Office lighting and screen glare frequently cause computer eye strain headache, computer use in offices with LED and fluorescent lighting in particular. The light sensitive and those with fluorescent light sensitivity are particularly vulnerable as their problems appear to have the same cause: disproportionately high blue light content emitted by LED and fluorescent lights. This post draws from vision and work ergonomics science to suggest ways to reduce LED and fluorescent light headaches with five different types of blue filtering glare screens.
“Our cubicle farm office (…) is undergoing “lighting wars.” One person asked to have the lights above his cube removed because the glare gave him headaches. That prompted another person to ask if the lights above her cube could be taken out, and then another, and another. (…) Whole swathes of the open plan floor were suddenly plunged into total or semi-darkness, with no light source but glowing monitors”.
The article on office lighting wars (from which the above quote is taken) stirred up a lively conversation. Many (of the 350) comments confirm that office lighting disputes are not uncommon.
One obvious conclusion to office overhead lighting wars is that office lighting is a problem of health and productivity – individual and collective. Different people have different lighting needs, different light sensitivity and eye strain headache thresholds.
It is therefore very difficult to find one solution that would suit everyone. Lucky are those who can tailor their office lighting to their personal needs, perhaps to the extreme of reflection and glare free computer lighting.
Clearly the extreme solution applied in the lighting war above is not the best. Turning the lights off initially feels soothing, but working in darkness is a situation of glare, i.e. high contrast in brightness between computer screen (bright) and its surroundings (dark). And glare is certainly one of the causes of computer eye strain headache.
Computer eye strain headache and fluorescent light sensitivity: The science of office lighting
Reducing computer eye strain headache and other symptoms associated with overexposure to digital displays is a complex issue. Good lighting or illumination has long been considered a most important workplace design task affecting visual comfort (Effects of VDT workstation lighting conditions on operator visual workload; 2008).
However, there are many – often conflicting – issues to consider: visual performance, visual comfort, energy conservation, visual ambience, interpersonal relationships, biological clock, stimulation, job satisfaction … (The influence of controllable task-lighting on productivity: a field study in a factory; 2007).
Consequently, research reports often contradict each other (The Impact of Light Including Non-Image Forming Effects on Visual Comfort; 2013).
However, the confusion may soon be clarified: recent findings suggest that light induced pain may be related more to the wavelength, i.e. light’s spectral power distribution, than to the intensity of the light exposure.
Disclaimer: My interest in vision science comes from my problems with light sensitivity (photophobia), discomfort glare, and computer eye strain. I am not a vision scientist.
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The scientific conclusions with respect to office lighting, visual comfort, eye strain headache, etc… are mostly based on small samples. Even among those few people there are always exceptions that don’t fit statistical conclusions. Therefore some of the findings mentioned below may apply to many but not to you. For example, in the above cited lighting war it seems that their cubicle farm lighting was OK for many, but too harsh for the rest – obviously not an insignificant group either. It is important to realize that we have different thresholds to light induced pain.
Confusion: Brighter lights for better performance. Undesired side effect: Computer eye strain and hence worse performance.
Many studies show that exposure to higher levels of light result in increased alertness and performance (Effects of luminance and illuminance on visual fatigue and arousal during digital reading; 2014). Subsequently offices tend to be brightly lit, ~500 lux on the work surface (Effects of font size and glare on computer tasks in young and older adults; 2014). However, those studies tested vision at different lighting levels during relatively short periods of time. When testing time is extended to examine accumulated visual fatigue, nearly half lower illumination ~300 lux or below proves less eye straining yielding better medium and long-term performance (Display technology and ambient illumination influences on visual fatigue at visual display terminal workstations; 2000).
Confusion: Bluer light for better visual acuity and better energy efficiency. Undesired side effect: more visual discomfort – eye strain headaches.
Research has also suggested that cool light (higher light Correlated Color Temperature – CCT, e.g. ~5500-6500 K – with high blue content) improves visual acuity when compared to traditional, warmer light ~3500 K. Conclusion: energy could be saved by using cooler light because no loss of vision results from lower luminance levels (Visual acuity depends on the color temperature of the surround lighting; 2002. A comparison of traditional and high color temperature lighting on the near acuity of elementary school children; 2006). Such findings may have influenced the shift to widespread use of cooler light sources (initially fluorescent and later LED lamps).
Unfortunately these conclusions are also based only on short-term effects of higher blue light content, without paying attention to visual comfort and eye strain headache incidence.
