What are Transition Lenses?
Definition of Transition Lenses
Transition lenses are the same thing as Photochromatic lenses and have the ability to darken automatically when exposed to UV rays (Ultra-Violet). The degree of darkness (tint) is dependent upon the intensity of light. If the light is very strong, transition lenses will almost become opaque, if the light is not as intense, the lenses will become more clear (the tint disappears).
Basically, the lenses get darker when it is sunny, and gets clearer when its darker. Transition lenses have been implemented in prescription eye glasses as an added benefit to the consumer. They are normal glasses when you are indoors, and sunglasses at night. This is great, because now you don't have to buy two pairs of prescription glasses.
Get Affordable Transition Prescription Glasses Online
Transition prescription glasses can become very costly, and can make a nice dent in your pocket. I found that purchasing prescription eye-wear online is a great solution to this problem. After buying my glasses from local stores for years, I decided to buy some online. What a great idea that was.
Instead of spending hundreds on just one pair, you can get 3 or 4 for the price of one. I have been buying my prescription glasses with transition lenses from www.GreatEyeGlasses.com. Check them out, you won't be disappointed.
The Science Behind Transition Lenses
A scientific element, Micro-crystalline silver halides (usually silver chloride), is the substance that is responsible for the photo-chromatic property of the lenses. This substance is embedded into the glass version of lenses to make them photo-chromatic. Transition lenses contains millions of silver halides crystals, and when exposed to sunlight the UV rays transform the crystals into light absorbing particles. When these particles absorb light, the lenses darken and the amount of light passing through the lens is reduced. When the lenses are removed from the sun's exposure exposure and the stimulating UV radiation is not present anymore, the crystals then return to their original orientation and the lenses become clear.
On the other hand, unlike glass lenses, the transitional property in plastic lenses depends upon organic photo-chromatic molecules for their reversible darkening. The main reason that these lenses darken in the sunlight, and not in indoors, is that there is not any ultraviolet rays indoors. The Photo-chromatic lenses come back to their original color due to thermal process. Because of this reason, some plastic lenses do not work very well in hot temperatures.