Eyeglass Lens Coatings 101 – The Basics

in-house AR

Eye care and optical technology are more advanced than ever and this includes a large number of lens options available to patients. Lens choice is important for aesthetics, comfort, and effectiveness. Beyond choosing a lens, the type of coating used can enhance both the performance and appearance of lenses. Here, we breakdown the types of lens coatings and their use.

Mirror coating

Mirror coating is a cosmetic lens coating often used for sunglasses. It’s available in many colors including silver, gold, and blue. Mirror coating keeps the eyes completely hidden from view.

Anti-fog coating

While not a commonly used lens coating for regular eyeglasses, anti-fog coating can be beneficial in cold climates and cold weather. When going from the cold outdoors to the warmer indoors can cause glasses to fog up. Athletes can have issues with fogging caused by sweating. An anti-fog coating can greatly reduce the annoying moisture on lenses.

Multiple companies offer anti-fog options. Fog Free by Opticote is a factory applied coating that can be applied to plastic, polycarbonate and other eyeglass lenses, including high-index lenses and Transitions photochromic lenses. Essilor offers Optifog lenses that require some maintenance. The anti-fog property is activated by the Optifog Activator droplets, which need to be reapplied weekly.

UV coating

UV coating is used in sunglasses and high-index plastic to prevent the wearer from experiencing the damaging effects of UV rays. Over time, exposure to UV radiation can impact eye health and is known to contribute to cataracts, macular degeneration, and retinal damage. The majority of high-index plastic lenses and most sunglasses have 100 percent UV protection built-in to block all harmful UVA and UVB rays. The exception is CR-39 plastic lenses, which require an additional UV coating to be effective.

Photochromic treatment

Also providing UV protection are Photochromic lenses, also known as the brand name Transitions. Though not a coating, photochromic lenses are available for nearly all lenses and designs. These lenses automatically darken in the sun and lighten indoors, eliminating the need for the wearer to have a separate pair of prescription sunglasses.

Scratch-resistant coating

Because many customers wear their prescription eyeglasses every day, scratches are a common issue. Unfortunately, nothing can completely eliminate scratches, but an anti-scratch coating can greatly reduce scratches, improving vision and longevity of lenses. A clear coating is applied to both the front and back of the lenses, making them much more durable. Lenses for kids especially benefit from anti-scratch coating.

Anti-reflective coating

Anti-reflective coating addresses and corrects common issues that clients experience with glare. It consists of a microscopically thin layer of coating applied to the front and back surfaces of lenses. An AR coating eliminates glare caused by light reflecting from the lenses, improving better vision for reading, computer use, and night driving. Additionally, it makes the lenses appear invisible, so other people can easily see the wearer’s eyes. 

AR coating is recommended for all lenses but is especially useful in certain cases. Polycarbonate and high-index lenses reflect more light than regular glass or plastic lenses. Andaspheric lenses have flatter curves than regular lenses which cause reflections. AR coating is also recommended for photochromic lenses to reduce glare in bright sunlight and improve vision for night driving.

As an important addition to most prescription lenses, Allentown Optical offers in-house AR in addition to our full range of optical services.