Your Guide to the Different Lens Coatings

You may have heard your eyecare professional or others mention different coatings that can be put on glasses or sunglasses. But what are these different available lens coatings, and what can they do for you?

Your Guide to the Different Lens Coatings Optometrist
Table of Contents

Anti-Reflective Coatings

Anti-reflective coatings, also referred to “AR coating” or “anti-glare coating”, reduces eye strain, allows for clearer vision, and, especially on sunglasses, further reduces the amount of UV rays that reach your eyes.

This is accomplished through the coating practically eliminating all reflections from both the front and back of the lenses. It’s easiest to understand this, and some of the benefits, by looking at the numbers. Standard plastic lenses reflect approximately eight percent of light that hits them, which means that only the remaining 92 reaches your eyes for you to see. High-index lenses reflect even more light, so for those lenses, anti-reflective coating is even more beneficial, especially in low light conditions. One major example is night driving, where, between the low light and the glare from oncoming traffic, it can be hard to see. Glasses with anti-reflective coating can therefore make your nighttime driving both safer, and less stressful.

Other benefits of adding anti-reflective coatings to your lenses can include making the lenses of normal glasses practically invisible, which can help draw attention to your eyes and make it easier to maintain eye contact with people. AR coated glasses also provide greater comfort during computer use, and when applied to photochromic lenses, enhances their quality and comfort without impacting their sun-reactive capability.

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Anti-Reflective Options

There are a few specific types of anti-reflective coatings that your optician might recommend, based in part on your lifestyle. For those who spend most of their time on computers or utilizing other devices with screens, an AR coating that filters out blue light might be the most helpful.

Scratch Proof and Scratch Resistant Lens Coatings

Scratch Proof and Scratch Resistant Lens Coatings

Protection for Your Eyewear

While anti-reflective coating is applied to give your eyes additional protection, scratch proofing is there to ensure that those helpful glasses have some protection of their own. Everyone drops their glasses at one point or another, and we’ve all had that annoying realization that one of our lenses just took a scratch that’s not going to come out. Especially for those who invest more money in higher quality glasses or sunglasses, simple measures to ensure that you can keep using them for an extended period of time is a wise investment.

Scratch Proof vs Scratch Resistant

While each of these descriptors seemingly make very different promises, in practice they are used almost synonymously. It’s impossible to create lenses that are literally immune to suffering scratches. At least for now. Products advertised as scratch proof do tend to be more durable than those advertised as scratch resistant, however.

 Scratch protection is accomplished either by reinforcing the material itself, or by adding a coating to protect it from damage. The latter method is what is primarily used for protecting eyeglass lenses.

The protective coatings, while made out of incredibly strong material, are very thin and designed to not impair the vision of the person wearing the reinforced lenses. (Other devices featuring lenses or screens, such as cameras and computers, also tend to feature scratch resistant coatings.

There are many ways in which eyeglass lenses can become scratched, so if you want your eyewear to last (and especially if you want kids’ eyewear to last), you should consider choosing scratch resistant or scratch proof options. These days, most eyeglass lenses do have built-in scratch resistant coating, but it is not universal, so when talking with our optician, make sure that you let them know you want your lenses to have a protective coating. You can also ask them about the different warranties on lenses treated to be scratch resistant and on those without such treatment.

Anti-Fog Coating

As opposed to the previously discussed lens coatings, anti-fog coatings are a much more niche add-on for your eyeglass lenses. Anyone who’s worn glasses in the winter has experienced them fogging up when they go into a warmer location from the cold outdoors. Fogging of your personal lenses, just like that of your car’s windshield, can become a safety issue, as it temporarily limits your ability to see.

In more recent days, with so much of the world wearing masks, glasses wearers have all experienced the irritating fogging up of lenses caused by most masks not creating an airtight seal over your nose.

Options for anti-fog coatings include the factory-applied coating Fog Free, which prevents the condensation of moisture on the lenses that leads to fogging, wipes and cleaning cloths for glasses that prevent fogging, and liquid which can be applied to lenses that keeps the lenses fog free for up to a week according to the manufacturer.

