Many people in the world have poor eyesight. According to the World Health Organization, there are around 37 million blind people worldwide and 124 million people with poor eyesight. Every five seconds in the world one adult is blinded, every minute is a child. Each of us has a friend who wears glasses or contact lenses, and maybe you yourself have vision problems.
At such prevalence of such subject as glasses few people were asked by a question "As them do?". In this post I will try to clarify this issue.
To start a little history.
The first glasses, similar to modern, appeared in Italy in the 13th century and were quite an expensive treat. Prior to this, people also corrected eye problems before looking through certain polished crystals.
The glasses developed not only as a device for correcting vision problems, but also as an accessory. From glasses in their usual form there were such things as a monocle or a pince-nez, but at the moment they are unpopular, as they are inferior in convenience to modern frames.
Modern glasses and their manufacture
The frame in modern glasses not only retains the lenses, but is also an element of style. There are an incredible number of types of frames, both in the way of fixing the lenses and in appearance, but the main role of the rim still reliably hold the lenses. Due to the fact that two identical frames can not be found - the lenses that need to be inserted into the frame are made individually.
To start a little history.
Once upon a time, the lenses were hand-cut from the workpiece on a similar or similar machine. The process was long, difficult and not very useful, because the glass dust of health to the master clearly did not add. The development of technology has not bypassed optics.
Nowadays modern devices practically do not require the participation of a master in the process of undercutting the lens. The photo is not the most modern, but trouble-free semiautomatic machine.
This is how the lens looks before it is inserted into the machine. Modern lenses are practically not made of glass, for these purposes, different optical polycarbonates with different coatings are used. In the market there is a great variety of eyeglasses for all requests and wallets. In some cases, the cost of a pair of spectacle lenses can easily exceed $ 1000.
After the lengthening of the lenses they are inserted into the frame and ready glasses are received by the satisfied customer.
If you are interested in the topic of optics "from within" - ask questions in the comments, I will be happy to answer them.