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Plastic Vs Polycarbonate Lenses- Which One Is Better?

Plastic Vs Polycarbonate Lenses- Which One Is Better?


Anytime you are in the market for a new pair of eyeglasses, you are going to be provided with different options regarding the lens material. There are a lot of great eyeglass lenses in the market, but before you buy a pair, it is imperative to consider both their pros and cons. The different types of lens material vary in their weight, flexibility, durability, thickness, scratch resistance, etc.

They also have an impact on your vision, comfort, and appearance. This then makes it crucial for you to make the right decision or risk ending up with an ineffective item.

In this article, we are going to be discussing specifically plastic and polycarbonate eyeglasses and the major differences between both lens materials.


Overview of Plastic Lenses.

The first lightweight Plastic eyeglass lens made its debut sometime in 1947. Since then, plastic has become a popular and widely used material for making eyeglass lenses.

This is primarily because of its high optical clarity, low cost, impact-resistant, and durable property. 

Since the introduction and use of Plastic lenses (also known as CR-39), it has sealed its mark as the most preferred choice in the optical industry.

The CR-39 is an acronym for “Columbia Resin 39” and the digit indicates that it is the 39th formula that produced the resulting plastic material. Today, in spite of its drawbacks, CR-39 still remains a popular material for making eyeglass lenses. Now that we have a brief overview of plastic lenses let us consider some of its advantages and disadvantages.


Advantages of Plastic Lenses.

 It is lightweight: Plastic materials are known to be lighter in weight and also strong to a certain extent. The lightweight property of plastic makes it a great eyeglass lens material because it will not be heavy inside a glass frame and permits for an easy fit in any type of glass frame.
    Low cost and affordable: The raw materials for manufacturing plastic are relatively cheap and easy to obtain in desired amounts. These products can also be made into the desired form quickly and inexpensively. This makes a plastic eyeglass lens low cost and affordable. 
      Impressive Optical Quality: The plastic used for optical applications is typically made out of high-quality raw materials refined through advanced procedures and systems. Plastic eyeglass lenses are very transparent that can easily improve vision and increase visual clarity. 
        High Impact Resistant: Plastic lenses are very durable. They do not shatter easily on impact which makes it a great choice for individuals who are active or tend to drop their glasses often.
          Easy to tint: Plastic easily accepts tints faster than other materials. This makes it easy to apply and treat plastic lenses with ultraviolet (UV) protective coating. A Photochromic lens will darken easily following exposure to extreme light and change lighter with insufficient light.


            Disadvantages of Plastic Lenses. 

            Thickness: Plastic lenses are usually thick due to their low Index of refraction compared to other lens material. The high index plastic types are not as thick as regular plastic, but they are best suited for people with higher optical prescriptions. 
              Vulnerable to scratches: The soft nature of plastic surfaces makes it susceptible to scratching from a sharp object and why scratch-resistant coating is applied to form an additional protective layer. But even with the addition of this scratch-resistant coating, plastic lenses are still one of the lens materials that easily gets scratched. 
                Lack of ultraviolet (UV) protection without extra coating: Longwave Ultraviolet light can easily pass through most plastic materials. Generally, ultraviolet light of wavelengths between 350 to 400nm will pass through plastic without an additional layer of UV protective coating. However, UV light of wavelength less than 300nm would be absorbed.


                  Overview of Polycarbonate Lenses. 

                  Polycarbonate lenses were introduced sometime in the 1980s by the Gentex Corporation. This new eyeglass lens material had a high index of refraction, making it to be the lightest and thinnest lens material available then.

                   Polycarbonate lenses rose to critical acclaim due to its durable, and additional properties. It was seen as a lens material with lots of potential for optimal optical success though it did not gain traction due to three main issues: 

                  Quality: The first use of Polycarbonate lenses in eyewear was in safety glasses, particularly for high-risk individuals. Despite its durable and high impact resistance, dispensing opticians and eye specialists were not impressed by the overall quality of the lens. This was basically due to the tiny black carbon specks embedded in the lens surface of polycarbonate lenses at that time. Dispensing opticians and individuals who were used to the clear surfaces of glass and plastic lenses did not appreciate the tiny black particles.
                    Edging Problems: The unique softness of polycarbonate lenses made edging rather difficult. Polishing the edge of a polycarbonate lens using edgers would often result in cracks and breakage on the lens surface. This inconvenience coupled with constant lens failures, low demand, and need for expensive equipment impeded its wide use. 

