Midsummer is approaching, the scorching sun is scorching, and with the enhancement of everyone's health awareness, more and more people are wearing sunglasses when they go out. For many friends, the reason for replacing sunglasses is mostly broken, lost, or not fashionable enough...... But in fact, there is another important reason that is often overlooked, that is, sunglasses are "aging and ineffective".
Recently, we can often see some articles reminding that "sunglasses only have a lifespan of two years, and they must be replaced when they arrive". So, do sunglasses really only last two years?
Let's talk about it in detail next.
PART 01
The basic material of the sunglasses lenses themselves can absorb a little ultraviolet rays, and the plating of sunglasses lenses can also reflect part of the ultraviolet rays. In this way, the vast majority of ultraviolet rays can be "kept out" and can no longer harm our eyes.
But this protection is not permanent.
Because ultraviolet rays carry high energy, they will cause the material of sunglasses to age and reduce the ability of sunscreen ingredients to absorb ultraviolet rays. The shiny coating on the outside of the sunglasses is actually the result of metal vapor deposition, and these coatings may wear out, oxidize, and reduce their reflective ability. These will reduce the UV protection of sunglasses.
In addition, if we do not use sunglasses sparingly, it will often cause problems such as direct wear of the lenses, loose temples, deformation and damage to the frame and nose pads, which will affect the normal use and protection of the sunglasses.
PART 02
First of all, I would like to state that this is really not a rumor, but there is really this study.
Professor Liliane Ventura and her team at the University of São Paulo in Brazil have done a lot of research on sunglasses, and in one of their papers, they did mention the recommendation to change sunglasses every two years. This conclusion has also been quoted by many media, and we often see similar Chinese content today.
But there is actually a premise for this conclusion, that is, the researchers calculated it based on the working intensity of the sunglasses in Brazil...... That is, if you wear sunglasses for 2 hours every day, the UV protection of the sunglasses will decrease after two years and should be replaced.
Let's feel that in Brazil, the sun is like this in most places...... After all, it is a passionate South American country, and more than half of the country is tropical......
So from this point of view, most people in the northern part of our country wear sunglasses for less than 2 hours a day. Therefore, we can save a little, and according to the frequency of our usual wear, it is no problem to wear it for an extra year or two and then change it. The suggestions given by some well-known sunglasses or sports sunglasses manufacturers are mostly dependent on the frequency of use, and are replaced every 2~3 years.
PART 03
# Good for eyes and glasses #
Although sunglasses are already a very popular daily necessity, many people's wearing habits have some problems, which not only shorten the service life of sunglasses, but also have an impact on eye health. The following questions, you must pay attention to when wearing sunglasses:
1. Prevent frame deformation
Sunglasses are optical products, and the frame is easily deformed under improper force, which not only affects the comfort of wearing, but also endangers vision and health. Therefore, during the wearing process, it is necessary to avoid the impact or compression of the glasses by external force, and the glasses should be lightly supported on both sides of the temples with both hands to prevent the deformation of the frame due to uneven force on one side, causing the angle and position of the lens to change. If you find that the frame is deformed, you should go to the optical store for correction in time.
2. Keep the lenses clean
Sunglasses need to be cleaned frequently, the specific method: first drop one or two drops of household dish soap on the resin lenses, remove the dust and dirt on the lenses, rinse them under running water, then use toilet paper to absorb the water droplets on the lenses, and finally wipe the water clean with a clean and soft mirror cloth.
3. Avoid scratches on the lenses
At present, the sunglasses on the market are generally made of resin, which has low hardness and is prone to scratches. If you don't pay attention, throw the sunglasses at will, let the resin lenses be placed with the convex side down, and if they come into contact with hard objects and rub against them, the surface of the lenses will be damaged.
Therefore, when not wearing sunglasses, be sure to put them in the glasses case, and keep the lenses facing up when temporarily placed. In addition, resin lenses are not resistant to high temperatures, so they should be avoided from contact with hot water and should not be placed in hot places such as kitchens.
4. Wear sunglasses to distinguish between time and occasion
A big reason why we wear sunglasses is to protect our eyes, but if we don't wear them properly, they can also lead to eye diseases. For example, on cloudy days and indoors, there is no need to wear sunglasses.
Some people wear sunglasses regardless of the occasion, regardless of the intensity of the sun, or even at dusk, evening, and when watching movies and TV, which will inevitably increase the burden of eye adjustment, cause eye muscle tension and fatigue, lead to vision loss, blurred vision, and in severe cases, dizziness and other symptoms.
Only wear sunglasses outdoors when the sun is relatively strong, or when swimming or basking on the beach, and do not wear them at other times or occasions unless there is a special need.
5. Prevent sunglasses syndrome
Sunglasses syndrome refers to long-term wearing of sunglasses, resulting in decreased vision, blurred vision, and in severe cases, symptoms such as headache, dizziness, blurred vision, and inability to see for a long time.
To prevent sunglasses syndrome, it is necessary to choose and use sunglasses correctly. Choose glasses with double pupils that match the shape of your face, and avoid wearing large sunglasses as much as possible.
When you must wear them, try to shorten the time of wearing glasses, and massage them with your fingers along the orbits and sides of the nose 10-20 times after removing them.
Once sunglasses syndrome occurs, you should stop wearing sunglasses immediately, and if the condition is serious, you need to go to the ophthalmology department of the hospital to seek help from a doctor.
PART 04
# Its function is also different #
Knowing the secrets of sunglasses color will allow you to better protect your eyes while adding a sense of style. There are many colors of sunglasses, and the more common ones are brown, gray, green, yellow and red lenses.
Brown:
Brown lenses filter out a large amount of blue light, which can improve visual contrast and clarity, and are suitable for wearing in situations of high air pollution or fog.
Brown lenses reduce brightness while minimizing distortion of object colors, and slightly reduce blue light halos, resulting in clearer images and providing glare protection. Brown lenses block reflected light from smooth, shiny surfaces, allowing people to see the fine details even when wearing sunglasses, making them ideal for drivers.
Gray:
Grey lenses filter almost equal amounts of color in sunlight and can fully absorb infrared and 98% ultraviolet rays. Its biggest advantage is that it does not change the original color of the scenery due to the lens, and it can reduce the light intensity very effectively.
Green:
Like gray lenses, green lenses can effectively absorb infrared and 99% of ultraviolet rays. However, green lenses also block the blue and red in the light, resulting in the color of the scenery sometimes changing after passing through the green lens, and its light blocking effect is slightly lower than that of gray lenses.
Red system:
Red lenses can filter 95% of ultraviolet rays and some visible light with shorter wavelengths, and are recommended for use in changeable weather conditions.
Yellow Lenses:
It absorbs 100% of UV rays and allows infrared and 83% visible light to penetrate the lenses.
The biggest feature of yellow lenses is that they absorb most of the blue light. When sunlight passes through the atmosphere, it is mainly expressed as blue light (which can explain why the sky is blue), and after the yellow lens absorbs blue light, it can make the scenery in nature clearer, so it is often used as a "filter", suitable for the light environment in the early morning, dusk or rainy days.
Laser Lens:
It is suitable for particularly sunny and reflective environments such as beaches, snow or boats.