Nowadays, we buy eyeglasses according to their frame material, lens material as well as their brands and styles, as there is huge variety of glasses in the market, and when in some local stores, we may often hear the retail staff refer plastic eyeglasses and metal eyeglasses, actually, In most cases, they mean the material of the eye wears which they are introducing to you, such as “plastic eyeglasses” refers to eyeglasses that have plastic frame material. And today's people are more inclined to compare these two kinds of frames, though these two frame materials do have some different features, they both have their respective pros and cons, such as metal ones are more durable and the temples can be made much thinner than plastic one, but some people's skin may be sensitive to such material, while plastic ones solve this problem perfectly and they are much lighter, the drawback is their poorer durability.
Actually, plastic eyeglasses can also be used to describe eyeglasses made of plastic lenses. Before the 20th century, which is a time people all needed to wear heavy and low refractive index glass lenses, and you may heard that a pair of these lenses can exert considerable weight on the wearer's nose, especially for those who have a strong prescription, there were no high index lenses as today, so, the lenses are becoming exaggerated heavy and thick, that's the reason why we call them “coke-bottle” lenses, so, plastic eyeglasses lenses were a great invention. And what's more, those glass lenses are quite fragile, in a serious case, the eyes may get injured when the lenses are hit by a punch, so, how many pairs of eyeglasses does a basket player who suffers from myopia need to buy in one year? So, we can get this conclusion, it was these disadvantages of eyeglasses lenses that forced innovators to develop an alternative.
In general, plastic lenses are much lighter, safer, and more durable than old days' glasses lenses, that's to say, plastic lenses perfectly solve the problem of being lightweight and shatter-resistant. Wearers can enjoy comfort and safety from these plastic eyeglasses, and it is estimated that approximately 73% of the world's eyeglasses lenses are made of plastic. After a couple of decades' progression, more complex plastic lenses are innovated, which have more additional advantages compared with traditional plastic, a typical example is CR-39 lenses, which have been the standard material for eyeglasses lenses for many years. They are not only light but also have better UV light protection, and are less likely to shatter, and they can still be treated with advanced coatings such as scratch-resistant coating!
