What's The Difference Between Polycarbonate And Plastic Lenses?
You may have heard about plastic and polycarbonate lenses, but do you know the difference between them? Well, it's all about material composition, durability, and impact resistance! This article elucidates what sets these two popular lens types apart. So, get ready to broaden your knowledge in order to make a more informed decision for your next pair of glasses. Whether you're at 50 Dollar Eye Guy or browsing online, rest assured Dr. Joseph Tegenkamp's commitment is to provide high-quality, personalized care, including a comprehensive eye exam and a wide selection of fashionable eyewear to everyone in Pensacola.
Understanding Polycarbonate Lenses
Definition of Polycarbonate Lenses
Polycarbonate lenses are a type of eyeglass lens made from a thermoplastic polymer, known for its superior impact resistance, lightweight nature, and UV protection characteristics. They were initially conceived for aerospace applications but gradually found their way into various other industries, including eyewear. Today, you find them in many uses, notably for prescription eyeglasses and sunglasses due to their robust safety profile.
Process of Making Polycarbonate Lenses
The process of making polycarbonate lenses is rather intricate. It starts with small polycarbonate granules, which are heated until they melt into a liquid form. The liquid is then injected into lens molds, shaping the lens. Once the liquid cools and hardens, it's removed from the mold as a lens blank. Then comes the refinement: the lens blank is cut and ground to match the prescription specifications. After shaping the lens, protective coatings are applied, which typically include scratch-resistant and anti-reflective coatings.
Common Uses of Polycarbonate Lenses
Polycarbonate lenses are prized for their impact resistance and lightweight nature, making them popular for those leading an active lifestyle or participate in sports. Their inherent UV protection also makes them an excellent choice for children's eyewear and sunglasses. Anywhere safety glasses are needed, such as in industrial applications or shooting ranges, you will often find polycarbonate lenses preferred.
Understanding Plastic Lenses
Definition of Plastic Lenses
When we speak of 'plastic' lenses in the eyewear industry, we're typically discussing CR-39 plastic lenses. Developed by Columbia Resins (hence 'CR'), the '39' signifies the 39th formula out of many attempted to create a lightweight, affordable, and optically clear material. Today, CR-39 plastic remains a popular choice for eyeglass lenses due to its optical clarity and cost-effectiveness.
Process of Making Plastic Lenses
Like polycarbonate, plastic lens creation begins with small granules. But instead of a thermoplastic polymer, the granules are a type of monomer that's heated until it undergoes polymerization, transforming into a solid. This is then injected into a mold, cooled, and hardened. After this, much like the polycarbonate process, the lens blank is milled and ground to match the wearer's prescription, followed by optional and protective coatings application.
Common Uses of Plastic Lenses
Plastic lenses have long been the industry standard for prescription glasses due to their optical clarity, affordable nature, and comfort in wearing. While they're not as strong or as lightweight as polycarbonate lenses, they offer an excellent option for anyone not in need of impact-resistant or UV-protective glasses, such as for reading or computer usage.
Comparing Material Composition
Chemical Composition of Polycarbonate Lenses
Polycarbonate lenses are made from a thermoplastic polymer consisting of carbonate groups within long molecular chains. This construction allows them to absorb large amounts of energy, making them highly resistant to impact.
Chemical Composition of Plastic Lenses
Plastic lenses, specifically CR-39, are derived from a monomer allyl diglycol carbonate. When polymerized, it transforms into a lightweight, clear plastic that can be easily shaped into lenses.
Transparency and Clarity
Clarity in Polycarbonate Lenses
Polycarbonate lenses offer a good level of clarity. However, they have a lower refractive index - meaning they can bend light more - leading to slight distortions at the lens periphery. For most, this isn't noticeable, but for higher prescriptions, it could be of concern.
Clarity in Plastic Lenses
Plastic lenses, particularly CR-39, are praised for their optical clarity. They present no inherent distortions or aberrations, delivering a clear, sharp image to the wearer.
