[Professional Technology] Sunglasses Knowledge Summary
What is ultraviolet light?
Invisible light with a wavelength between 200 nm and 380 nm is called ultraviolet light, which has a lot to do with the health of our eyes. The higher the UV intensity, the greater the chance of cataracts, keratitis, macular degeneration and plaque in the eye.
What color sunglasses lens shading effect is better?
From a visual point of view, the shading effect, the color of the lens with better definition of the object are gray, dark green and brown lenses, and the light-colored sunglasses of other color lenses will be more decorative.
The lens indicates UV400 or 100%. What does the UV index mean?
The lenses marked with UV400 or 100% UV are specially processed to completely block all UV rays with a wavelength of less than 380 nm, which can fully protect our eyes. When buying sunglasses, pay attention to whether there is a corresponding mark to block UV rays. UV index: For sunglasses, the UV index is also the effect of filtering ultraviolet light, it should be to eliminate the light band of 280-400nm. At present, the UV index of most sunglasses is between 96% and 98%, and dark lenses are better than light lenses.
What is a polarized lens?
A polarized lens is a special lens that adds a vertical special coating to the lens, allowing only light in a certain direction to pass, filtering the glare of the sun in the equal direction on the surface of the water, land or snow, making the light soft. Comfortable and able to reduce glare and see objects more clearly. Polarized lenses can reduce the glare feeling caused by asphalt roads, glass walls, water surface and snow. They can also eliminate reflection and glare. At the same time, they can enhance the contrast of scenes and have excellent anti-glare ability.
How to identify polarizers?
The simplest and most effective method: the first one, after the two polarizers are vertically stacked, the scene behind the lens is completely invisible; the second one is identified by the glare demonstrator.
What are the types of polarized sunglasses?
Polarized sunglasses of different colors each have different characteristics. Gray or dark green lenses, which are the most natural choice when viewing objects, are good choices. Brown or brown lenses are the lens of choice for driving because they enhance color contrast. Amber, yellow or orange lenses are perfect for wearing on cloudy days and can have a very clear view, but not suitable for use under the sun. The light red or vermilion lens can deepen the contrast and sharpness when the glare is strong, making it ideal for water sports and snow activities. In particular, the color of the lens only affects the absorption of visible light, and has nothing to do with the ability to resist ultraviolet rays.
What do you need to know when buying sunglasses for children?
(1) Spectacle frames must not have sharp edges and should not be easily damaged, otherwise your child may hurt himself while playing.
(2) Select high-quality spectacle lenses. For safety reasons, children’s sunglasses should only use shatterproof resin lenses and UV400. For adults and children, wearing sunglasses can cause eye pupil enlargement. If the sunglasses lens does not provide adequate UV protection, the dangerous UV rays will penetrate unimpeded and, in some cases, cause permanent damage.
(3) Choose sunglasses that fit your child’s face. Children are not yet able to judge for themselves whether the glasses are fit or not, or if the glasses are too tight or uncomfortable. You should use the experience of an optometrist to help you make your choice. Experts will definitely formulate the most suitable sunglasses for your child’s face. Tip: To ensure that children are really willing to wear sunglasses, let the children help them choose sunglasses.
By the way: sunglasses are not suitable for too small babies. Their noses and ears have not yet developed enough to wear glasses. The best protection for babies is to loosen their caps or keep them in a cool place. Children should have their own sunglasses at the latest when they start to enter preschool.
Everyone can choose different types of sunglasses solutions according to their needs:
(1) Use sunglasses clips, you need to go to the regular optical shop, choose the appropriate clip according to the size of the different frames; there is also a set of mirrors on the market, that is, there is a pair of glasses outside the frame glasses that exactly match the lens ring. The sunglasses set mirror is fixed by the magnet on the frame frame. Although the appearance is greatly improved compared with the clip, the weight of the glasses is increased.
(2) Using resin dyed lenses to make myopia sunglasses, which has high professional requirements for optical shops, requires professional optometrists to perform optometry examinations on consumers, so that the fitted myopia sunglasses can achieve the best visual effect.
(3) Using the color-changing lens, it can be transparent and colorless in the room, and the color of the ultraviolet lens becomes darker, thereby blocking the ultraviolet rays, improving the visual effect and helping to weaken the glare and making the eyes easier.
