eliminate distracting lens reflections that interfere with vision, particularly when driving at night or in other low-light conditions when glare sources are present.
However, polycarbonate lens is a naturally soft material, making it more subject to scratching without adequate protection with a scratching-resistant coating. Polycarbonate glasses have high dispersion due to its low Abbe value of 30, causing chromatic aberrations.
How to Choose Glasses for Square Face?
What glasses suit my face or what glasses suit my square face? If you have the same questions, you come to the right place. This post will show you some advice.
In fact, there is a wide range of eyeglasses available for square faces. Round and oval glasses are the best choice for people with square faces. These frames will soften and balance your strong jawline and add contrast to your face shape.
Now, we will show you some suggestions for the glasses for square faces.
Round glasses: round glasses are a sophisticated, polished look that works well with a square face shape. No matter what color you choose, this style works beautifully with a square face shape.
Browline glasses: as for glasses for square face, you can choose the browline glasses. These glasses are thicker at the top, mimicking the way the eyebrows frame the face. Their unique design is one of the best glasses for square faces.
Vintage, Large Round Glasses
Round frames will be popular in 2021, but not only that, square and rectangular face shapes will work well. They can be mixed and matched with everything from business clothes to stylish sweaters and hats. If you're looking for a bolder look, oversized round frames are perfect for you. Smaller frames are more elegant, but you can opt for stylish colors.
How to Keep Glasses from Slipping
As for how to prevent glasses to slide down your nose, you can wear your glasses with a combination of material flexibility and friction. At the same time, you can also try some hacks or use some accessories to keep your glasses from slipping down your nose.
Eyewear Bands
To stop glasses from slipping down nose, you can use eyewear bands. These bands will prevent your glasses from marking them safe on your nose. The eyewear bands are great for stylish eyeglasses, reading glasses and wooden sunglasses. The length of the bands is adjustable to fit your head and neck.
Frame Tightening
To prevent glasses from sliding down your nose, you can choose to tighten your frame. You can ask the optician at the local optical store for help. However, after a while, the glasses will become loose and start to slide down again. So, you need to try tightening the frame again.
Eye Shadow Primer
As for how to keep glasses from slipping, you can use the eye shadow primer. You may feel strange when hearing the eye shadow primer trick. It is a popular one. Using the eye shadow primer on the bridge of your nose, especially where the nose pads come in touch, will prevent any slips. But this way also comes with some inconvenience because it requires you to do that every day.
Glasses Chains
To stop glasses from slipping down nose, you can use some glasses accessories, such as glasses cords and chains. With them, not only do they help your eyewear stay still, but you won’t have the risk of them. The glasses chain helps you to put hen on and off whenever you need them and stop your nose from slipping from your nose.
What is the bifocal lens?
Bifocal reading glasses are characterized by distance vision correction in the upper part of the lens and near vision correction at the bottom. If you need help with both, that's great. This lens is designed to facilitate the working of reading glasses and standard prescription glasses, all in one frame. Glasses are recommended when you are diagnosed with presbyopia, and bifocals are usually the first choice. But for intermediate vision, bifocals are difficult because they're not close enough for the reading part of the lens, and they're not far enough away for the distance part of the lens. Bifocal sunglasses have no magnification at the top, and the reading ability is at the bottom of the lens. Bifocal reading glasses can be found anywhere reading glasses are sold, but they can be harder to find than full magnifying lenses.
Orthokeratology lens
Orthokeratology lenses appeared in the United States in the 1960s and became mature in the 1980s. In 1996, Taiwan first imported the product, and it entered mainland China the following year. It is called OK lens for short because of its pronunciation. After OK lens entered China, it was immediately found by businessmen. A lot of institutions and individuals who do not have the relevant qualifications have flooded into the operation of the OK lens. On July 5, 2001, the State Food and Drug Administration formulated the Regulations on the Supervision and Administration of the Operation, Inspection and Matching of Orthokeratology Lens, which regulated the operating institutions and testing and matching institutions of Orthokeratology lenses. But in China, the rule did not change the course of events.
What are the advantages and disadvantages of bifocal reading glasses?
The advantage of bifocal reading glasses is a large field of vision, and they can be used with the same pair of glasses to see far, near. The cost is lower. But different areas have obvious intervals, and the appearance is not beautiful. The middle distance is fuzzy. They need to adapt to the period. Bifocal reading glasses lens is divided into two parts, and the degree of the two parts is not the same. The upper part is the mother of the flat area to see far, and the next part is the child of the reading area to see near. There is an obvious interval. The appearance is not beautiful. There is no transition area between two different areas, so its vision is fuzzy, easy to produce a 'jump image'. Long-term wearing will make people dizzy or fall down when climbing stairs.
