Materials and coatings of sunglass lenses

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Materials and coatings of sunglass lensesCurrently, there is a wide variety of materials for sunglass lenses. Thanks to the advancements in the lens technology, different people can now choose lenses that cater individual needs. In general, sunglass lenses are made of either plastic or glass. Plastic lenses are lightweight and come in different tints. Plastic sunglass lenses can block 80% of UV rays and thus provide good protection from sunlight. While offering excellent optical quality, glass lenses are more susceptible to scratches.

High index lenses

High index lenses are made of the material of high index plastic. This kind of lenses can block out 100% harmful UV rays in the sunlight. In regular, high index lenses are applied with reflective coating. This is because the high index feature also increases lens reflection on the surface. Due to the valuable optical feature of this material, high-index lenses are thinner and thinner than regular plastic lenses. Typically, lenses made of a high-index plastic can be 50% thinner than traditional plastic lenses. Patients with a severe refractive error are perfect target users.

Polycarbonate lenses

Polycarbonate lenses are one of the most common types of sunglass lenses. Besides features such as lightweight and shatter-resistance, polycarbonate lenses provide natural 100% UV protection. These lenses are perfect for active adults and children. Sunglasses using polycarbonate lenses can offer incomparable eye protection and UV protection.

Photochromic lenses

Photochromic lenses can provide appropriate lens darkness according to the surrounding environment. This type of lens always flatters people who need to frequently alternate between indoor and outdoor environments. Without the availability of photochromic glasses, vision impaired patients need to remove sunglasses and change to prescription eyeglasses when they move indoors, or vice versa.

Polarized lenses

Polarized lenses are specially designed for outdoor wear. These lenses can greatly reduce glare by blocking light reflection on a flat surface. Regular participants of outdoor activities including driving, golfing and skiing can significantly benefit from polarized lenses. With the help of polarized sunglasses, the wearers will nearly be free from annoying glare.

Aspheric lenses

Aspheric lenses are particularly suitable for people with a heavy prescription. With an evenly distributed thickness, this type of lenses will not bring an unwanted look because of excessively thick lenses. These lenses have different curves and are able to reduce or eliminate spherical aberrations. And they also help reduce the distortion of the wearer’s eyes.

Scratch-resistant coating

In addition to different lens materials, there are still types of coatings. In order to avoid scratches, sunglass lenses can be treated with a scratch resistant coating (SRC), which is usually included in polycarbonate and high index lenses by default. This lens coating is especially helpful for mischievous kids who may frequently drop the glasses.

Anti-reflective coating

Another common coating is anti-reflective coating (ARC), which is applied in some lenses in order to reduce reflective rays. While eliminating unwanted glare during outdoor activities, lenses with this type of coating are more likely to scratch. Actually, these two types of coatings are mutually exclusive, which means one specific lens can not have both of them.

Lens tints

Lens tint is another common issue. With various tint options, sunglass wearers can choose their favorite color in order to get distinctive looking. However, only plastic lenses can effectively and uniformly absorb tints. In contrast to high index lenses, polycarbonate lenses are harder to tint.