Recently it was demonstrated that high blue light content is visually uncomfortable causing eye strain headache and other eye strain symptoms (Levels of visual stress in proficient readers: Effects of spectral filtering of fluorescent lighting on reading discomfort; 2015). Moreover, contrary to the initial belief that fluorescent light sensitivity is due to fluorescent light flicker, it was suggested to be a consequence of relatively high blue light content in fluorescent light (Spectral filtering of fluorescent lighting: Effects upon reading and visual discomfort in slow readers; 2012).
5-12% of us (or more?) suffer from glare and LED/fluorescent light sensitivity
It’s been estimated that between 5% and 12% of general population has severe symptoms of visual stress, and implied that most of these people (though not all) suffer due to disproportionately high blue light content (Levels of visual stress in proficient readers: Effects of spectral filtering of fluorescent lighting on reading discomfort; 2015). Since severity of symptoms constitutes a continuum (idem.) it is possible that the proportion of the population that suffers from light induced eye strain headache and fluorescent light sensitivity is even greater. Those beyond the 5-12% simply take longer – months, perhaps years of gentle eye abuse – to take notice. After that the symptoms become severe and it can be a nightmare.
Eye strain headaches are exacerbated by blue light: High sensitivity ~430-520nm, peak ~480nm
Studies of migraine patients who are visually (almost) blind, but maintain intrinsically photosensitive retinal ganglion cells (ipRGCs) intact, suggest that blue light aggravates migraine headaches (A neural mechanism for exacerbation of headache by light; 2010).
ipRGCs transmit non-image-forming signals – among others of pain induced by light – from other photoreceptors to the brain (ipRGCs are the primary but not exclusive circuit for light aversion; 2012).
Moreover ipRGCs also capture non-image-forming information. They form a photosensitive net across most of the retina with peak sensitivity around 480nm and are highly sensitive between ~430nm and ~520nm (Diagnosis, pathophysiology and treatment of photophobia; 2016).
Eye strain headache threshold level is lowered by our natural blue light filter: High absorption ~420-500, peak ~460nm
Macular pigment (yellow spot) absorbs light almost exclusively in the blue region of the spectrum with peak absorbance at ~460nm and high absorbance between ~420nm and ~500nm (Measuring macular pigment optical density in vivo: a review of techniques; 2011) because blue light provokes discomfort glare (photophobia) at substantially lower intensity levels than longer wavelengths (Retinal sensitivity to damage from short-wavelength light; 1976).
Macular pigment protects only the macula, a tiny but the most photosensitive area of the retina where vision is sharpest. The macula is also by far the most sensitive to light induced pain since it is the area that is most highly exposed to blue light damage (The visual effects of intraocular colored filters; 2012. Enhancing performance while avoiding damage: A contribution of macular pigment; 2013).
MPOD: when lighting needs get personal
Research suggests that the most common cause of intrapersonal variation in light sensitivity and eye strain headache threshold might be different levels of macular pigment optical density (MPOD) – macular pigment’s blue light filtering capacity (Macular pigment optical density and photophobia light threshold; 2006). Moreover, the effect of low discomfort glare (photophobia) threshold to blue light tends to be exaggerated in people with low MPOD (Action spectrum for photophobia; 2003).
Conclusions: Different MPOD levels cause lighting wars. The painful part of screen glare and office lighting is blue (in most cases).
This is (just) my hypothesis on what causes lighting wars. There appear to be no research reports considering MPOD, ipRGCs, and computer eye strain headache.
Lighting wars are caused by computer screen blue light and blue light from LED or fluorescent lighting
In multi-person offices, particularly with people aged over 35, there are bound to be people with lower MPOD – maybe that’s you?
Due to low MPOD you have low tolerance to blue light emitted/reflected by your computer screen, and LED or fluorescent lights.
In due time – perhaps after months or even years of gentle but persistent (8+ hours/day) abuse – your eyes start calling for help in the form of one of the symptoms of computer eye strain (visual stress): computer eye strain headache, dry eyes, general tiredness, etc.
Initially it is just a gentle irritation and thus ignored … but slowly the symptoms become debilitating and you can’t ignore them any longer.
It also becomes evident that it has something to do with light, brightness – particularly from your computer screen.