Weight and Comfort
Weight of Polycarbonate lenses
Polycarbonate lenses are notably lighter than regular plastic lenses. Their lightweight nature contributes to their comfort, making them ideal for larger frames or higher prescriptions where added weight may become noticeable.
Comfort of Wearing Polycarbonate Lenses
The weight directly influences the comfort of wearing polycarbonate lenses - the lighter weight translates to little pressure on the nose and ears, improving overall comfort.
Weight of Plastic Lenses
Plastic lenses, while heavier than polycarbonate, remain comfortable for many. However, should the prescription require thicker lenses or for larger frames, the increase in weight might become noticeable.
Comfort of Wearing Plastic Lenses
Despite the increased weight, plastic lenses provide comfort for most users. However, for prolonged wear or high prescriptions, you may find polycarbonate lenses indeed more comfortable.
Durability and Scratch Resistance
Durability of Polycarbonate Lenses
Polycarbonate lenses are highly durable due to their inherent impact-resistance. They're an ideal choice if your work or lifestyle involves potential lens impacts.
Scratch Resistance of Polycarbonate Lenses
While durable, polycarbonate lenses are more prone to scratches than plastic lenses unless a scratch-resistant coating is applied.
Durability of Plastic Lenses
While not as strong as polycarbonate lenses, plastic lenses, specifically CR-39 lenses, provide moderate impact resistance suitable for everyday wear.
Scratch Resistance of Plastic Lenses
Plastic lenses have a higher natural resistance to scratches than polycarbonate lenses, but a scratch-resistant coating is still often beneficial.
Protection Against UV Light
UV Protection Offered by Polycarbonate Lenses
Polycarbonate lenses naturally block almost 100% of UV radiation without any additional coatings, making them an excellent choice for outdoor use or children's eyewear.
UV Protection Offered by Plastic Lenses
Plastic lenses don't inherently block UV rays to the same extent as polycarbonate lenses. Often, a special coating must be added to provide full UV protection.
Cost Comparison
Cost of Polycarbonate Lenses
Polycarbonate lenses usually cost more than plastic lenses but often provide value for the added expense with their higher durability, UV protection, and comfort.
Cost of Plastic Lenses
Plastic lenses, especially CR-39 lenses, are often less expensive than polycarbonate and provide excellent visual clarity and scratch resistance for a lower price.
Prescriptions Suited for Both Lenses
Types of Prescriptions Ideal for Polycarbonate Lenses
Polycarbonate lenses are suited for higher prescription powers due to their thin and lightweight nature. They're also ideal for kids' glasses, safety glasses, or anyone leading a highly active life.
Types of Prescriptions Ideal for Plastic Lenses
Plastic lenses are great for low to moderate prescriptions. If you're looking for basic prescription glasses for reading, work, or everyday wear, plastic lenses can be an excellent, cost-effective choice.
Conclusion: Which Lens is Right For You?
Factors to Consider When Choosing Lens Material
When deciding between polycarbonate and plastic lenses, you should consider several factors. Your prescription level, lifestyle, and budget all play essential roles. If you lead an active lifestyle or require high-prescription lenses, polycarbonate could be a wise choice. But if you're in need of an affordable lens option with excellent clarity for everyday use, plastic lenses might better suit you.
Expert Advice from 50 Dollar Eye Guy
Dr. Joseph Tegenkamp and his team at 50 Dollar Eye Guy are committed to providing exceptional customer service and personalized care to their patients. They can provide expert advice, helping you make the best choice for your eyewear material based on your unique situation and needs.
How to Make an Appointment With Dr. Joseph Tegenkamp
Making an appointment with Dr. Joseph Tegenkamp could not be easier. You can call their dedicated hotlines at their two locations in Pensacola, FL, at 850-434-6387 or visit their website at www.50dollareyeguy.com to schedule your visit.
Choosing the right lenses for your needs may be a bit involved, but it's worth the effort to achieve optimal comfort and vision. To ensure you make the most informed choice, it's best to consult with a professional like Dr. Tegenkamp and his friendly, professional team. They are passionate about providing high-quality eyecare and will ensure your chosen lens match your lifestyle and prescription.
