Nowadays, most optical retailers just aren’t using glass to manufacture eyeglasses anymore. Although some people still fancy glass lenses over anything else, the majority of people who wear eyeglasses have turned to more advanced optical technology. There are two main lens materials that are used more than any others these days. They are Polycarbonate and CR39. Aside from being composed of different elements, they also have some differences in terms of feel, vision, durability and price.
CR39 is a type of plastic. Most manufacturers of discount eyeglasses offer their cheapest pairs with CR39 lenses. This is because CR39 is extremely cheap. The process of making them is easy and very affordable for optical companies. Believe it or not, CR39 is actually better optically than Polycarbonate. The difference is incredibly subtle, but it’s there. However, many people choose other lens materials anyway because of the down sides of CR39. Because it is a type of plastic, CR39 is not very durable at all. If the lenses are stressed or bent in any way, or if the eyeglasses are twisted by accident, the chances of the lenses breaking or chipping are not terrible. CR39 also tends to be a bit heavier and thicker than a Polycarbonate lens of the same prescription would be. If you are looking into buying prescription sunglasses, CR39 might actually be a good idea. It tends to tint, and hold tint better than other lens materials. In fact, most non-prescription sunglasses are made with some type of plastic lenses.
Polycarbonate is comparable to an acrylic material, and it has many uses. It has actually been used to make bomb proof shelters. Polycarbonate is incredibly durable. It can practically be bent in half without breaking. Which is why it is the law for kids eyeglasses to be made only with Polycarbonate. Compared to other lens materials, it is also thinner and lighter. For the most part, wearing a pair of eyeglasses with Polycarbonate lenses does not weigh your face and head down, or give you headaches. Another great quality it possesses is scratch resistance. No matter what lens material you have, scratches are always possible. However, Polycarbonate is known to be very resistant to obtaining a permanent scratch.
When thinking of what lens materials to buy, keep these facts in mind. Weigh the pros and cons of all the things you find, and make an educated decision. Eyeglasses are all about preference, and you should go as into detail as possible when shopping for them.