Purchase Guide For Sunglasses
Sunglasses are a kind of vision care products that can prevent human eyes from being damaged by strong sunlight, or special accessories that reflect personal style. People will choose sunglasses according to different needs.
However, some people often experience discomfort after purchase or encounter quality problems when buying sunglasses. Optician experts remind the public to pay attention to the following points when buying sunglasses:
1. First check the quality of the lens to see if the surface of the lens is smooth, whether there are warpages, wear marks, and air bubbles. The warping of the lens will cause the line of sight to deviate, unevenness or traces, air bubbles, and cause dizziness and other discomfort. Also note that the lens should not be too thin, otherwise high temperature deformation will also cause dizziness.
2. Take the sunglasses 45 cm away from your eyes, observe the vertical and horizontal lines around you through the glasses, such as window frames or door frames, and then move the glasses up and down. If the straight line is distorted or oscillating, it means that the lens is deformed and should not be purchased.
3. Sunglasses also has an important index of light transmittance, which is the ratio of the luminous flux through the lens to the incident luminous flux, and is also an important performance index stipulated by a mandatory standard. If light-colored sunglasses are used for shading, the wearer will not be able to obtain the effect of shading. Use sun-shading mirrors for light-colored sunglasses, which will affect the clear vision of the wearer.
4. Put the sunglasses in front of your eyes, observe the distant target through the lens, such as window frame or door frame, etc., and then move the glasses up and down back and forth. The target should not swing or wavy. You can also observe the image of the lamp tube on the surface of the sunglasses lens under a fluorescent lamp. Turn the sunglasses to make the image of the lamp tube appear on different parts of the lens. Some of the polarized sunglasses on the market use resin polarized lenses with a thickness of 0.7mm. Because the lenses are thin, they are prone to deformation during assembly. Special attention should be paid when purchasing.
5. The color of the lens should not be biased, and the color of the surrounding environment should not be distorted. Before wearing sunglasses, observe the red, green, and yellow objects first, then put on the sunglasses and observe the same objects. The color of the two observations should not be color cast, otherwise the ability to identify traffic lights will be reduced. For colored lenses, especially brightly colored sunglasses, attention should be paid to the identification of this item.
