The selection of an eyeglass should never be based only on its design and shape. The main purpose of eyeglasses is to keep your vision crisp and clear and to provide your eyes protection against UV light and other harmful elements.
This makes it important that you choose the lens materials for your sunglasses with extreme care. You need a lens that offers greater impact resistance, excellent optics, attractive aesthetics, UV protection, and a lightweight build. Now, you can find lenses in different materials in the market and in order to choose what is right for you, you need to learn more about these materials and their main features.
In this article, we are going to look at some of the most common lens materials that you can consider for your sunglasses. But before that, let’s take a look at the main properties of lens materials that affect their quality.
Index of Refraction
It is a number that describes a material’s ability to bend the path of light. The more refractive index a lens has, the more it will bend the light and that means you will need less material to make the lens.
To find the refractive index of a lens you just have to divide the speed of light in vacuum by the speed of light in the medium the lens is made from. The eyeglasses that are made from materials with high refractive index are thinner than the ones made from low reflective index materials.
This number was proposed in the 1800s by a German scientist Earnest Abbe and it gives you a measure of the chromatic dispersion of a lens.
This number measures how widely a lens disperses a certain wavelength of light. If the abbe value is less, that lens will show more dispersion and that can lead to aberration. Most modern lens materials for sunglasses come with an abbe number ranging from 30 to 59.
Another important feature that you need to consider when buying a sunglass lens material is its ability to absorb UV radiation. UV makes up about 5% of all solar radiation and long exposure to it can be really bad for your eyes. Most coated clear-glass lenses, dark sunglass lenses, and polycarbonate lenses possess high ultraviolet-absorbing properties.
So, these are the main properties of lens materials that you need to know in order to find the best glasses to wear on any occasion.
Different Lens Materials and Their Advantages
Here is the information about different lens material with its advantages:
Plastic Lenses or CR-39 Lenses
These lenses can block about 80% of UV light and they have refractive index and Abbe values of about 1.498 and 58 respectively. Their low refractive index requires more thickness which means they are typically heavier.
These sunglass lenses have a soft surface making them less scratch and shatter resistant. These lenses are typically thicker than high-index lenses and they have half the weight of glass lenses.
These lenses for sunglasses are mostly known for their thin profile, lightweight build, high UV resistance, and greater Impact resistance.
These lenses have a refractive index and Abbe value of about 1.586 and 30 respectively making these an ideal choice for children, young adults, and anyone with an active lifestyle. These lenses are about 30% thinner than plastic lenses.
High Index Lenses
These lens materials are both thinner and lighter than plastic or glass lenses. These lenses have a refractive index of about 1.6 or higher and their abbe value is about 32 to 36.
High-India lenses are ideal for high-power prescriptions where they can be used to provide clarity as well as cosmetic attractiveness. These sunglass lenses offer high optical quality as well as impact resistance.
These lenses offer you high impact resistance, great optical quality, and minimum distortion or chromatic aberration. Trivex lenses have a refractive index of 1.54 and an abbe value of about 45. These lenses offer a crisper vision owing to the high abbe number.
These lenses, however, can be heavier owing to their low refractive index. This lens meets every high-velocity impact standard. You can easily coat these lenses to enhance their scratch resistance and durability.
Nylon is a transparent material known for being highly UV resistant and lightweight. lenses made from this material offer longevity and durability owing to their high impact and scratch resistance. These lenses come with a refractive index or 1.5-1.7 and an abbe value of about 52 which imparts them higher optical clarity and performance.
These lenses come with anti-reflective coatings which makes them more scratch resistant. These coatings also ensure the lens is able to block out 100% UVA/UVB light while ensuring unmatched optical clarity.
Our latest AIN collection of glasses come with premium quality Nylon lenses with anti-reflective coating making them the best choice for regular use.
- These lenses are about 1 tenth the weight of regular glass lenses making them a very lightweight eyewear option .
- Nylon lenses are thermoset which means you can recycle them.
- The coatings on these lenses make them more scratch proof than Polycarbonate and CR-39 lenses.
- These lenses offer the best optical quality due to their high abbe value .
- These lenses are highly flexible and durable.
So, these are the main lens materials that you need to consider when making your choice. You need a lens that has a higher abbe value and refractive index. However, sometimes it gets hard to find a middle ground between the two. To get a higher abbe value, you need to make the lens a little heavier while lenses with higher refractive index tend to be lighter.
Each of the lens materials discussed above is suitable for prescriptions of different strengths and that is another thing you need to factor in before making your decision.
You can contact us at Swey Collective to explore premium quality sunglasses that offer more durability, comfort, and clarity.