Basic skills
Preface
A pair of sunglasses looks very simple, that is, there are two colored glass lenses or plastic lenses in a plastic or metal frame. Is there anything simpler than this? In fact, two glass lenses can make a lot of differences. When you use sunglasses, these differences will have a great impact on you.
Effect
Ultraviolet rays can damage the cornea and retina, and high-quality sunglasses can completely eliminate ultraviolet rays.
When the eye receives too much light, it will naturally shrink the iris. Once the iris shrinks to its limit, people then need to squint. If there is still too much light, such as sunlight reflected by snow, it will damage the retina. High-quality sunglasses can filter up to 97% of the light that enters the eye to avoid injury.
Certain surfaces, such as water, can reflect a lot of light, and the bright spots produced in this way can disturb the line of sight or hide objects. High-quality sunglasses can use polarization technology to completely eliminate such glare, we will introduce polarization technology later.
Certain frequencies of light will blur the line of sight, while other frequencies of light can enhance contrast. Choose the right color for the sunglasses to make it better in the specific environment.
If sunglasses do not provide UV protection, they will expose you to more UV rays. Cheap sunglasses filter out some of the light, causing your iris to open up to receive more light. This will also allow more ultraviolet rays to enter, increasing the damage caused by ultraviolet rays to the retina.
Therefore, there is indeed a difference between various sunglasses. For a specific use environment, choosing suitable and high-quality sunglasses will provide you with the greatest protection.
According to international standards, sunglasses are classified as personal eye protection products. The main function of sunglasses is to block the harsh sunlight. However, international standards subdivide sunglasses into “fashion sunglasses” and “general purpose glasses”. The quality requirements for “fashion sunglasses” in the standard are relatively low. Because “fashion sunglasses” mainly emphasize style, the wearer pays attention to decoration, not protection. In the standard, the quality requirements for “general-purpose mirrors are relatively strict, including requirements for UV protection, as well as index requirements for diopter and prism.
