Computer Glasses: How They Really Work
In this article I hope to answer two very common questions regarding computer glasses. First, what are computer glasses and how do they work? And second, what are the benefits or possible long term negative effects?
Let’s get right to it.
What are computer glasses?
By definition computer glasses are glasses that are intended to be worn in front of a computer monitor. Though most companies that manufacture “computer glasses” actually target a demographic which spends a large portion of the day in front of some sort of digital device. It could be a computer monitor, tablet, cell phone or even a TV. So when we talk about computer glasses today, i'm referring to digital device glasses.
All computer glasses have similar coatings and features but before I tell you what those are I want you to understand the problem that these glasses attempt to solve; Or better said, the symptoms they try to alleviate.
Digital Eye Strain (Computer Vision Syndrome)
Computer Glasses attempt to reduce the symptoms of Digital Eye Strain. It could be dry eyes, blurry vision, headaches, double vision or extreme eye fatigue. These are all byproducts of spending hours at a time in front of a digital devices without properly resting your eyes. Here are the lens options commonly found on computer glasses:
Light from self luminous devices cast reflections on your lenses which can be both distracting and annoying. A good quality Anti-Reflective coating will allow more light to pass through the less and increase your visual acuity.
Related Article: Standard vs. Premium AR Coatings
Blue Light Filter
The amount of blue light emitted by digital devices has yet to be scientifically labeled as dangerous or harmful to the anatomy of the human eye. What has been proven is that blue light has negative effects on our Circadian Rhythm, Melatonin levels and sleep continuity.
The most common request for computer glasses is blue light filtering. This can be accomplished in one of two ways:
There are specific AR coatings designed to "bounce" harmful blue light off the front surface of the lens. Crizal Prevencia, Zeiss DuraVision Blue Protect and TechShield Blue are just a few options. Keep in mind that these coatings actually cause more reflection than a standard AR coating. They have a noticeable pink or blue hue and they typically only block roughly 20% of harmful blue light.
Left: TechShield Blue. Right: Crizal Alize
Another way to filter blue light is with a filter placed in the lens itself. Lenses by BluTech and Shamir Blue Zero will combine a low color AR with a proprietary blue light filter within the lens itself. The greatest advantage to this option is the higher BPF (amount of blue light being filtered) and virtually colorless lens. Where blue light AR coatings have a BPF of ~20%, in-lens filters can range from 20% to over 90%, with plenty of options in between.
When we focus on an object that is within 18" of our face, our eyes slightly converge. Holding our eyes in this position for hours at a time will eventually lead to eye muscle fatigue. A lens with a slight magnification (+.25) can support keeping the eyes in this position and in turn reduce the stress placed on the eye muscles.
Gunnar Optiks and Felix Gray have lenses with magnification though, at the moment, only Felix Gray gives you the options to order your glasses with or without magnification without having to pay extra. Keep in mind that some people simply can't adjust to lenses with magnification. Try both and see what works best for you.
What are the benefits or possible long term negative effects?
You would be led to believe that the main benefit of computer glasses is the blue light filtering but I would disagree. The main benefit is the slight magnification and decentered Optical Center on the lenses. Allow me to explain.
Computer glasses with magnification and a decentered Optical Center make your eyes feel a bit more comfortable because it helps your Ciliary Muscle relax. This muscle is widely believed to be responsible for your eyes ability to focus on things up close. It is responsible for shaping the Crystalline lens found within the eyes. Like any muscle, it will tire with extensive use, and that’s exactly what this muscle is doing when we stare at digital devices all day.
So how do the lenses help? The answer is something called “Decentration”.
All prescription lenses have what’s called an Optical Center. This is the most accurate part of the lens and when prescription glasses are made, the Optical Center is placed directly in front of a patient's pupils. This is why a patient's Pupillary Distance (Distance between both eyes) is measured when prescription glasses are made. To ensure that the patient's Pupillary Distance and Optical Center align.
Your eyes are drawn to the Optical Center, and by decentering the OC, your eyes are encouraged to remain converged.
This is the little bit of magic that computer glasses have and this is why the non-prescription version of these glasses wouldn’t provide the same feeling of relief. You can’t decenter the optical center of a non-prescription lens. The front and back surface of a non-prescription lens are parallel to each other, so light passes through the entire lens with no deviation.
Imagine two triangles placed base to base (See image below) and you’ll have a relative understanding of what a plus (magnification) power lens looks like. The point where the two bases meet would be considered the Optical Center and moving it away from the wearers true Pupillary Distance is called Decentration.
Are there any negative long-term effects to wearing these types of magnified computer glasses?
The answer is… it all depends. By this I mean it all depends on your definition of “negative”.
I like to use this analogy: Think about why people drink coffee. The most common reason is for the natural energy boost derived from the caffeine. Though most people would argue against this statement, coffee is not technically a necessity. If you want more energy in the morning you should go to sleep earlier and maybe stretch and exercise a bit after the alarm goes off. Do most people do that? No. Because of their habits and routines, coffee is now something they depend on. People say similar things about their computer glasses.
Will you feel like these glasses improve your productivity? It’s very likely. Will your eyes feel better at the end of a long day? I believe so. Will you develop a slight dependency on them? There’s a real good chance of that.
Now it’s up to you to weigh your options. On one hand you have the effects of digital eye strain (blurry vision, headaches, etc.) and on the other you have the ability to alleviate some of that discomfort but you may develop a dependency on the eyewear. Judging by the popularity of computer glasses I’d say most people would prefer the latter.
I encourage you to take breaks and allow your eyes to rest. The best AR and lens filters can't replicate a good old-fashion break. Computer glasses can help but let's not forget the reason why we need them is due to overuse of digital devices. Computer glasses can help but don't expect them to solve all your problems.