For consumers who do not have optical expertise, the following methods can be used to easily identify the intrinsic quality of the lens:
(1) The degree of the lens should meet the requirements for flat lenses, and there should be no optical defects that affect vision. The simple identification method is that the sunglasses can be placed in front of the eyes, and the distant objects, such as window frames or door frames, are observed through the lenses, and then the glasses are moved up and down, and the target should not have wobble and wave deformation. It is also possible to observe the tube image on the surface of the lens of the sunglasses under the fluorescent lamp, and move the sunglasses to make the image of the tube appear in different parts of the lens, and the image of the tube is not deformed to be optimal.
(2) The color of the lens should not be biased, so the color of the surrounding environment should not be distorted. Before wearing sunglasses, observe objects such as red, green, and yellow, then put on sunglasses and observe the same object. The color of the two observations cannot be color cast, otherwise the ability to recognize traffic lights will be reduced. Special attention should be paid to the identification of sunglasses with colored lenses.
Two ways to identify and choose sunglasses:
First, see the product identification
Pay attention to whether the glasses are marked with anti-UV function and anti-shock function. Because not all sunglasses can protect against ultraviolet rays. If there is sunglasses with “anti-UV” function, there should be “100% anti-UV” and “UV400” on the front of the product label or glasses. If it is a “anti-shock” function, it should have “attack performance”, “through the US FDA certification”, “conform to the highest standards in Europe and America” on the label or the manual. At the same time, these logos or instructions should be kept in good condition in case of problems.
The second is to observe the quality of the lens
When the sunglasses are placed in front of the eyes, look at the distance through the lens, move the glasses up and down, left and right, the target should not swing, the lens color is stable. Looking through the lens, the color of the surrounding things is not distorted, and has the ability to recognize different color signal lights. The color of the sunglasses is not very helpful in resisting the ultraviolet rays. In addition to pursuing the beauty and recognizing the logo, the sunglasses should also pay attention to the protection of the sunglasses. The good sunglasses can effectively block the ultraviolet rays and glare, and can reduce the bright and harmful ultraviolet rays. UV) Light and glare damage to the eyes. Polarized lenses, anti-reflective lenses, etc. can make sunglasses better reduce glare, anti-reflection, increase object contrast in foggy and cloudy days, and make the field of vision clear.
Use and maintenance of sunglasses
(1) The method of maintaining the sunglasses is like maintaining the general glasses. It is necessary to develop the habits of cleaning, stacking and storing. In addition, sunglasses are often worn off, and the lenses are easily scratched, so some small details should be paid special attention: when there are stains on the sunglasses, do not use your nails to scratch, which is easy to scratch the surface.
(2) When the sunglasses are not worn, put the sunglasses on the head or hang on the collar and pocket, which may cause the sunglasses to be torn or damaged. If you put the sunglasses in the bag, it is recommended to put them into the hard glasses case and put them into the bag to avoid being rubbed by hard objects or contaminated with cosmetics.
(3) It is very bad habit to drive sunglasses on the dashboard or in the seat. Sunglasses can be deformed by baking in hot weather, especially plastic frames, preferably with a car or in a spectacle case.
(4) Regardless of where you collect your sunglasses, be sure to remember that the mirror is facing up.
Who should not wear sunglasses?
(1) Glaucoma patients: due to the aqueous circulation disorder, the intraocular pressure is increased, causing the optic papilla to shrink and the visual field to be deficient, resulting in decreased vision. If you wear sunglasses, the pupils will be enlarged, the pupils will be enlarged, and the water circulation disorder in the eyes will be aggravated, so that the already high intraocular pressure will be further increased, which will not only worsen the condition, increase the suffering of the patients, and even cause blindness.
(2) Patients with optic nerve retinitis: wearing sunglasses in this patient will aggravate the conduction disorder of the optic nerve and is not good for rehabilitation.
(3) Color blind patients: full color blind wear sunglasses without serious problems. However, due to the fact that all-color blindness is rare, most of them are partially color-blind, and they lack recognition ability for several colors. Wearing such sunglasses can make color discrimination more difficult.
(4) Night blindness patients: In the elderly with night blindness, because the long-term intake of vitamin A is insufficient, the retinal that participates in the dark visual reaction in the body cannot be effectively supplemented, so in the dim light, the patient’s vision will be affected. Not suitable for wearing sunglasses.