What Is Polycarbonate Lens?
Polycarbonate was invented in the 1970s for aerospace applications and is currently used for the helmet visors of astronauts and for space shuttle windshields.
Polycarbonate lenses were introduced in the early 1980s in response to a demand for lightweight, impact-resistance lenses. Since then, polycarbonate glasses have become standard for safety glasses, sports goggles, and children’s eyewear.
Polycarbonate glasses come with a lot of features such as thin and light and they provide 100% percent UV protection and are up to 10 times more impact-resistance than plastic pr glasses lenses.
Reduce the amount of time you spend using electronics.
When children are developing their eyes, parents should limit the amount of time they spend with electronic devices. Increase outdoor exercise and combine work and rest. In today's high-pressure and competitive learning environment, children face textbooks, homework, and exams for a long time, and their eyes do not get a good rest. Outdoor sports can effectively relax children's eyes, reduce children's visual fatigue, but also be more conducive to the healthy development of children's bodies and minds.
How do myopic glasses work?
The formation principle of myopia is that when the light from the outside world enters the eyeball, it is refracted by the eyeball's refractive system and cannot be accurately imprinted on the retina. The image is in front of the retina. If a concave lens is placed in front of the eye before the light enters the eye, it shifts the focus of the myopic eye from a point in front of the retina to the back, so that it lands directly on the surface of the retina. When parallel light passes through a concave lens, it diverges, meaning that it has already diverged once before entering the eye and then is refracted normally by the eye's refractive system. When the light is refracted through the eyeball, the distance of the image will be longer. So the distance of the image will be correspondingly pushed back compared to the non-divergent light. But it will just fall on the retina, and the image will be accurate in the right place.
Rimless Glasses 393014
They are not heavy, with a nose pad and spring hinge. It is a metal alloy frame, and it has a designer acetate temple. This pair of glasses show lens shape #226. These different lens shapes and selection of size can greatly change the overall look and final size.
Frame Selection of Progressive Sunglasses
Choose a proper frame range. Only if the frame is not very large and beveled, the frame can be very flat. Because the distance from the glazed to the optical center of a progressive multi-focus lens is 19-17 mm, and the distance between the edges of the frame will be no less than 28 mm if the area inside the lens can be used at close range while maintaining the far sighting field.
Are titanium glasses really more expensive?
Due to its lightweight, corrosion resistance, non-allergic and memory quality, titanium is becoming a new type of glass frame material. But titanium frames are more expensive than other metal, sheet, or plastic frames. Titanium is not a rare metal. It has the fourth-largest reserves after aluminum, iron, and magnesium, and is 16 times more than the world's copper, nickel, leads, and zinc combined. Scarce resources are supposed to have higher prices. With so much titanium in store, why would titanium frames be more expensive than frames made of other materials?
Cheap reading glasses can cause eye strain.
The optical quality of cheap reading glasses is often not as good as that of custom glasses for computer use and reading. Moreover, cheap reading glasses often offer no protection against the high-energy blue light emitted from computer screens and other digital devices.