The history of plastic being used in optical industry can be dated back to near a hundred years ago. And now, this material becomes one of the most important and widely used substances to make eyeglasses. Especially, this material becomes much more popular than ever before, when sunglasses are used as the most important decorating articles among wearers from all walks of life. It is true that plastic sunglasses are currently some of the commonest sunglass wear in the market. However, there are still some merits and demerits on these sunglasses. Here are some of them.
Plastic sun glasses are lightweight and can bring wearers great convenience. Before the emergence of plastic, sunglass products are made from very traditional materials that are usually very heavy to have on. Therefore, people with these sun eye wear are always bothered and troubled by the inconvenience caused by heaviness. Luckily, when plastic is used, sunglasses are no longer as heavy as they used to be. They are lightweight and can offer great comfort to people. One good example is people with strong prescription. In the past, people will find that their eyeglasses lenses become thicker on and on as their prescription get stronger and stronger- thicker lenses can make sure lights are well reflected. However, many people can not stand such situation. And this problem is not solved until the emergence of high index lenses. These plastic lenses play the same role as those thick glass lenses, but as thin as regular lenses. And the result is wearers are no longer needed to carry thick bothering eyeglasses all day long.
Plastic sunglasses wear can now also be durable if processed in special techniques. Plastic are much bendable than other materials, like wood, metal, etc. In particular, the emergence of memory plastic has made plastic sun wear some of the most durable products in the field. These sun eye wear can not only stand very strong impact, but also will rebound their previous shapes after bending.
However, because plastic sunglasses are made from polymers and other organic materials, they should be maintained in place where PH is no more than 8. When PH is over eight, the environment is alkalic, where some chemical reaction will occur and the plastic sun glasses will be damaged. Therefore, these sunglass wear must be maintained in circumstance where the PH is 7 or so.