Anti-UV Coating

While everyone is familiar with the (ultraviolet) UV ray protection provided by sunglasses, an additional form of UV protection exists in the form of a protective dye that can be applied to lenses of all types. Note that many types of lenses have 100 percent protection from the damaging UV rays built in, so these would not require any additional coatings. It is very strongly advised that you make sure any glasses you wear provide this protection, to avoid potential eye issues in the future. If you aren’t sure whether your eyewear includes proper UV protection, ask our optician to check them for you.

Common Questions

The answer varies and is dependent on a few factors. Frame measurements, width and length, will contribute to lens thickness as well as the power of the lens. There's no real way to predict with certainty the thinness of a high index lens pre-cut but general rule of thumb is somewhere between 1-3mm thinner compared to lower index material.
While not necessary, Anti-glare treatments are generally recommended for glasses and for good reason. Anti-glare or anti-reflective coatings come with a bevy of benefits. They eliminate glare from incoming light which provides for more crisp vision. Also, most anti-glares come with secondary benefits such as scratch and water resistance which helps to keep the surface clean and clear.
This is another tricky one because there's no one size fits all approach. We have to consider the patient, diagnoses, frame and Rx before we make a determination regarding AR coatings. Generally speaking, with the people who fit into "normal" Rx ranges and diagnoses most AR coatings would suffice. It really depends on usage of the Rx but your standard Super Hydrophobic Anti-Glare coating would be a good place to start for anyone.
Anti-reflective coating is almost just as it sounds. It is a very thin coating that's applied to the lens to help light move more cleanly through the lens. What this means is that the incoming light gets to your retina without bouncing around or heading in other directions. This reduces glare and makes vision a touch sharper. Some anti-glare coatings also have added benefits. Some coatings are also hydrophobic, meaning they repel water. Some also provide added scratch, dirt and dust resistance.
This depends on a few factors. AR coatings can last anywhere from six months to seven or more years and here's the breakdown. Just like everything else, there are different companies offering different tiers of AR coatings. Not surprising, the most expensive usually last the longest. Generally, if you keep your A coatings away from chemicals, extreme and prolonged heat exposure, clean appropriately, you can get a long life from them.
Hardly anything is necessary when it comes to lenses, aside for the proper fulfilling of the Rx. However, there are things to be done that can improve the overall optical experience like adding an anti-scratch/anti-reflective coating to your lenses. So, let's make a distinction from the get go to avoid confusion later. All anti-scratch coatings are also anti-reflective or anti-glare but not all anti-reflective coatings have a scratch resistant quality. This is important when deciding on what type of anti-reflective to get on your lenses. Every anti-reflective is constructed differently and some offer just the refractive qualities of an anti-reflective while others incorporate the scratch resistance element as well. While it isn't necessary there are a myriad of benefits to choosing a scratch resistant coating for lenses. Not only do you get the benefits from your standard AR lenses but you'll also get that smoother, hydrophobic, scratch resistance which can contribute to an increase in lens longevity. Meaning, with a little bit of care, you'll get a lot more wear. Furthermore we strongly recommend getting scratch resistant coatings for children's glasses, because kids will be kids.
In my experience, there's only one trusted method for increasing visibility at night and that's an anti-glare coating. Some providers suggest using differing tints, such as yellow tints, with an AR coating. Tinted lenses filter out a spectra of light which overall reduces light data that goes into the retina and in low light conditions this can prove dangerous. The most effective and virtually danger free method is an AR coating. As of late, companies have produced specifically formulated AR coatings to reduce glare for night driving. The goal is to reduce diffraction, which is light bouncing around and away from the focal point of the lens, resulting in glare such as halos, without reducing the light coming in that's necessary to see an image. Much like when we see oncoming headlights and they're engulfed in a ring of light. An AR coating helps reduce this ultimately let us see more of what's important, the road.
So essentially all lenses when they're poured or cast have UV protection built into them. You can add to this protection with transition or photochromic lenses which block all UVA and UVB rays. Anti-glare coatings also offer protection as well as choosing to polarize your lenses instead of tinting them or getting transitions.
The highest index you can get for lenses is the 1.74
Your Guide to the Different Lens Coatings
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Summary

Lens coatings for glasses are not something which often comes to mind right away when choosing a pair of glasses, but they are often worth having despite the added cost. Whether you want extra protection for the lenses themselves, or added benefits and protections for your eyes, options are available. Depending on how, when, and where you intend to wear your glasses, you will be able to determine which options are best for you. If you have any specific questions, don’t hesitate to contact us.

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