I know all you would be thinking what else could a glass do apart from making you look good, helping your eyesight,and also help to reducing the sun rays!!!.
Well I'm hear to informed you that this eyeglass has the ability to change from a clear glass to a tinted glass depending on the atmospherical conditions I.e indoors and outdoors....
Yes yes yes, i know you guys would be saying How can my glasses change from transparent, when I'm inside, to dark when I go outdoors?
They are called the transition glasses which could be changed in color. When you are out, the lenses will be changed in the dark color. When you are in the room, your lenses will be transparent. This kind of glasses will protect your eyes from the ultraviolet rays in the strong sun light. It could also make you see clearly with prescription when you are short sighted. It is really the good pair of glasses, but this is not the beginning if this wonderful piece of tech....
Sunglasses or prescription eyeglasses that darken when exposed to the sun were first developed by Corning in the late 1960s and popularized by Transitions in the 1990s.
In fact, because of the extreme popularity of the Transitions brand, these lenses are usually referred to as transition lenses. The correct term for these glasses is photochromic or photochromatic, which refers to a specific chemical reaction the lenses have to ultraviolet (UV) radiation.
Photochromic lenses have millions of molecules of substances such as silver chloride or silver halide embedded in them. The molecules are transparent to visible light in the absence of UV light, which is normal for artificial lighting. But when exposed to UV rays, as in direct sunlight, the molecules undergo a chemical process that causes them to change shape. The new molecular structure absorbs portions of the visible light, causing the lenses to darken. The number of molecules that change shape varies with the intensity of the UV rays.
When you go indoors and out of the UV light, a different chemical reaction takes place. The absence of the UV radiation causes the molecules to "snap back" to their original shape, resulting in the loss of their light absorbing properties. In both directions, the entire process happens very rapidly.
The advantage and disadvantage of Photochromic lens
ADVANTAGE
(1). If you have both vision problem which requires you to wear a pair of glasses and you are also in need of a pair of sunglasses to protect yourself from ultraviolet, you can have photochromis lens as it has both functions of sunglasses and normal glasses.
(2). This eyeglass is very important in cycling sports which can help too eradicate sudden blackout when they enter places like caves and after coming out the experience this sudden blindness which can lead to accident but with the help of things photochromic glasses accident can now be greatly with used in sports because it would automatically reduce the tendency of accidents by changing its colour from clear too dark.
DISADVANTAGE
The colour doesn't change quick enough, and because of this delay some things might occur within the short Period of time because in emergency situation this glass can deprive the wearing of a clear vision that has the possibility of amounting to injuries.
Regardless of the disadvantage I really think that it's an amazing pieces of technology that can help in tourism , entertainment, parties and even researchers who are on their system all day long typing, watching videos e.tc. for more information this glass is now available on alibaba.com. And maybe it can also be found on Amazon.com.
I hope this post was of great help and information to you all , please if want to see more of this you can follow me 
You can also be of great help to others by resteeming this post so that you can help others get in touch with all the amazing and exciting thrills on technology.
Thanks once again for patiently reading through I hope to see more of you!!!!!!.