The oldest is crystal glasses or transparent minerals making circular monolithic mirror. However, when the car suddenly approached by a dark, when the daylight, wearing black Cheap Oakleys Frogskins Sunglasses Outlet glasses have become the burden. In the sun, it was a pair of black sunglasses; thick black glass lenses block the dazzling light. In the soft light of the room, it also becomes the same as ordinary glasses, transparent and colorless. This special glass is called photo chromic glass. It is in the manufacturing process, the pre- light-sensitive material braced, and a small amount of copper oxide catalyst. Glasses from no color becomes light gray, dark brown, and then change back from the dark tone through glasses are silver halide becomes magic.
Color glasses in glass, the exposure of the photographic film and there is a similar change in the imaging process. The silver halide to light decompose into many black silver particles uniformly distributed in the glass, the glass lens so dim, blocking passage of light, which is the black glasses. But, the situation is not the same on the photographic film, the silver halide decomposition of silver atoms and halogen atoms, still tightly put together. When back a little darker place, in the promotion of copper oxide catalyst of silver and halogen compounds re- produce silver halide, glass lenses and become transparent. Resident of silver halide in the glass, the decomposition reactions and compounds infinitely repeated manner. Photographic film and photographic paper can only be used once, but you can always use color glasses down.
With color glasses can not only change the intensity of light dimmed out, but also absorb harmful ultraviolet rays to the human eye, indeed Tiffany and Co Heart Necklace Jewelry Outlet glasses in the top grade. If the windows are replaced photo chromic glass, sunny, sun room to shoot less; cloudy day or in the morning, at dusk, outdoor light is not blocked, still with bright interior. This seems to put fan windows automatic shades. In some upscale hotel, restaurant has been the placement of discolored glass. This photo chromic glass cab and tour the car window mounted in direct sunlight, even the color glasses do not have to wear, the car has remained soft light, avoid bright sunlight and exposure.
Both ordinary glasses contact lenses for vision correction function, but also lifted the glasses for the inconvenience, so wear contact lenses have become a today fashion. Schoolchildren are in strong growth period, not yet shaped the visual axis of the eye, if premature or longer continuous wear contact lenses, corneal hypoxia and physiological easy to produce side effects such as metabolic disorders; lens cleaning and disinfection lax, it will continue infections; lenses if paths are incompatible with the cornea, can also cause corneal abrasion, epithelial shedding, can cause severe corneal ulceration or perforation. Accordingly, if there is no special need students, or to wear glasses is appropriate. Hands often with a large number of patients with flu germs, they are easy to take, into the eyes when wearing contact lenses. In addition, flu is often accompanied by a slight inflammation of the retina, wearing contact Tiffany and Co Bracelet Jewelry Outlet lenses cause inflammation. Many colds, cough, and pain medicines contain ingredients suppress tears. Contact lenses will reduce the amount of tear secretion is too dry; reduce transparency, thereby affecting vision.