The lenses of prescription glasses
Common materials for lenses include glass, resin, and PC. The glass is fragile and heavy, and few people wear it anymore. PC film is tough and not fragile, but it is not resistant to high temperature and the surface is easily scratched. The most common type of lens on the market today is the resin lens, which is light in weight, hard to break, and reasonable in price. At present, it is generally recommended that you choose resin sheets, and it is recommended that people with ultra-high myopia choose glass sheets.
Generally, lenses can be divided into spherical and aspherical surfaces according to different curvature designs. When choosing, refer to the degree of the eye. For people with lower degrees, There are fewer differences between the two shapes. For people with moderate to high myopia, aspherical lenses will have better imaging effects and clearer vision.
When choosing a lens, a parameter that is often mentioned is the refractive index. Common refractive indexes are 1.56, 1.60, 1.67, and 1.74. With the same degree, the higher the refractive index, the thinner the lens.
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.
The advantages are not the same.
The cellulose acetate frame is acetate plastic, belonging to a kind of thermoplastic material, and it is a material for nearly 20 years. It is widely used in the glasses industry material. Now with the progress of processing technology, it can be divided into plate and injection molding. The acrylic frame of the propionic acid fiber belongs to a kind of thermoplastic material. The appearance is transparent. The main feature is that the material density is high. They are hard to burn and are not easy to change color, with Impact resistance. It has softness, dimensional stability, and good processing formability. Many high-grade plate glasses are based on these high-quality plates, so the quality is more reliable. It is designed for a large number of people and the pursuit of quality of life students, especially for women.
Step-by-Step Glasses Size Guide
In this section, we will show you how to perform glasses measurements. But the first thing is to know what face shape you have. If you do not know, click here to have a check.
Then you need to know where to find the size measurement of your glasses. In general, you will find numbers that look like this 51-17-145 at the temples of your eyeglasses. Of course, these numbers come at different meanings.
The first number often refers to the lens width. Lens width is the horizontal diameter of the lens at its widest point. In optometry, another term is eye size.
The second number often means the bridge width. Bridge width is the part that joins the two lenses and sits over the nose. Some refer to this as the gap. The bridge width varies between 14 and 24 millimeters.
The third number often means the temple length. The temple is the arm that keeps the sunglasses on your face. That arm extends to the part that hangs on the ears. The length is usually 135, 140, or 145 millimeters.
Lens height measures the size of the lens vertically, that is from the top to the bottom of the lens. Although sizes may differ depending on the brand, the standard size is somewhere between 32 and 38 millimeters.
How to choose blue light blocking glasses?
Nowadays, electronic products such as mobile phones and computers have become indispensable tools in our lives. While these high-tech products bring us convenience and fun, they also bring symptoms such as eye fatigue and myopia. Subsequently, blue light blocking glasses have also received everyone's attention. Anti-blue glasses are only suitable for people who use electronic products for a long time, not for people who are visually fatigued. Exposure to such unnaturally strong blue light for a long time every day, especially for teenagers and children, needs to pay more attention to the prevention of blue light. So, how to choose suitable blue light blocking glasses for kids?
Anti-blue light is necessary, but not all blue light can be filtered out, because blue light will interfere with the body's melatonin secretion after being over-filtered, thereby affecting sleep. Therefore, when choosing blue light blocking glasses, you should choose appropriately according to your own eyes.
For how to choose anti-blue glasses, consumers can distinguish from the color of the lenses. Generally speaking, a lens with a yellow color will have the effect of blocking blue light. But too dark lenses will affect the contrast sensitivity. Therefore, it is recommended that consumers choose moderately. In addition, consumers should also pay attention to whether the glasses products (lenses, frames) have conformity marks, etc. It is best to choose professional and well-known glasses shops to match glasses.
How to Adjust Crooked Glasses
If one side of your frame looks higher than the other, you need to adjust the arms of your glasses. So, how to adjust glasses?
If the right side is higher than the left, you need to gently bend the left arm down at the hinge or where the arm bends behind your ear. If the left side is higher than the left, so just do the same action on the opposite side.
When adjusting crooked glasses, you need to adjust frames a little bit at a time to avoid overcompensating and possibly damaging your glasses. You can run the arms under the warm water but do not running the warm water over the lenses because it will affect the lens coating.
The most popular scratch-resistant coating packing is about $30.Nikon Eyes Advanced includes stain-proof and water-resistant coatings, plus high-definition digital lenses, and a two-year limited coating warranty, and the price is about $120.Nikon Eyes Customized includes all the benefits of the Nikon Eyes Advanced package, plus thinner and lighter lenses, with the price of about $150. If you opt for standard shipping, your new glasses will arrive in about a week, but you can filter out second-day delivery, two days delivery, or free pick up today.