1. The applicability and principle of photochromic sunglasses
Drivers choose to wear photochromic sunglasses to protect their eyes when driving under the strong sunlight or in snow days, while in the place where the light is soft, the lens turns out to be colorless. In fact, photochromic sunglasses change the color according to the amount of UV rays into gray or brown, and can absorb the harmful UV rays.
2. The functions of photochromic sunglasses
The following are the functions of photochromic lenses:
Photochromic: Photochromic lenses darken on exposure to specific types of light, especially UV radiation. Once the light source is removed the lenses will gradually return to their clear state.
Anti-Reflective: Anti-Reflective (AR) coating improves the transmittance of light, reduces reflection from lenses, and eliminates stray lights.
Anti-Radiation: High-vacuum electron beam evaporation, to prevent electromagnetic radiation and electrostatic damage to the glasses.
UV Protection: UV coating blocks up to 99% of rays up to 400nm protecting the eyes from radiation without interfering with visible light.
Anti-Resistance: Anti-resistant coating prevents scratches on the surfaces of lenses.
Hard Coating: Hard coating forms a permanent bond with the surface of the lens that prevents heavy scratches on the surface of the lens.
3. Filling a prescription of photochromic sunglasses
Photochromic lens could be applied to any kind of glasses at FinestGlasses.com.
Specific information of lens that could apply photochromic function:
a. For single vision glasses, photochromic function could be applied to lens with the index of 1.50, 1.57, 1.61 and 1.67
b. For bifocals glasses, photochromic function could be applied to lens with the index of 1.50 and 1.57
c. For progressive glasses, photochromic function could be applied to lens with the index of 1.50, 1.57, 1.59, 1.61, 1.67, and 1.74
Buy Frame + Free Prescription photochromic lenses (almost same quality as transition lenses) http://www.finestglasses.com/free-photochromic-lens/