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.
Qualified Optical Shop
Qualified opticians are determined not to sell substandard glasses. It is not recommended to keep the lens frames unless the same type can be found. If not, customers will be told directly that the data is likely to change. Optical shops using imported edge grinding machines can better ensure the accuracy of the data of the glasses. The processing engineer must pass a strict examination before he will process glasses for customers. And each pair of glasses needs another person to check, and then pass to the customer to wear. When customers take glasses, they should be informed of the correct steps for cleaning glasses.
What are polarized lenses for?
Polarized lenses contain a layer of polarizing plates in which molecular chains form a light-grating structure in which dichromatic pigments, which absorb polarized light, are evenly distributed. A beam of light is absorbed when it vibrates in the same direction as the bars of the molecular chain of the polarized lens. The grating direction formed by the molecular chain of the polarizer is the axial direction of the polarizer, which is generally horizontal. When polarized lenses are worn, they absorb all the light that vibrates horizontally, thus absorbing the glare and preventing it from reaching the eyes.
What Are Computer Glasses?
Computer glasses or glasses for computer are prescription glasses that are designed to wear when doing computer work. They allow you to focus your eyes on a computer screen. There are other activities such as playing piano or shooting requiring a similar custom fitting.
Glasses for computer use are also known as blue light glasses. They block blue light that causes eye strain due to prolonged viewing of digital screens. Blue light is part of the color spectrum, and everyone is exposed to it through sunlight.
The glasses for computer use have a shorter wavelength than other colors and are emitted by electronic devices such as smartphones, TVs, computers and more. The glare from blue light is what causes digital eye strain or other symptoms. But the glasses for computer can protect your eyes from the damage of the glare.
Depending on an individual’s vision and type of work, there are several options while selecting glasses for computer use.
Monofocal: Monofocal or single-vision glasses are designed for computer work so that they provide the appropriate optical correction for the working distance between the screen and the user’s eye. These glasses allow users to view the whole screen with a minimum up-and-down head movement. However, the disadvantage of the monofocal glasses is that both distant objects and reading materials that are closer than the computer screen will appear blurry.
Bifocal: When it comes to glasses for computer screens, the bifocal glasses would be a choice. Bifocal glasses can be prescribed so that the upper segment is set up for screen distance and the lower segment for work. The disadvantage of these bifocal glasses is that it will blurry if the objects are farther away than the screen.
Trifocal: These trifocal glasses for computers have lenses that combine a segment for far vision, another for near vision and the third one for at the screen distance. The disadvantage of these glasses for computer screen is the limitation to view areas.
Design and Fashion of KOALAEYE Eyewear
Women's glasses, which are functional and sexy, can add so much to an outfit and even serve as a personal expression. So, it's only natural that you're looking for new frames to add a bit of style to your everyday outfit. Light, flexible and colorful, the attractive style can effectively modify the shape of the face and has become the choice of more people. The production process is complex and the design looks simple. As a classic product, the plate series is enduring. As the tide and fashion style change, its position will not change. With different styles, the feel and appearance are better. They can effectively reduce the pressure of the bridge of the nose. The stylish style is popular with most people.
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.
What characteristics do children's glasses have?
The lens degrees need to change with the degrees of the eye. Because children are still in the process of growth and development, especially preschool children and adolescent children. Preschool is the key period of visual development, and farsightedness is slowly reduced. The eyeball development is close to an adult. Adolescence is the second peak of eyeball development, and myopia is most in this stage and little by little deepens, stopping at the end of adolescence.
