Progressive lenses and single vision lenses
Single vision lenses are the most commonly used prescription lenses. This lens type has a single field of view or a prescription ability of the entire lens and can be used to correct myopia (nearsightedness) or hyperopia (supervision).
Progressive multifocal lenses are lenses with different upper and lower powers for the upper part to see far, and the lower part to see near. The distance from the fixed power above the lens to the fixed power below the lens does not change suddenly, but there is a gradual transition between the two through the gradual change in refractive power.
Design principle of aspheric lens
Early optical lenses use spherical lenses. Because the glasses were small round frames, the problem of lens edge aberration was not paid attention to. It wasn't until large frames became popular that the problem became apparent. For the spherical lenses, aberration cannot be corrected with the combined lens. Only a few variables of the lens can be found to reduce aberration and improve clarity. Aspheric lenses are designed to reduce the aberration of optical correction lenses and to make lenses flatter and reduce lens magnification. We can get clearer, thinner, lighter-quality lenses. Thus, aspheric lenses are used to reduce aberration and astigmatism to a minimum, close to the natural vision of the naked eye. The spherical aberration can be reduced by changing the curvature of the edge. The refraction in the central region is high and decreases evenly toward the edges.
Titanium frame machining is complicated.
The elastic modulus of titanium alloy is small, which is easy to produce large deformation, springback, distortion, and vibration in cutting, resulting in poor geometric shape and accuracy of the workpiece. As the surface roughness increases, the tool wear increases. The thermal conductivity of titanium alloy is poor and its thermal conductivity is small, 1/6 of that of 45 steel, so the high heat generated in processing cannot be effectively diffused. It is even harder to use titanium to make glasses. The frames are very thin and a lot of fine work is demanded. It's definitely a challenge for titanium, which is pretty difficult to work with. In addition, titanium alloy frames involve titanium alloy welding technology, which is more difficult.
Tortoiseshell glasses are abundant in variety.
Tortoiseshell glasses frame is quite rich in color. Black, brown, light gold, and other colors are covered, with black spots scattered at random distribution. The overall color is dark. Regardless of men and women, it will add a noble and steady feeling to the wearer. For many people, today's tortoiseshell glasses wear, is not only for the pursuit of its own comfort. It is more as a kind of decoration, showing their extraordinary taste.
How To Use Contact Lens Correctly?
It is not recommended to use contact lenses when they are dry. Because when they are dry, even the nursing vacuole is used, the parameters change. It will affect the comfort of wearing, so it is recommended to replace the new lens. After the nursing liquid is used every time, you should cover the lid tightly. Do not touch the mouth of the bottle with your hand. If expired and unused, it should be discarded and replaced with new nursing fluid. As for your discomfort, you should return to the store for inspection.Contact lenses and glasses should be used interchangeably.
Do night driving glasses really work?
Yellow lenses reduce the amount of light entering your eye, reducing visibility. These darker colors block more blue light than yellow lenses. But they block more light from entering the eye, reducing visibility even more in low-light conditions. In fact, even yellow lenses reduce overall visible light to some extent because they block some blue light. This can be a good thing during the day, but not at night, when maximum visibility is key. Night driving glasses come in a variety of yellow and amber colors. The darkest lenses filter out the harshest light, but they filter out the largest amount of light, making it difficult to see in dim or dark conditions. Some people who wear night driving glasses say they can see better with them on. However, vision tests have shown that night driving glasses do not improve night vision, nor do they help drivers see pedestrians any faster than they would without glasses.
Sports goggles
With the improvement of people's sports concept and sports protection concept, sports goggles are also widely welcomed. Safety glasses are worn during sports must have four major functions, safety (PC lenses), protection (TR-90 frame, soft and flexible), comfortable (non-slip nose pads and foot covers), and beauty (match sports and leisure clothing).
Sports goggles with shatter-resistant plastic lenses and side shields can prevent balls or sand from hitting the eyes. It can be fixed on the head without worrying about falling off during intense movements. The unique design of the rim of the frame makes the glasses very close to the human face and has a proper external isolation effect so that the human eye is not easy to be attacked by bacteria. The special lens has the functions of anti-fog, anti-shock, and ultraviolet rays, which is very suitable for outdoor activities.
