Non-reflective coating, also referred to as anti-reflective coating, or glare resistant treatment, is a clear magnesium fluoride coating, normally applied to both sides of a lens. On occasion, the non-reflective coating is applied to only one side of the lens at the customer’s request.
The coating limits light reflection by allowing the maximum amount of light to pass through the lens. Non-reflective coating is effective for reducing headlight glare or a halo effect and helps to reduce eyestrain when using a computer. This means a wearer’s eyes will be less tired at the end of a day spent focusing on a computer monitor. Another benefit of the coating is it causes the lenses to appear cosmetically more pleasing by reducing or eliminating reflections.
While non-reflective coating definitely has its benefits, it also comes with some downsides. The non-reflective coating can cause the lens to have a faint green or blue appearance. Lenses with non-reflective coating are more difficult to clean and are known for smudging easily. Something as simple as a person’s eyelashes lightly brushing across the back of the lens can cause a blurry smudge.
Just as with every other industry, when technology improves, so does a product. This is true with non-reflective coating as well. Because of advancements in technology there are different levels of coatings available today to suit everyone’s needs.
The standard level is considered the lowest of the levels and smudges easily and frequently. This is one of the main reasons it is the least expensive. The ultra and premium levels are the highest of the levels and the most costly. They have a reduced frequency of smudging are more scratch resistant than the standard level making them more appealing and effective for the wearer. They reflect less than the standard level and allow the maximum amount of light to pass through a lens.
There is more than one application process for applying non-reflective coating onto the surface of an eyeglass lens. One process is spraying the coating on, and then exposing the lens to high heat for an extended period of time, causing the liquid solution to harden and adhere to the lens.
Another process is a type of vacuum application where the lens is placed inside a large machine and then coated with a liquid. The vacuum process combined with high intense heat results in a hard layer of non-reflective scratch resistant coating adhering to the lens.
A third process of how non-reflective coating is applied to a lens is in the fabrication process at the time the lens is made. The coating is actually built into the material and distributed throughout the lens.
If the non-reflective coating is defective or becomes scratched, the coating can be removed. This will get rid of any discoloration caused by crazing or scratches, making the lens virtually brand new to the wearer.