Glass and plastic are the most common materials used in eyeglass lenses. However, polycarbonate lenses are rising in popularity thanks to their durability and lightness. So, what are polycarbonate lenses, and what are the pros and cons of using them in your next pair of glasses? Let’s read on to find out.
Polycarbonate Lenses: The Quick Definition
Polycarbonate lenses are impact-resistant lenses often used in prescription glasses for children and highly active adults.
The history of polycarbonates dates back to 1958 when Bayer and General Electric invented this type of plastic. Before their adoption in prescription glasses, manufacturers first used polycarbonate in fighter planes and other industrial applications, such as astronaut gear.
Polycarbonate glass lenses are a game changer for eyeglass wearers who know the common inconvenience of accidentally breaking their glasses lenses. This durable, yet light, plastic is perfect for eyewear.
How Are Polycarbonate Glass Lenses Made?
Polycarbonate is a thermoplastic composed of carbonate chains. Injection molding is the primary process for making polycarbonate glass lenses. Polycarbonate injection molding is a simple and efficient process that results in robust, highly transparent, and impact-resistant glasses.
The lens production process starts with acquiring the polycarbonate used for making the lenses. Makers must prepare the polycarbonate by drying it to remove any water trapped in the material.
Manufacturers melt polycarbonate at high temperatures and inject it into lens molds at high pressures. Depending on their purpose, the lens molds can be spherical, aspherical, or progressive.
Molten polycarbonate fills the mold and then cools down. Most manufacturers apply various treatments to these lenses before shipping them to medical centers. These treatments include blue light filtering, scratch resistance, and anti-reflective treatment.
Your eye doctor will prescribe the best lenses, and help fit your eyeglasses.
Advantages of Polycarbonate Lenses
What are the advantages of polycarbonate lenses? Polycarbonate glasses offer today’s consumers a variety of benefits. Let’s explore each below.
Eyeglasses need to be transparent to benefit the wearer. Polycarbonate is a highly transparent plastic, and doesn’t impact its natural resiliency, durability, or strength.
Polycarbonate lenses come from shatter-proof plastic that’s strong and resistant, making them ideal for children and people with an active lifestyle. If you still need convincing about their natural resistance to impact, polycarbonate glass lenses have the same material as airplane windows and safety glasses.
Lightweight and Comfortable Design
Polycarbonate lenses are lighter than regular plastic and glass lenses, making them comfortable to wear. The lenses do not add extra weight to the bridge of your nose or constantly slide down when worn. Polycarbonate lenses are also significantly thinner than regular glasses, meaning higher prescriptions can be accommodated without increasing bulk.
Polycarbonate naturally filters out UVA and UVB rays. Unlike glass or plastic eyeglasses, polycarbonate lenses have the natural ability to filter out harmful sun rays without the need for additional treatment. You can wear your prescription polycarbonate glasses in direct sunlight without harming your eyes or using sunglasses.
Disadvantages of Polycarbonate Lenses
What are polycarbonate lenses’ disadvantages? Below are a few disadvantages you may experience while wearing polycarbonate glass lenses.
The upfront cost of polycarbonate glasses is relatively higher than regular glasses. However, their durability and versatility make them a worthy investment long-term.
Not Suitable for High-Power Prescriptions
Polycarbonate lenses are not suited to prescriptions stronger than +/-4.0, such as astigmatism. For such strong prescriptions, polycarbonate glass lenses may cause visual distortions.
Despite being shatter-proof, polycarbonate glasses are not scratch-proof and need a scratch-resistant coating to fully protect them.
Comparison to Other Lens Materials
How do polycarbonate eyeglasses match up to other types of eyeglasses?
Polycarbonate vs. Plastic Lenses
Manufacturers first made plastic eyeglasses in the 1940s from CR-39 (Columbia Resin 39). CR-39 became a popular material for eyeglasses due to its affordability, optical clarity, and durability.
Like polycarbonate lenses, plastic eyeglasses are lightweight and impact resistant. However, they cost less than polycarbonate lenses. Also, they are thicker and have a low index of refraction.
Plastic glasses are more vulnerable to scratching even after applying a scratch-resistant layer. They require additional treatment to give them UV protection capabilities.
Polycarbonate Lenses vs. Trivex Lenses
Trivex lenses are a popular alternative to polycarbonate lenses. PPG first made them for the military before applying them to consumer products like eyeglasses. They are an impact-resistant clear plastic material. Trivex is a worthy replacement for polycarbonate lenses as it offers similar benefits.
Manufacturers make polycarbonate lenses through injection molding, while Trivex lenses come from cast molding. The cast molding process is slower than injection modeling. But, it allows for sharper optics that give Trivex an Abbe value of 45. The Abbe value of polycarbonate glasses is 30.
Trivex is lightweight, strong, durable, and has 100% inherent UVA and UVB protection. Unlike polycarbonate, Trivex is harder to find and more expensive.
The visual clarity and high Abbe value make Trivex glasses better suited for people who need high prescription powers.
Polycarbonate Lenses vs. Glass Lenses
Most glasses have featured glass lenses throughout history. Despite their fragility, they are still a popular material for eyeglasses due to their optical clarity. They have the lowest impact resistance among all eyeglasses.
They are also significantly heavier. Even though glass lenses have become lighter over the decades, they are still heavier than polycarbonate and plastic lenses.
Unlike polycarbonate, glass lenses are naturally scratch resistant. However, they lack the natural UV protection found in polycarbonate lenses. Because of this, glass lenses are not an excellent choice for children or people with an active lifestyle.
Polycarbonate Lenses vs. High-Index Lenses
Prescription glasses refract light in various ways, depending on the underlying vision problem. They achieve the correct refraction based on the curvature of the lens.
High-index lenses suit patients with severe vision issues (a prescription above -5/+3). These lenses are often thicker compared to lenses for lower-index prescriptions.
High-index lenses have an Abbe value of 36, which is higher than that of polycarbonate lenses. They have thicker edges and thinner centers.
Get Polycarbonate Lenses from Art of Optiks
Whether you’ve got a new prescription or need to replace broken glasses, you should consider polycarbonate lenses. These lenses are durable, impact-resistant, and have clear, UV-filtering plastic. They are great for children and active adults alike. If your prescription rarely changes, polycarbonate lenses can give you long-term cost savings.
When it comes to polycarbonate lenses, we are your go-to provider. Contact Art of Optiks today and get customized polycarbonate lenses unique to you.