In recent years, sunglasses are widely used by
Photochromic lenses are great for those that wear rx sunglasses. They have many molecules embedded in them. These molecules are transparent to visible light in the absence of UV light, so the lenses will be light. When there is no UV rays around, the molecules will react and change shape. When this happens, the molecules will absorb some of the visible lights and then darken the lenses. In a word, the lenses color can be changed by the influnce of environment.
When we know photochromic lenses clearly, we can easily make some conclusions about do's and don'ts when sunglasses with photochromic lenses are used in our life.
It is obvious that people have poor eyesight who frequently go into house and go outside can get a pair of photochromic RX sunglasses to solve all of their problems. When they stay indoors, their sunglasses can act as a pair of regular RX eyeglasses that help them see views clearly. The lenses will darken and turn to be a shield for their eyes in the strong sunlight if they go outside. Some porters who do their works and commute to rooms and open air are strongly recommended for a pair of photochromic sunglasses. Besides, it is also suitable for almost all of the outdoor sports such as skiing, climbing, play basketballs and so on.
However, this sunglass also has its limit. It can not be used for driving. As the glasses around car are tinted in dark color, which usually can block many rays automatically, and sunglasses with photochromic lenses can not be functional. When wearers are in the car, the lenses may become darken in the absence of UV rays, which will affect your driving.