The first solution you try is to lower computer screen brightness in one way or another – initially it feels better, but eye strain persists because:
- lower screen brightness, in otherwise bright office, reduces text to background contrast which makes your eyes strain more
- not knowing any better you might use the wrong colors for screen background (e.g. blue, green or gray) thus maintaining or even increasing the relative dominance of blue light emitted by your screen (s)
- you are still exposed to the blue light from office lighting
Then a second solution is applied: reduce the brightness of general lighting when not turning lighting off completely.
But that is not a good solution either:
- it makes your coworkers (the less blue light sensitive) uncomfortable which starts a lighting war,
- and it creates a situation of glare (bright screen in much darker environment).
Does this sound like something you identify with? Do let me/us know in comments below or by contacting me.
Clearly, there are better solutions, neither terribly difficult, nor expensive.
Solutions to your eye strain headaches and fluorescent light sensitivity
Before attempting to apply the solutions suggested below make sure you are indeed blue light sensitive (some people experience visual stress due to other wavelengths). You might also want to make sure that your eye strain headache is not due to other causes (that tend to be more frequent than blue light).
As established, there are two sources of blue light of unnaturally high intensity relative to longer wavelengths that might be causing your eye strain headache:
- your computer screen, and
- your office lighting (cool LED and fluorescent in particular).
The different solutions suggested below might deal with one or both blue light sources.
Solution principle: use a blue light absorbing glare screen or filter to make spectral power distribution of light reaching your eyes more natural
The solution to computer eye strain headache from lighting is inspired by spectral characteristics of natural light sources. It is particularly reasonable to expect it to work if you don’t have nearly as many problems with eye strain headache when in natural settings.
If you compare spectral power distributions (SPDs) of natural light sources (sun, moon, candle/fire) to LED or fluorescent lights (see spectrograms above) you’ll notice that natural light sources’ SPDs are much smoother and without accentuated peaks or spikes in the blue range.
Spectral power distribution of natural light sources: sun, moon, and candle. (Note: the scale on the vertical axis is very different in each image – click on images for more detail). Source: fluxometer.
Hence, the goal of proposed solutions is to make spectral power distribution of light reaching your eyes more natural, i.e. relatively less intense in the blue part of the spectrum and smoother (more uniform) across the visible spectrum.
For example, in one study visual stress was effectively reduced by applying a translucent (pale orange) filter to fluorescent light tubes (Levels of Visual Stress in Proficient Readers: Effects of Spectral Filtering of Fluorescent Lighting on Reading Discomfort; 2015). The filter blocked shorter wavelengths considerably more than longer wavelengths.
Reducing blue light from your computer screen: a virtual blue glare screen
By far the best way to reduce the amount of blue light emitted by digital screens is through software manipulation of the colors displayed.
Blue light filtering apps that use color transform approach reduce contrast far less than any other blue glare screen, such as apps that use overlay approach or physical screen glare filters (screen protectors or colored filters). This is important because low text to background contrast is another source of computer eye strain headache.
There are two ways to reduce emissions of blue light (and subsequently eye strain headaches). Both are free, use color transform approach, and can be used simultaneously to complement each other and cancel out some of their weaknesses:
1. Change background (and text) color
This is a DIY solution which is carefully explained in this guide. Its drawback: you cannot affect the colors of some objects (mostly images and icons). Advantage: it allows you to choose the perfect colors for your eyes.
Beware, mere dimming (for example using grey background) seems to help some people but if through the reduction of contrast and brightness.
However, if you have blue light sensitive eyes you want to avoid colors with high blue content (cool colors like white, blue, purple, green, gray). You should consider limiting your selection of colors to those with Blue=0 on the RGB scale. Also Red (x) should be (considerably) greater than Green (y). These tend to be warmer colors – shades of red, yellow, brown, orange. (Try different colors and shades to see which make your eyes more comfortable).
2. Install a blue light filtering app: f.lux or Iris
F.lux was designed to combat insomnia caused by blue light emitted by digital screens. Hence it’s interface is not perfect for reducing computer eye strain headaches, but many people use it for this purpose. Moreover you cannot choose the colors – it makes your screen look warmer, yellow-ish or red-ish. Otherwise it is a great app, probably the best and most used blue light filtering app. I highly recommend it (see this, this, and this post on how to use f.lux to relieve eye strain headache).
[Update] Iris (commission link) has more recently been developped specifically to reduce eye strain. Essentially it does exactly the same as f.lux, but its interface and some options are adapted for people who suffer from eye strain.
