Identify the lenses of discount glasses
Look at the overall package: let him show you the overall package of the lens. See that if the factory is in China, Shanghai, China, or Zhejiang, China, etc. Look at the anti-counterfeiting logo. It doesn't necessarily mean it's good. Check the production plant, address, news, etc. In short, lens judgment, for the average consumer, is difficult, but when you put forward these requirements, the store will at least think you are more professional.
How To Choose Better Night Driving Glasses?
Choose and buy glasses to use a special night with anti - strong night driving lens. The demand is to block 80-90% of the strong lights and harmful lights, and at the same time to make the road more clearly. Choose glasses with thicker lenses, they are more durable and protect the eyes of drivers against irritation and accidental breakage. As common sunglasses and color-changing glasses are only suitable for daytime wear, wearing them at night will seriously affect the driver's vision.
Common light yellow night driving glasses can only block a small amount of light, and is not very suitable for night driving glasses standards. Therefore, in the choice of lenses of night driving glasses, we must do the selection and demonstration of the national authority of the formal institutions to test products, to achieve the desired effect in actual use. Don't buy products that are not up to standards from vendors. Such products not only do not block the lights but may affect the driver to see the road ahead, affecting the safety of the train operation.
Advantages of progressive lenses
1. The appearance of the lens is like a single vision lens, and the dividing line of the degree change cannot be seen. Not only is the appearance beautiful, but more importantly, it protects the age privacy of the wearer. There is no need to worry about leaking the age secret due to wearing glasses.(https://www.koalaeye.com/collections/progressive-glasses)
2. Since the change of lens power is gradual, there will be no image jump. It is comfortable to wear and easy to adapt.
3. Because the degree is gradual, the replacement of the adjustment effect is gradually increased according to the shortening of the short distance. There is no adjustment fluctuation, and it is not easy to cause visual fatigue.
4. Clear vision can be obtained at all distances in the visual range. A pair of glasses meet the use of long-distance, near use, and various distances in between. It is especially good for teachers, doctors, music workers, and computer operators because these people not only need to see far and near objects clearly, but most of the time they also need to be able to see objects at intermediate distances such as blackboards, piano scores, and computer screens. This is not possible with lenses other than progressive lenses.
5. At present, both internal and external ophthalmologists agree that young people should wear low-degree convex lenses when reading and writing to reduce near-use adjustment, thereby alleviating or preventing the occurrence and development of myopia. This gives the progressive multifocal lens a new meaning and mission. Physiology found that excessive use of the eyeball adjustment function can form 'accommodative spasm' or pseudo myopia. Continued development can produce longitudinal eye axis elongation and induce 'true myopia' or axial myopia. The external luminosity of the progressive lens can be artificially added to the progressive luminosity. The upper is used for looking far, and the below is used for looking near, which makes the eyeball relax and over-adjust. The ever-changing luminosity of the lens replaces the 'accommodative power' that should have been activated, blocking the vicious circle of adjusting the eye axis elongation, making the eye not easy to fatigue, and slowing the development of myopia.
How to Choose Reading Glasses?
If you need reading glasses when using a computer, you may want to choose a lower reading glasses power. This is because most people view their screen from a greater distance from their eyes than when they are reading a book or a magazine.
However, if you need reading glasses for looking at something very close or very small, you may need a pair of stronger power glasses.
In most cases, when two reading glasses’ powers seem equally suitable, choose the glasses with the lower power. Picking reading glasses that are too string typically will cause more discomfort problems than reading glasses that are a little too weak.
What Is Polycarbonate Lens?
Polycarbonate was developed in the 1970s for aerospace applications and is currently used for the helmet visors of astronauts and for space shuttle windscreens. Polycarbonate lenses were introduced in the early 1980s in response to a demand for lightweight, impact-resistance lenses. Since then, polycarbonate has become standard for safety glasses, sports goggles, and children’s eyewear.
Polycarbonate glasses are thinner and lighter than regular plastic lenses. They provide 100% UV protection and are up to 10 times more impact-resistance than plastic or glasses lenses. Polycarbonate glasses also offer clearer and more comfortable vision if an anti-reflective coating is applied to the lenses, which can eliminate distracting lens reflections that interfere with vision, particularly when driving at night or in other low-light conditions when glare sources are present.
However, polycarbonate lens is a naturally soft material, making it more subject to scratching without adequate protection with a scratching-resistant coating. Polycarbonate glasses have high dispersion due to its low Abbe value of 30, causing chromatic aberrations.
Sometimes they need to be adjusted by professionals.
Some connecting parts of glasses will be loose, but some people do not care about them and make casual changes. In reality, the change of the lens frame is very technical. The distance between the lens and the glasses will affect the effective strength of the lens, so the adjusted glasses need to be 12 to 14 mm away from the eye. The optical center of the lens should be aligned with the pupil position, and the nose pad, the temples should be consistent with the contact part of the bridge of the nose and the ear, without pressure and pain. Therefore, the lens frame must be adjusted by a professional optician. Especially some special lenses (progressive multi-focus glasses) need to be repaired regularly.
Consider possible uncertainties after the lens is installed.
Usually, in-store frames are made of plastic samples rather than actual lenses, so they weigh slightly less. However, it is necessary to consider the approximate weight of the lens in advance according to its own degree when trying it on, in case the weight is not suitable for real wearing. If the pupil distance is too small, it is not suitable to wear a wider frame. The machinist should strictly follow the left and right pupil distance instead of taking the average, otherwise, there will be pupil distance error in the left and right eyes, which will cause discomfort in wearing.
