Photochromic glasses are eyeglasses fitted with color-changing or color-adjusting lenses, which become colored when exposed to the sun, and become transparent when you come indoors. Photochromic lenses change when you want them to change into sunglasses, and become normal nearsighted or farsighted glasses when you don't need them.
Photochromic lenses are optical lenses that become colored when exposed to the sun and change to normal, clear lenses when they enter the room. They are suitable for people who go in and out a lot, or for people who are sensitive to light.
Photochromic lenses work by adding silver halide particles to the raw material of the lens, which decompose into halogen ions and silver ions under the action of ultraviolet rays of the sun, thus changing color. The stronger the UV rays of the sun, the stronger the chemical reaction and the deeper the discoloration.
Strictly speaking, it can't block blue light. Anti-blue light lenses are made by adding special substances to the film layer of the lens to reflect harmful blue light or special substances to the lens material to absorb blue light, while photochromic lenses do not have these substances, so they can not block blue light. However, most of the photochromic lenses on the market today have special substances added to block blue light so that they can have an anti-blue light effect.