What difference do mono-focal glasses and multi-focal glasses have?
A mono-focal lens is a lens with one focal point. Usually, the myopic far-sighted presbyopia that we see belongs to mono-focal glasses. There is only one diopter on one lens, and this is the single focal point. Multi-focal glasses are lenses that have multiple focal points, that is, multiple diopters. Both mono-focal glasses and multi-focal glasses are visual correction tools, but mono-focal glasses can meet basic vision needs, like fatigue relief, control of depth of diopters, and focus on different distances such as the need to see far and near.But because there are many different diopters on a multi-focal glasses lens, so the elderly can not only see far after wearing. When they see close distance, they do not need to take off glasses or wear reading glasses. Wearing multi-focal glasses is not easy to fatigue.
What are optical frame glasses?
Optical glasses are transparent medium lenses. A pair of glasses usually consists of a lens, lens ring, nose pad, and temple, etc. The main materials are metal, plastic or resin, natural materials, etc. Through the refraction of the light, the central target can be clearly seen, thus playing a role in vision correction for the eyes with refractive abnormality.
Crystal clear eyeglasses
The trend is to make everything bright and clear. Frame shapes can be small and round or thick. Some have subtle colors like blue or gray, which makes the glasses look more jewel-like. Whichever you choose, a clear frame will help improve your style. Transparent, translucent frames have gone from being a bold fashion statement to a common, versatile option in the last few years, and now eyewear has more options than ever before. These frames vary from heavy traveler style to a more elegant corner frame to balance out your facial features. No matter what color or hue you choose, these clear frames show off your personality.
Bifocal vs Varifocal Glasses: What Are Their Differences?
The above part has introduced some basic information about bifocal glasses and varifocal glasses. So, what are their differences?
- Bifocal glasses have two different prescriptions in one lens, while varifocal glasses have three different prescriptions in one lens.
- There is a distinct line between different prescriptions in bifocal glasses. Varifocal glasses allow getting through other prescriptions smoothly.
- Varifocals can give you a vision at any distance.
- Bifocal glasses are more cost-effective than varifocal glasses.
However, they also have some similarities. Both glasses can be used to correct presbyopia vision. So, when you choose glasses, you can decide to choose bifocal glasses or varifocal glasses based on your needs. If you want to get a pair of corrective glasses online, Koalaeye Optical is recommended. It is an online glasses store and provides all kinds of eyeglasses, sunglasses and frames. In addition, these glasses are stylish and come at a cheap price.
Why Are My Progressive Lenses Blurry?
Progressive lenses are optical lenses designed for simultaneous correction of far, medium and near. Progressive lenses use polishing technology to achieve a gradual transition between the two focal lengths. With progressive lenses, people do not have to switch their glasses for different purposes.
However, with the usage of progressive lenses, there are some problems of progressive voices. One of the most commonly reported side effects of progressive lenses is blurry or fuzzy peripheral vision. The blurriness is usually most noticeable through the lower portion of the lens and to the left and right of near and immediate zones.
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.
Different Types of Eyeglass Frame Materials
Titanium: as for metal frame material, Titanium is one of the most popular ones. The titanium frame material can be bent and twisted and then come back to its original form. The quality of these frames is durable and reliable for rough use. The Titanium frame material is light.
Flexon: Flexon is a titanium alloy that is composed of around 50% titanium and 50% nickel. Flexon eyeglass frames are extremely flexible and can be twisted or bent to an extreme and can return to their original shape. The flexon frame material is popular among kids' glasses.
Beta titanium: this is an alloy mainly composed of titanium and a small amount of aluminum and vanadium. The beta-titanium has a memory feature and is mostly used in high-quality designer frames. The beta-titanium is toughness and light.
Monel: it is an alloy of nickel and copper. The monel frame material is cheap and discolor.
Beryllium: it is an alternative to titanium resisting corrosion and tarnishing, but it is cheap. The beryllium frame material is lightweight, strong, flexible and available in a wide range of colors. In addition, it is a good choice for those people with high skin acidity or those people who spend a large amount of time in or around salt water.
Besides the above plastic eyeglass frame materials and metal frame materials, there are some other frame materials available, such as aluminum, gold, silver or other biodegradables materials. You can choose the suitable one according to its performance, features, and price.
What’s more, you can choose glasses from Koalaeye Optical. It provides various kinds of glasses and frames, such as blue light blocking glasses, rimless sunglasses, and so on.
