Our optometrists get asked this question all the time, and you've also probably asked yourself this very question that last time you purchased a pair of eyeglasses.
Are anti-reflective eyeglass lenses really worth the money?
We'll save you the time of reading this entire article, here's the punch line:
Anti-reflective eyeglass lenses are in our opinion the single best upgrade
anyone can make to a pair of new glasses.
So Why Are Anti-Reflective Eyeglass Lenses So Important?
The fundamental principle behind non-glare anti-reflective lenses (AR lenses) is to reduce the reflection of light off the surface of the lens.
By reducing unwanted glare, you improve the efficiency of the lens by increasing the amount of light that passes through it, making objects appear brighter. This principle is valid for all types of optical lenses including single vision, bifocal, and progressive.
Not all non-glare coatings however are the same; there are different quality levels and applications methods. Better quality AR coatings provide improved optical properties, enhanced vision, and improved scratch resistance.
The History of Anti-Reflective Lenses
Non-glare anti-reflective lens surfaces have been around since the 1930's when the Zeiss Optical company first introduced the idea in a commercially viable form.
The original theory behind Anti-Reflective Lenses
was developed back in the late 1800's
by John William Strutt (aka Lord Rayleigh),
the same gentleman who proved
mathematically why the sky is blue
(Answer = Rayleigh Scattering).
Non-glare anti-reflective coatings have become the standard for all optical lenses in Europe, but to this day only make up a small fraction of the lens purchases in North America.
This reduced acceptance was initially blamed on problems with earlier versions that would often craze; a process by which the coating would crack, peel or separate from the underlying lens material. Although lens crazing is no longer the problem it once was, we still see the occasional pair that fails. But don't worry. Lens manufactures provide 1 or 2-year warranties against it, and will happily replace your lenses if they fail. Drastic temperature changes are often to blame for lens crazing, and as such we probably will always see some coating failures in the winter months because of the transition been hot and cold environments.
The difference between quality non-glare lenses and less expensive versions can be broken down into 3 areas.
1. Front surface only coatings or back surface only vs. Front and back surface coatings
By only coating one side of the lens, it's less costly to apply. Unfortunately, there can still be reflections off the uncoated surface, so unwanted glare is not entirely eliminated. Coating only one surface allows lens manufacturers to grind your prescription on the other side of a preformed blank lens. Improving turn around time, but reducingthe quality of the end product.
The one application however where a back surface only coating is preferred, even in high-end lenses, is in sunglasses. This is because you want sunlight to be reflected off the front of the lens but you don't want to see the reflection of your eye.
2. Single layer coatings vs. Multi-layer coatings
A single layer non-glare application is easier to apply but must be manufactured in a slightly thicker coating (like paint, one thick coat can flake off easier or dry with imperfections). It also only provides anti-reflective properties over a tiny spectrum of light waves, so reflections still occur.
A multi-layer non-glare coating is more costly to apply but provides improved reflective properties over a large range of light waves reducing glare even more. It is also less likely to flake off, as it's applied in thinner layers.
3. The addition of a hydrophobic coating to help repel water and grease
Anyone who has owned a pair of non-glare AR lenses understands that they can get dirty easily. The manufacturers have known this for years and have now started incorporating ways to reduce this. These additional processes also help to make cleaning your eyeglasses easier.
3 Reasons to Buy Non-Glare Anti-Reflective Lenses for Your Eyeglasses?
1. Reduced surface reflection
These lenses help to improve the overall cosmetic appeal of the glasses, by allowing others to see your eyes. It draws attention away from the lens and centers it more on the frame, or makes the lenses seem invisible in rimless styles. Reducing surface reflections helps to reduce eye fatigue while working on computers, working under fluorescent lights or from ambient light from windows or floor lamps. Additionally, it helps to dramatically reduce night time glare when driving, from headlights, street lights and internal car lighting.
2. Improved light transmission
All smooth surfaces reflect light (e.g., reflections of water, snow, etc. ) and all transparent materials reflect light internally (This is why you pay big money for well-cut diamonds). Anti-reflective coatings help to reduce both of these principles. More light can pass through the lens instead of being reflected off or reflected internally, which increases the brightness of the image and improves contrast sensitivity (fine detail vision).
Typical uncoated eyeglass lenses transmit about 90-92% of light, versus well-coated lenses which transmit 98-99% of light. It may not seem like a lot, but try rolling down the window in your car and comparing the before and after, or look at your backyard through the patio door window and then open it (most car windows and home windows have no non-glare AR coatings). Even this subtle increase in light transmission can make a night and day difference in low light levels. Improved light transmission also makes your vision through glasses seem more natural.
Non-Glare AR Lenses can help improve your night vision for driving.
3. Improved Scratch Protection
One interesting property of most non-glare AR coatings is that they provide a very hard durable surface to the lens, thus making the lens more scratch resistant.
Remember, no eyeglass lens is 100% scratch proof, not even glass!
Proper care and maintenance are still required when cleaning your new glasses, but non-glare AR lenses will make them harder to scratch.
So there you have it. Do yourself the benefit of upgrading your lenses in your new eyeglasses to non-glare anti-reflective ones. Your vision will be sharper, your glasses will look better, and they will be more resistant to scratching. If you have any other questions with regards to lens coatings, don't hesitate to ask us, or talk to a Licensed Optician.
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Kingsway Mall | Edmonton | Alberta
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