Combining 1. and 2. blue glare screens
I am more blue light sensitive, so I have to use f.lux in combination with the DIY text and background color change. It takes a bit more fine tuning, but by using both you can reduce most of your screens’ blue light emissions, choose the most suitable color for you, and also take the blue out of the icon’s and other objects that you can’t control with the DIY approach.
3. Use a physical glare screen
Since physical glare filters reduce contrast and introduce refractive error I only recommend color filters if you have a glossy screen and cannot get a matte. See this post for ideas of colored glare screens and their blue blocking capabilities.
Note that clear screen protectors, even when claiming to filter blue light, do so very, very modestly. You can’t block blue light and see it too.
Reduce LED and fluorescent lighting eye strain headache
4. Install warm white light bulbs
Changing cool white with warm white (CCT: 2700K – 3000K) LED (commission link – Amazon) or fluorescent bulbs (commission link – Amazon) is the most obvious solution if your eye strain headache is caused by blue light from lighting.
5. Install colored light bulbs: Paint as blue glare screen
If warm white bulbs are still “too blue” for you, you can try colored LED or fluorescent light bulbs. Unfortunately I was unable to find data on their spectral power distribution, but in principle yellow should take some blue light out and orange most if not all. A red coat on a bulb should really block all of blue light out (and some green), but it might not be bright enough and likely an overkill.
You can find colored light bulbs on Amazon (commission links):
A DIY solution is to paint your existing light bulbs with orange or yellow transparent glass paint (commission link).
Consider also the colors of your office (walls, curtains, furniture, floor) as an additional measure to cut down on blue glare. Choose colors that absorb blue light, namely warm colors: reds, oranges, yellows and browns (see image).
When changing light bulbs is not possible your options are either blue light filtering eyewear or lamp blue glare screen.
6. Blue light filtering eyewear as glare screen.
Tinted lenses might be an excellent solution for eye strain headache. Glasses (wraparounds in particular) reduce the amount of blue light entering your eyes whether it comes from lighting or digital displays.
Another clear advantage of eyewear over some other solutions is that it doesn’t provoke lighting wars. Eyeglasses only affect you – the lighting conditions of your coworkers (many of whom are not blue and fluorescent light sensitive) remain unchanged.
Consider adding power to the glasses to make your eyes fatigue less, if you feel your computer eye strain may also be caused by near work required by digital devices. Most glasses marketed as “computer glasses” do that.
Finally, it is wise to get anti-reflective (AR) coating on both inside and outside of your glasses’ lenses because of its several benefits: increased transmissibility, reduced surface reflections and ghost images, decreased glare and UV transmission (Anti-reflective coatings reflect ultraviolet radiation; 2008).
There are many spectacles that claim to filter blue light available on the market. The most obvious characteristic of blue filters is their color: yellow, amber, orange, red, brown… However, despite appearing similar in terms of their color appearance (and despite their blue-block claim), different lenses of the same color may have dramatically different spectral transmission characteristics (The visual effects of intraocular colored filters; 2012).
If you think blue light filtering eyewear is what you need and you want to make an informed purchasing decision see this collection of 10 blue light filters to relieve computer eye strain, help you sleep better, etc. It provides spectral transmittance data for most of blue light filtering eyewear (whenever publicly available).
FL-41 tint to reduce fluorescent light sensitivity, migraines and blepharospasm
Since eye strain headaches are often associated with fluorescent light sensitivity it might make sense to single out eyewear with FL-41 tint. FL-41 was initially designed precisely for fluorescent light sensitivity sufferers. Later it was also shown that FL-41 tint relieves migraine and reduces some symptoms of blepharospasm (Diagnosis, Pathophysiology, and Treatment of Photophobia; 2016). There is no guarantee, however, the tint will work for you, although it’s worked great for many. Unfortunately the only way to find out is by trying. Hence, make sure you check the return policy on any glasses you might try.
Two internet companies have been singled out as quality providers of FL-41 tinted glasses and or contact lenses by the above cited report. The first is Axon Optics (commission link). Below you may see spectral transmission characteristics of Axon Optics FL-41 light sensitivity and migrane relief glasses (indoor lens) and its filtering effect on an LED and CFL light sources spectral power distributions (black curve: unfiltered SPD).
The black curve shows unfiltered spectral power distribution of an LED and fluorescent light source (center and right images). Data/image source: Fluxometer.
