Suggestions for Using Varifocal Glasses
If it is difficult for you to get used to the new varifocal glasses, here are some suggestions for you.
1. Wear the varifocal glasses consistently so as to let your brain learn how to use them.
2. The most common accident is tripping when getting used to new varifocal glasses. So, you can mix up your routine to keep your brain active and prevent you from tripping up.
You can also ask those who wear varifocal glasses to give you some advice.
Production technology of progressive lenses
In addition to the evolution in design, the production technology of progressive lenses is also constantly improving: the most representative one is the free-form technology. The emergence of free-form surface technology makes the production more flexible and rapid and can realize a more personalized design. For now, progressive lens design is done on the inside surface of the lens by a computer-controlled lathe, as if a master engraver could carve a piece of stone into a work of art.
Different types of nose pads for glasses
The fixed nose pad is usually used on the plate frame. The nose pad and the frame form an organic whole. The maintenance is more convenient, unlike the movable type that should often twist a screw. It is not easy to hide dirt and dirt. But the disadvantage is that the angle of the nose pad can not be adjusted, and it can not fit the bridge of the nose greatly. The movable nose pad can be automatically adjusted up and down according to the shape of the bridge of the nose to ensure that the compression part of the bridge of the nose is evenly stressed and the local pressure is reduced. But the disadvantage is to often check the tightness of the screw, but often scrub clean. The silicone material usually used in the nose pad is easy to yellow after a long time, which affects the appearance.
The refractive index of lens
Refraction law is discovered by Dutch mathematician Snell.It is the law that determines the direction of refracted light in the phenomenon of light refraction. When the light from the first medium (refractive index N1) into the second medium (refractive index N2), part of the light from the first medium into the second medium at the smooth interface will be refracted. The index of refraction is the ratio of the speed at which light travels in a vacuum to the speed at which light travels in the medium. For glasses lenses, the higher the refractive index, the thinner the lens, that is, the lens with the same center thickness and the same degree, the lens with the higher refractive index has thinner edges than the lens with the lower refractive index of the same material.
Single Vision vs Progressive: What Are Their Differences
In this part, we will show you some differences between single vision and progressive lenses. They differ in several factors, so here we will compare them one by one.
Progressive lenses generally have their reading zones just in the lower half of the lenses, while single vision glasses have the reading power all over the lens. So if you are working on something above your head and you need to see some small details, the progressive lenses will not work. And you can not see through the reading zone in progressive you need to switch to single vision reading glasses.
Single vision glasses are cheap than progressive lenses. Compared to progressive glasses, single vision glasses hold way fewer distortions in the periphery. So, there is no need to customize the lens design to the max. In addition, single vision glasses are often available in the optical store while the progressive often needs to be produced for you. In other words, the delivery time of single vision lenses will be shorter for you.
You can use your progressive glasses optimally just in an upright posture. As soon as you lay down on your couch, this will lead to blurry vision. The reason is your changed position which forces you to look lower through the lenses on the screen. However, with single vision glasses, you can change to an upright position and it would not be a problem anymore. You can position yourself on your couch as comfortably as you want and you can still see clearly with your single vision distance glasses.
The shape of the lens is also important.
Aviator and cat-eye glasses should be avoided, as both will cut off the base of the prescription, resulting in poor reading vision. Instead, they should opt for shorter frames with rounded edges, such as bull horn frames, vintage wingtips, round frames, and oval frames.
Sunglasses have a visible light transmittance of about 20% and can absorb ultraviolet and infrared rays well. It also has a variety of colors such as light green, light gray, light brown, etc., used to protect in different occasions. Among them, light gray lenses have little effect on color recognition. Light brown glasses make the blue sky look darker and reduce the transmission of green light. Light green lenses reduce the transmission of red light.
Sunglasses not only have a wide range of varieties, but with the improvement of decoration and health care effects, their scope of use has become more extensive. As the time to update sunglasses can be rapid, fashionable men and women would love to have multiple sunglasses to match clothes to satisfy their pursuit of fashion.