Choose clear glasses for kids of suitable temples and nose pads.
Children's head is very different from adults, especially the height of the bridge of the nose. Most children's bridge of the nose is low. Therefore, it is best to choose a high nose pad for children's glasses or an adjustable eyeglass frame for the nose pad. The temples of the glasses should not cause uncomfortable pressure and the glasses should be kept in the correct position. Sporty temples are another option. The temples are very flexible, and they fit well into a child's ear. It should extend to the earlobe and be covered with soft plastic.
How to Choose Reading Glasses?
Find the right power. When choosing reading glasses, finding the right power would be the most important thing. All reading glasses will have signs or stickers indicating their power. In most cases, they will range from +1 to +4 diopter, in increments of +0.25. So, when choosing reading glasses, try the lowest power first.
Test-drive the glasses. If you have brought reading material with you, try reading it at a comfortable length. If you hold the material too far out to be able to read it, you should increase the power. Keep testing the differences powers until can read clearly at the distance that’s more comfortable for you.
Metal Eyeglasses
Whether you like classic looks or prefer rectangular and functional things, all metals will look new in 2021. Combining the trend of super large frames, you get a big round metal frame. These styles are not heavy and fit all face shapes, from round to square, and anything in between.
Parameters of lens material selection
Abbe number
Since the refractive index of the lens material varies for the light of different wavelengths, and white light is made up of various colors of light of different wavelengths, the dispersion phenomenon occurs when the lens refracts white light. The dispersion coefficient is an important index to identify the sharpness of lens imaging, which is usually indicated by Abbe number (Abbe number = dispersion coefficient). The larger the Abbe number, the smaller the dispersion, and vice versa, the smaller the Abbe number, the larger the dispersion, and the worse the resolution of the image.
Impact resistance
Humans have been using glass lenses for about 300 years, and it was not until 1947 that the first resin lenses made of CR39 were produced. A big reason for using resin lenses is their safety, i.e. impact resistance. Only lenses that pass the Drop Ball Test are considered safe. Combining the above two parameters, we can compare different lenses.
How to buy contact lenses online?
Choose the right contact lens for your situation. Base arc and degree need to be added in the hospital or optician shop to determine. Try not to buy according to the framed degree. Some businesses claim to have the lenses having South Korea's silicone hydrogel, with annual throwing. They are not to be believed, because the material characteristics of the silicon hydrogel are not capable of making long-time discarded type lenses. There are a lot of things to pay attention to in order to properly wear contact lenses. For example, a medical optometry sheet is the premise of attention. Each pair of contact lenses is marked on the package of the basic arc, diameter, water content, diopter, and other parameters. Only according to the optometry sheet, you can choose the correct basic arc, diameter, and diopter. At the same time, there is a certain distance between the glasses and the cornea.
Different Types of Eyeglass Frame Materials
Acetate: The most popular frame material is acetate, also called Zyl. Zyl is a very cost-effective and creative option for eyewear and is extremely lightweight. The acetate frame material is also colorful.
Nylon: This frame material is used in some cheap eyeglasses. Nylon is strong, lightweight and flexible, and it can become brittle with age. Nylon is also a premier material for sports and performance frames, and also easily molded into today’s popular wraparound style.
TR90 Nylon: TR90 Nylon is durable, flexible, and lightweight. Glasses made with TR90 are extremely comfortable since they have a flexible quality. Besides, the TR90 Nylon frame material can bend under pressure and contour your face comfortably. So, it would be resilient to damage.
Ultem: Ultem resin is a flame-retardant and high performance thermoplastic. It comes with various features, such as high strength-to-weight ratio, heat resistance and high impact strength. This frame material is also durable.
Do Blue Light Glasses Work?
When wearing blue light glasses, you may ask whether the blue light glasses really work. In fact, many users have the same troubles. To answer this question, some researchers have made research and have found that blue light glasses make it possible to remain fully engaged in our technologically advanced world, without taking on the negative effects of blue light.
With the blue light blocking glasses, you can focus on the task at hand without negative effects. Besides, with the blue light blocking glasses, you can even sleep well and reduce eye strain. You can also test your blue light glasses are real.
