The question about the effectiveness of computer glasses in protecting your eyes against the maladies of digital screens, particularly blue light, appear often: Can glasses help eye strain; Do glasses protect your eyes from computer; How to protect eyes from computer screen using glasses; Can you get glasses for eye strain; Do computer glasses really work; etc. If you go and ask this question your favorite search engine you’ll get a lot of positive, a lot of negative, and a lot of inconclusive answers. That is because computer glasses effectiveness against eye strain depends on many objective and subjective factors. So, to answer the question in the title: Yes, they can protect your eyes, but when used properly. This article highlights one of perhaps the least known but the most common cause of eye strain for computer glasses wearers: the reflections on the back of the lenses.
Disclaimer: I am NOT a vision scientist nor a physician but a more computer glare and light-sensitive person, hence my interest in low blue light filters, eye strain, blurred vision, acuity and light sensitivity.
Should you protect your eyes from computer
There are different reasons why one might want to use computer glasses or other blue light filters: to improve vision/acuity, to prevent eye strain or computer vision syndrome in any one of its manifestations (symptoms), to sleep better, avoid age-related macular degeneration, etc.. In this article the focus is on eye strain.
Computer glasses may mean clear lens glasses with an extra power add to help eyes strain less. Nowadays, it’s become very common for computer glasses to also include some form of blue light protection because blue light from digital screens and artificial lighting is an important cause of eye strain.
There are also other ways of protecting your eyes from computer blue light. You might also consider anti-glare, or blue blocking screen protectors; contact lenses; blue light filter apps; and even your natural blue light filter – macular pigment. Each is also discussed below in terms of how susceptible they are to veiling glare.
Sources of the differences in computer glasses effectiveness
First, there are considerable differences between different computer glasses. They may block more or less blue light. Hence, different eye strain glasses may be more or less effective when worn by the same person.
Similarly, the effectiveness of the same pair of glasses may vary from person to person due to subjective differences in our visual systems. The best researched is the variability in the blue blocking capabilities of our natural blue light filter – macular pigment.
Other sources for different perception of how well a given pair of computer glasses work might be the differences in: the digital screen used; your workstation lighting; your screen-based eye use habits; the accumulated digital eye strain (how tired your eyes are) after months perhaps years of heavy digital screen (ab)use; etc.
Finally, there are also differences in how computer eyeglasses are used. By adding a filter in front of your eyes, you add another potential source of glare and reflections that may strain your eyes.
Veiling glare: Faint ghost images on the back of your glasses
Veiling glare on computer glasses is a big problem for their effectiveness. Acuity – considered as viewed image clarity, i.e. whatever a digital screen displays – may be considerably reduced by reflections of light from the lenses’ back surface (the one facing eyeglasses user).
These reflections are normally in the form of faint ghost images. They are also referred to as veiling glare. Viewing digital screens through these images can put a lot of strain on eyes.
Frequently we don’t notice veiling glare because we focus on the task beyond the glasses – on the computer screen.
That is why veiling glare is is so dangerous. Imagine your eyes’ futile and continuous effort to read off the screen through ghost images. In due time such effort may result in increased light sensitivity, eye strain, blurred vision, etc.
Subsequently, you may conclude that computer glasses don’t protect from computer eye strain.
How to spot veiling glare on computer glasses
It is difficult to take a photo of ghost images on the back of eyeglasses lenses. For that reason, the images below show reflections on the other, front side of the lenses. Ghost images on the back side are similar but normally fainter.
For example, see white reflections on the front of computer glasses lenses below. These computer glasses have amber lenses without AR. The reflections are fairly obvious.
The lenses in the next image are clear with anti-reflective (AR) coating. Hence, the reflections are more difficult to spot. But if you look carefully you can still see them. In this case, they are the most obvious in the upper area of the lens, closer to the nose.
Such reflections on the front of the lenses they don’t do much harm to the users because they normally can’t see them.
Ghost images on the back side of the lenses (the side facing the user) are much fainter because, generally, there is less light available.
However, when your eyes become strained (perhaps after months or years of looking through veiling glare), they become more sensitive to anything, including this type of reflections.
Veiling glare might be just a faint reflection of your cheek skin or of the white of your eye.
Here is how to check if your eye strain glasses might not be protecting but hurting your eyes by causing veiling glare and subsequent eye strain:
Put your computer eyeglasses on and try to focus on the back of your lens – it is not easy to focus that close, but don’t worry about seeing the details. What is important is whether you can see anything or not.
If you do, you may have discovered the cause of your eye strain (or at least one of the causes).
Note that different lighting conditions, different position of your head, etc… might lead to stronger or weaker veiling glare on your glasses.
If you use digital screens in different places, you should remember to always check for these back-of-the-lens reflections. If you can see them, you’ll know immediately that in order to prevent eye strain either you get rid of them, or you reduce screen-viewing time to the necessary minimum.
Solutions to veiling glare on computer glasses and/or screen protectors
Veiling glare is a slightly different problem depending on whether you are using computer glasses or a screen protector.
Ghost images are more or less pronounced depending, principally, on the quantity of light in the space between the filter and your eye.
No veiling glare case is when there is NO light at all to be reflected.
Also important is the type of surface on your computer eyeglasses or screen protector. Ghost images are worse (more pronounced) if the surface is more reflective and if the reflected light is less dispersed.
The worst case example might be if you imagine mirror-coated sunglasses lenses (such as the ones in the image below) but put on backward – with the mirror-coated side facing your eyes.
Hence, if your goal were to minimize or avoid ghost images, contact lenses might be the best surrogate for computer glasses. Since there is no space between a contact lens and the eye, there can be no ghost images. Unfortunately, low blue light filters in the form of contact lenses are not easily found (if you know of any, let me know).
If your goal is to filter more blue light an even better solution is to strengthen your macular pigment – which also has several other advantages over artificial blue light filters.
As far as the most common solutions to computer blue light -glasses and screen protectors- some degree of veiling glare is inevitable. But you can do a lot to minimize it:
– Anti-reflective (AR) coatings on eyeglasses lenses do help reduce this effect, but as shown above, they don’t resolve the problem 100%.
– A wide-brimmed hat (for example a Sou-wester hat – as in the images above) might be the best solution to computer glasses veiling glare.
– Glare and reflection free office lighting is another possible solution to both, computer glasses and screen protector veiling glare.