The other provider of quality FL-41 tint on their migraine relief and fluorescent light sensitivity eyeglasses is TheraSpecs. Spectral transmittance may be found here. You can buy from TheraSpecs via Amazon (commission link) or directly: TheraSpecs online shop (no-commission link).
If you feel lost in the myriad of blue light filters, and uncomfortable reading and understanding spectral transmission curves see this guide: How to pick the best blue filter for your light sensitivity problem.
7. Screen glare from LED and fluorescent light bulbs or tubes
Filtering blue light from fluorescent light bulbs was effective in reducing visual stress according to the following research reports:
- Levels of Visual Stress in Proficient Readers: Effects of Spectral Filtering of Fluorescent Lighting on Reading Discomfort; 2015 – Filter used: LEE FILTERS 205 1/2 C.T. orange, and
- Spectral filtering of fluorescent lighting: Effects upon reading and visual discomfort in slow readers; 2012 – Filter used: LEE FILTERS 206 1/4 C.T. orange.
Below is an example of the effect of an LED or fluorescent light filter.
The effect of amber fluorescent tube sleeve filter (source).
A cheap, DIY solution or test of blue light filtering effectiveness against your eye strain headaches
To see if a blue light filter might help you with your eye strain headaches and fluorescent light sensitivity here is a DIY version of a filter. In the images below you can see one of my setups.
The DIY fluorescent filter on a fluorescent office light: Left – workstation with fluorescent lighting, no filter; Center – a piece of cloth (off-white, fairly translucent) tucked arround the edges of the lighting fixture; Right – the effect of the filter (in this case principally light intensity reduction and dispersion – use colors (for example blue light absorbing red, orange, yellow, tan/brown) to make the light even less harsh, i.e. warmer.
The office was very bright and glary.
Unfortunately I knew nothing about blue light and its association with eye strain headache which is why the “filter” color is not blue light absorbing. Light dispersion and brightness reduction were the only aims of that glare screen.
For your setup choose a blue light absorbing (shades of yellow, orange, red) cloth. It should be translucent / thin enough to let part of the light through.
Perhaps the cheapest way to find a suitable cloth is to buy a curtain and cut it (unless you already have something suitable at home). If you feel it lets through too much light try covering the light fixture with two layers of cloth.
Here are two examples of curtain cloth you might consider ordering: orange, and yellow curtain (commission links). (In principle fluorescent, CFL or LED lights shouldn’t get hot enough to melt/ignite the cloth, but do pay some attention to the issue; make sure you don’t place the cloth very close to the light bulbs / tubes).
Once the blue light filtering glare screen is installed you should immediately feel an improvement if your eye strain headaches are caused by blue light from lighting. If you notice nothing and you used a yellow cloth you might consider using orange or red. Orange and particularly red absorb more blue light than yellow color – if this doesn’t help, than your eye strain headache is likely due to other sources.
As you continue working with this blue glare screen for some time your eye strain symptoms should ease further.
Once you are certain that what your eyes need is a blue light filter for your office lighting, you might consider improving on aesthetics and also on blue light filtering characteristics with the following products:
Color selection is unfortunately extremely limited and spectral transmission characteristics are unknown. Again, if blue light sensitive, go for warm colors. (Personally I’d stay away from the ones that appear blue, although apparently they positively influence the mood in some people). You may buy classroom light filters on Amazon (commission link) or Mayer-Johnson (no commission).
9. Color sleeves as glare screens for fluorescent tubes
This specific blue light filtering solution was applied in the above mentioned scientific experiments that show the benefits of blocking blue light from office and/or classroom lighting.
A colored fluorescent safety sleeve or tube guard is a very effective solution. A fluorescent tube is inserted inside the colored sleeve/tube. In this way you may adjust the feel of your office light however you want.
Unfortunately the only reference to spectral transmission of the color sleeves is that the Dark Amber (far right image below) “protect to 525 Nanometers“. It is, however, reasonable to assume that the yellow sleeve/tube filters blue light significantly up to 430-460nm and amber (orange) up to 480-520nm.
Fluorescent sleeves / tubes: controlling spectral transmittance
If you’d like to know spectral transmittance of your fluorescent colored sleeves in terms of their spectral transmittances you might check out the products of Lee Filters or Rosco. There are lots of color options with different spectral transmission characteristics, that you’ll be able to view on their websites.
You might also find useful this list of Lee Filter to Rosco equivalents.
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