Size of the glasses frame
Children's glasses should have enough field of vision. Because children have different kinds of activities, try not to choose frames that will produce shadows and blind corners. If the frame is too small, the field of view will be smaller. If the frame is too big, it will be easy to wear instability, and weight will increase. So the frames for children should be moderate in size.
Acetate frame and plastic frame
What is the difference between acetate frame and a plastic frame? Acetate frames are lighter and generally considered to be better than plastic frames. Acetate is known for its hypoallergenicity, so it is a popular choice for people with sensitive skin. Unlike some plastic or metal frames, they can cause allergic reactions.
- The manufacturing process makes the plastic frame more brittle than the acetate frame.
- If the temple does not have a metal bracket, it is difficult to adjust the plastic glasses.
- There are fewer choices of colors and patterns for plastic frame
However, you will notice that acetate frames are generally more expensive than ordinary plastic frames. Spectacle frames are daily necessities that we use for a long time. Therefore, durability is essential, and the life span of the acetate frame is longer.
How do you buy prescription glasses on GlassesUSA?
Fill out a form on their website to enter a prescription, choose to have them follow up and require it later, or use their prescription scanner app on an existing pair of glasses. However, the app isn't always easy to use. You'll need your phone, a computer with enabled cookies, your glasses, and a magnetic stripe card to determine the size.
About Polarized Sunglasses
Polarized sunglasses only absorb the reflected light of the object itself, presenting what is being seen, making the field of view clearer and thus reducing eye strain. In addition, the light through a bumpy road, water, and other places also can produce irregular diffuse light. The polarized lens can be this kind of optical filter, only absorbing the reflection of the object itself. Because of its high-efficiency filter layer, the UV blocking rate of the polarized sunglasses is 99%, which can effectively reduce UV damage to the eyes. And if you are driving, fishing, traveling, skiing, it is recommended to choose more powerful polarized sunglasses.
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 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.
Try to avoid wearing the following glasses.
If you need to wear glasses while driving, you'll need special glasses when driving at night, because common lenses reflect oncoming lights, which produces a faint glare. This will reduce your visibility. It's OK to wear contact lenses while driving. As you get older, your eyes become more sensitive to glare. Ordinary sunglasses or goggles are only suitable for wearing during the day, driving at night will seriously affect the vision (national standards stipulate that light transmittance of night driving glasses must be greater than75%). Although the all-weather driving glasses can weaken the strong lights, the vision darkens and affects road safety which does not meet the national standards for driving glasses at night. You should choose functional driving glasses that can block strong light, glare and increase the field of vision. This can effectively reduce the glare of the car lights but can filter out the extra harmful light. When worn at night, it can soften the strong lights and make the vision clearer. In this way, the safety of drivers is ensured, the fatigue of eyes is alleviated, and the radiation damage of harmful lights to glasses is prevented.
