choosing to take sunglasses use

The lens is the most important part, sunglasses. There are several different types of lens. Lens can be material in different colors,, and coating. More high-quality lenses are generally preferred, because the cheapest lens distorts the image. Image distortion can cause eye strain. After a long time, which may lead to long-term headache, nausea, dizziness.
Lens type of material is glass, CR-39, polycarbonate plastic, acrylic plastic. These materials are of the highest quality, attention to visual quality just like people advice and materials are glass. Also the scratch resistant glass lenses, but they are very easy to smash hit. The other three types of materials are all plastic and impact resistance. Acrylic plastic must be special treatment, using it to protect the wearer from UV damage.
The lens is also different shades. Darker shades will absorb a significant amount of light higher than lighter shades. A different shade of color also serve different purposes. Yellow or orange hue will reduce the blue light, which is the main component of dazzling. Therefore, these sunglasses are popular sports, glare quantity has higher (boating, fishing, skiing). Good driving brown color, gray is a very good golf, running, or riding a bike. Different colors have different abilities, in order to reduce glare. The best advice is to consider when choosing to take sunglasses use.
Finally, sunglasses have all kinds of paint. Ultraviolet protective coating must be sunglasses. Harmful UV sun will seriously damage the eyes. Some sunglasses may have a dark hue, but special coating is not to protect the skin from ultraviolet radiation damage. Other coating can also help improve scratch sunglasses. In addition, mirrors or lenses flash coating, and antireflection coating lens can greatly reduce the absorption of light, and reduce glare or "halo" effect. Once again, the coating should be selected depends on the intended use of sunglasses.
Sunglasses are under different conditions are essential.