Eyeglass Lens Materials Guide:
The lens material you pick for your glasses will have a large impact on the optical clarity, weight, durability, and cost of your glasses. Each material has certain advantages and disadvantages, which are important to know in order to make an informed decision while in our office. However, optical terminology can be confusing and overwhelming for many patients, and sometimes, time constraints in the office limit clarifying questions. Below, we list several pros and cons for each material to help you better understand the options available to you when choosing your eyeglass lens material.
Glass Lenses
Glass is the original material used to make corrective lenses. However, they are quickly becoming obsolete due new and better technologies.
Pros:
- Do not require a scratch resistant coating. Glass is naturally scratch resistant.
- Great optical clarity, meaning that there is very little distortion in vision when looking through glass lenses.
Cons:
- Heavy. Generally atleast twice the weight of plastic or polycarbonate lenses.
- Thick. Can be almost 50% thicker than polycarbonate or high index plastic lenses.
- Low impact resistance. Glass is much easier to shatter or chip than other lens materials.
- Does not inherently provide 100% UV protection. Glass requires a special coating to achieve 100% UV protection.
CR-39 (Plastic) Lenses
CR-39, which stands for Columbia Resin #39, is a plastic polymer that has become the most common lens material used today. The lens material accepts tint dye better than any other material, making it great for tinted eyewear. It is also thinner and lighter than glass. CR-39 is the budget-friendly choice for many consumers. However, while more shatter resistant than glass, plastic lenses are still not recommended for active sports as they may still shatter upon impact.
Pros:
- Good optical clarity. There is only slightly more distortion than in glass.
- Lightweight. Generally half the weight of glass lenses.
- Easy to tint.
- Budget-friendly
Cons:
- While thinner than glass, CR-39 plastic lenses are still ~30% thicker than polycarbonate or high index plastic lenses.
- Not scratch resistant. Special scratch resistant coatings are highly recommended.
- Requires a special coating in order to achieve 100% UV protection.
Polycarbonate Lenses:
Polycarbonate is exceptionally strong and shatter resistant. It is one of the strongest and safest materials on the market. For rimless or semi-rimless glasses, a polycarbonate lens will greatly reduce the likelihood of cracks or other damage. It is one of the thinnest and lightest lens materials. This material is highly recommended for any sport/active eyewear due to its high impact resistance.
Pros:
- Excellent impact resistance. Highly recommended for active eyewear.
- Thin. About 25% thinner than plastic.
- Lightweight. About 20% lighter than plastic lenses.
- Inherently blocks 100% of UV rays without any special coating.
Cons:
- With higher prescription powers, peripheral vision may be slightly less clear.
- More lens reflections than glass or plastic lenses. Thus, an anti-reflective coating is highly recommended.
Mid, High, and Ultra High Index Plastic Lenses:
Mid, high, and ultra high index plastic lenses are compressed plastic lenses that are thinner, lighter, and flatter, than many other lens materials. They also provide great optical clarity. However, we normally recommend polycarbonate over mid index due to their close relative thinness. Therefore, we will be focusing this section primarily on high and super high index lenses. High and Ultra high index plastic lenses are best known for their extreme thinness. They are thinner than polycarbonate, and are often reserved for those with a high prescription, or desire the thinnest lens possible. In many cases, they are lighter than other materials, but not always. Despite being thin, the density of the frames can sometimes lead to a heavier lens.
Pros:
- Lightweight. Heavier than polycarbonate but lighter than CR-39 plastic.
- Thin. The higher the index, the thinner the lens.
- Better optical clarity than polycarbonate in the periphery.
Cons:
- Requires scratch resistant coating for durability.
- More lens reflections than glass or plastic lenses. Thus, an anti-reflective coating is highly recommended.
That’s all for this section.
We hope this lens material guide was helpful for you. Thanks for reading!