                      Surfacing Problems: Surfacing is the process of placing a prescription onto a polycarbonate lens and preparing its surface before it is cut for the glass frame. The unique property of polycarbonate lenses meant that surfacing was going to be an issue. It took manufacturers some time to develop surfacing equipment that could be used to surface a polycarbonate lens. Eventually, effective solutions to these obstacles were put forward in addition to the refinement and enhancement of polycarbonate lenses into the high-quality material widely used today. 

                      Polycarbonate lenses are gradually taking over a significant portion of the optical market share once dominated by plastic lenses. This is mainly because of its lighter weight, impact-resistant, thinner and more scratch-resistant properties. Now that we have a brief overview of polycarbonate lenses let us consider some of its advantages and disadvantages.


                      Advantages and Disadvantages of Polycarbonate Lenses.


                      Advantages of Polycarbonate Lenses: 

                      Greater Protection: Polycarbonate lenses do not break or shatter easily into harmful pieces on impact. Their high impact resistance provides greater protection from eye damage or injury due to broken or shattered eyeglass lenses. This makes polycarbonate lenses the most preferred choice for individuals who engage in sporting activities or high-risk jobs. 
                        Lighter-weight: Polycarbonate lenses are lighter than regular plastic or glass, making it suitable for people who have higher prescriptions. These eyeglass lenses are also thinner making it less heavy than standard plastic or glass lenses.

                          Inherent Ultraviolet (UV) protection: Polycarbonate lens surfaces offer inbuilt ultraviolet protection. A significant percent of harmful ultraviolet rays from a variety of sources are blocked by these lenses.


                          Scratches easily: Polycarbonate is a naturally soft material, making it more subject to scratching without adequate protection with a scratching-resistant coating.
                            Distortion on lens edge for higher prescriptions: It may sometimes be difficult to see out the edges of a polycarbonate lens, mainly because of its field of vision and the manner in which the lens bends light.
                              High dispersion: Polycarbonate lenses have a high dispersion due to its low Abbe value of 30, which causes chromatic aberrations.


                                Which is better- plastic or polycarbonate lenses?

                                Here are some few differences between both lenses to determine which one is better:

                                • Plastic lenses are inexpensive and affordable than polycarbonate lenses which are more expensive. 
                                • Polycarbonate lenses are very resistant to tint in contrast to plastic lenses which accepts tints. 
                                • Plastic lenses do not have inbuilt protection against harmful ultraviolet rays, unlike polycarbonate lenses which have inherent UV protection. 
                                • Polycarbonate lenses have higher impact resistance and offer greater protection than plastic lenses.
                                • Polycarbonate lenses are much lighter in weight than plastic lenses. 
                                • Plastic lenses have a higher optical clarity than polycarbonate lenses. 

                                The decision between a plastic or polycarbonate lens should be made based on personal preference, cost, weight, durability, impact, and scratch resistance.

                                 Which one should you pick? 

                                Eventually, the final decision is up to you. Our job is to highlight the various benefits, drawbacks, and differences between both lenses. We will not specifically recommend one over another if it will not be suitable for your visual needs. 

                                You will find blogs out there strongly claiming and confirming plastic as the better option due to its affordability and high optical quality. If you are shopping for a new eyeglass be sure to find out the lens materials available. You can then apply the information you have on both lenses to determine which will suit your needs best.


                                Final Thoughts.

                                It is not necessarily a one size fits all solution when it comes down to eyeglass lens material. What works for one person might not for another. For instance, certain individuals cannot use polycarbonate lenses, because they experience an odd Visual distortion. In this case, choosing a plastic eyeglass lens or high index lens would be much better.

                                If you need any assistance in selecting the right lenses for your eyewear, please contact us now. Our expert team have vast years of working experience in the optical industry and can help guide you through the decision making process. We look forward to hearing from you.


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