What's Advantage And Disadvantage Of Photochromic Lens ?
The photochromic lens is a light-sensitive lens that color changes with the intensity of sunlight. People can choose grey, tea, red, blue and other colors. Generally grey is the most recommended color, because grey is a medium color, when people see through lens, color of the object is relatively dark without affecting the original color and it can play a role in shading, more suitable for people working outdoors
Photochromic lenses are very convenient for people outdoors. Outdoors with strong light, lens color will become darker, and it will automatically adjust to a transparent color indoors, avoiding the trouble to wear two pairs of glasses to adjust vision and block ultraviolet rays. For nearsighted people, especially when sunlight is strong, people who wear ordinary glasses can only squinting and cannot look directly at the sun. What’s more, eyes are prone to dryness and fatigue, and the pupils will become smaller for a long time, and the refractive system of eyes is disordered, which has a great impact on vision. Through photochromic lenses, people can get better help in the adjustment of vision, such as under strong light and low light.
But photochromic lenses also have some disadvantages. It will take a certain time for photochromic lenses to change color. Color won’t be changed completely once sunlight changes, so people still need a certain time to adapt. And such lenses are not very suitable for people with deep power, because the higher lens power is, the thicker the edge of the lens will be, so that lenses looks not so good and because middle of lens is too thin, shading effect is also not obvious.
When choosing photochromic lenses, people need to notice two parts:
1. People must check the speed of color changing, usually lens will change color completely within 40 seconds under strong sunlight. After leaving sunlight, lenses color will fade to translucency within two minutes. After the color is completely faded, the surface of the lens is transparent, leaving no color.
2. Check whether color is uniform. When checking under sunlight, people need to pay attention to whether the degree of lenses color is the same, in order to avoid the situation that one lens color is dark and one lens color is light.
