When you have an eye exam and receive a prescription to have glasses made, you'll be able to select the material that the lenses are made from. Two common choices are CR-39 and polycarbonate. They're both very durable types of plastic that make excellent lenses for glasses, but there are some significant differences between them. To find out if CR-39 or polycarbonate would be the best choice for your new glasses, read on to find out how they compare.
Thickness
One of the biggest reasons that people choose polycarbonate lenses is that they're able to correct your vision with a thinner lens when compared to CR-39. Eyeglasses help you see better by bending light before it reaches your eye. Polycarbonate has a higher refraction index than CR-39, which means that it's able to bend light more rapidly as it passes through the lens. They can also be made thinner.
If you have a high prescription and require significant correction in order to see well, then polycarbonate may be a better choice — CR-39 lenses for people with a high prescription will be very thick, and this can make the lenses look bulky.
Impact Resistance
Another important difference between polycarbonate and CR-39 is that polycarbonate has much higher impact resistance. Polycarbonate lenses are much less likely to break if they're hit by a flying object. If you play sports like tennis or baseball or if you work in a job where you need eye protection, then polycarbonate lenses are a good choice.
Frame Style
One disadvantage of CR-39 lenses is that they tend to split apart when you drill them. Frameless and semi-frameless glasses usually require drilling through the lens in order to mount the lenses onto the frame. Unfortunately, this makes CR-39 lenses unsuitable for these frame styles. If you want your next pair of glasses to be frameless or semi-frameless, you'll need to choose polycarbonate lenses.
Image Quality
One advantage of CR-39 lenses is that they have better image quality than polycarbonate lenses. Polycarbonate lenses are slightly more opaque, and they scatter light more as it passes through the lens. This can result in your vision being slightly blurred when you're wearing polycarbonate lenses. CR-39 lenses, on the other hand, have higher image quality because they barely distort light at all as it passes through the lens.
Cost
A major downside of polycarbonate lenses is that they're quite expensive, whereas CR-39 lenses are the least expensive type of lenses you can buy — they're commonly used in budget eyeglasses. If price is a concern, then CR-39 lenses will be a more suitable option.
Overall, the main reasons to choose CR-39 lenses are their superior image quality and significantly lower price, and they'll be an excellent fit for most people. If you live an active lifestyle and need impact-resistant lenses or if you have a high prescription that would result in CR-39 lenses being too thick, however, then polycarbonate lenses are worth the extra price. You're also limited to polycarbonate if you want frameless or semi-frameless glasses. If you need help deciding, visit an eyeglass store and see if they have sample glasses with both types of lenses — this will allow you to see the difference in image quality and thickness yourself, which can help you make your decision.
Reach out to a service such as Cohen's Fashion Optical to learn more.
Share