Screen time before bed: eyes, evening light and sleep at work
Screen time before bed is, for most office workers, just the tail end of a day that already started with eight hours in front of a monitor. By evening your eyes sting and sleep takes a while to come. Blue light usually gets the blame. The evidence is more nuanced. As far as we know, blue light from screens does not damage your eyes, and tired eyes have other causes.
For sleep, what counts is how much light you get in the morning and how much in the evening. This article separates the two and shows what actually helps in a normal working week.
Many of the people I coach sit at a desk all day and train in the evening. After sore muscles, their most common complaint is stinging eyes and trouble falling asleep. The two often get lumped together. How evening light and sleep are linked in general is covered in our main article blue light and sleep: do the glasses work. This one is about the working week: what the screen does to your eyes, what it does to your sleep, and what you can change.
Does blue light from screens damage your eyes?
Based on current evidence, no. The American Academy of Ophthalmology states that there is no scientific evidence that blue light from digital devices damages the eye. The 2023 Cochrane review (Singh et al.) also found no usable data on whether blue light filtering lenses protect the retina in the long run.
We say this clearly because we sell blue light glasses ourselves: we do not promise protection against eye disease. If a product claims to prevent eye damage with a blue light filter, be sceptical. For any problem with your vision, an optician or your GP is the right place to start.
Why do your eyes get tired at a screen?
Digital eye strain is common. A 2018 review (Sheppard and Wolffsohn) estimates it affects half of computer users or more. Symptoms fall into two groups:
- Focusing effort. Hours of close-up viewing work the eye muscles hard, especially with glasses that no longer match your eyes.
- Dry eyes. According to the AAO, most of us blink less when looking at screens. The tear film breaks up and the eyes sting. Dry air from central heating in winter makes it worse.
Blue light hardly features in the studies. In the Cochrane review, blue light filtering lenses probably did not reduce eye strain in the short term. Sheppard and Wolffsohn also describe the results for blue light filters as mixed and focus on other measures: an up-to-date prescription, treating dry eye and regular screen breaks.
Does the 20-20-20 rule actually work?
The rule is simple: every 20 minutes, look at something about 20 feet away for 20 seconds. A 2023 study (Talens-Estarelles et al.) tested it with 29 computer users who had symptoms. Software reminded them to take the breaks for two weeks. They took more breaks, and their eye strain and dry eye symptoms went down. One week after the reminders stopped, the effect had gone, and none of the measured signs on the eye changed during the two weeks.
So the rule helps as long as you stick to it. A break timer on your computer is the easiest way. In the UK, the HSE also expects employers to make sure display screen users take breaks or switch to other tasks, and to provide an eye test if a worker asks for one.
| Symptom | What helps | What hardly helps |
|---|---|---|
| Stinging, dryness | breaks, blinking on purpose, air that is not too dry | blue light filter lenses |
| Blurry vision by the afternoon | current prescription, distance to the monitor, looking into the distance | a brighter screen |
| Headache, tight neck | monitor height, breaks with movement | working through without a break |
| Trouble falling asleep | morning daylight, little light in the evening | night mode alone with full room lighting |
Dry air in the office or at home makes the stinging worse. How to use a humidifier sensibly, without the usual mistakes, is covered in how to use a humidifier. And if eight hours of sitting leave you with heavy legs in the evening, read heavy legs from office work.
Daylight at work: the overlooked sleep factor
For sleep, morning light matters at least as much as evening light. In a 2017 study (Figueiro et al.), 109 office workers wore a meter measuring the kind of light that affects the body clock for a week. Those who got a lot of it in the morning fell asleep faster, especially in winter, and reported better sleep. A smaller 2014 study (Boubekri et al.) compared 49 workers with and without windows at their desks. Those with windows got more light and slept longer on objective measurement. Both are observational studies, but they point the same way.
- Walk part of your commute or take your lunch break outside when you can.
- Put your desk as close to a window as possible, without glare on the screen.
- Do not wear tinted glasses in the morning. That is when you want the light.
Screen time before bed: what really counts
In the evening it flips. Light now holds back the sleep hormone melatonin, even at levels normal in a lit living room (Phillips et al. 2019). People who read on a backlit tablet in the evening instead of a printed book fell asleep later and were less alert the next morning (Chang et al. 2015). And there is one thing no pair of glasses fixes: an email from your manager at 10 pm keeps you awake whatever colour it glows.
| Time of day | Light | Glasses |
|---|---|---|
| Morning | as much daylight as possible | no tint |
| Afternoon | normal, breaks by the window | only if you find it comfortable |
| Screens after work | dim the room, monitor no brighter than needed | orange blue light glasses |
| Last 1–2 hours | warm, low light | red blue light glasses, or screens off |
The orange blue light glasses for screen days reduce 99 % of blue light in the 190 to 590 nm range, according to the manufacturer, and have no prescription. If you need corrective glasses, they do not replace them. For the last one to two hours before bed there is the red version for late evenings. Which tint suits which time is compared in red vs orange blue light glasses. Whether tinted lenses measurably improve sleep is not proven. They are a tool that takes little willpower. What a full last hour before bed can look like is set out in our evening recovery routine.
“Most office workers I coach get too little light in the morning and too much at night. Getting outside at lunchtime and switching off the main light in the evening often does more than any gadget.”
Daniel Volpe, coachWho this suits, and the limits
A good fit if you
- work at a monitor all day and stay on screens in the evening
- work from home without a clear end to the day
- find it hard to switch off and fall asleep late
- commute in the dark in winter, morning and evening
Limits
- For ongoing stinging, worsening vision or double vision, see an optician or your GP. Blue light glasses do not treat anything.
- Glasses without a prescription do not replace prescribed lenses.
- If you have slept badly for weeks, get it checked by your GP.
- Tinted lenses are not suitable for colour-critical work or for driving in the evening.
Conclusion
Blue light from screens is not known to damage your eyes; tired eyes come from close-up work and blinking less, and breaks plus the right prescription help more than any filter. For sleep, office workers gain most from plenty of daylight in the morning and little light in the evening, with tinted glasses as a sensible add-on for the hours after work. Blue light filters have no proven benefit for eye strain, their effect on sleep is uncertain, and lasting symptoms belong with an optician or GP.
Frequently asked questions
Is screen time before bed bad for you?
Does blue light from computer screens damage your eyes?
What helps with eye strain from screens?
What is the 20-20-20 rule?
Do blue light glasses help with eye strain at work?
Should I wear orange blue light glasses in the morning?
Sources
- Sheppard, A. L. & Wolffsohn, J. S. (2018). Digital eye strain: prevalence, measurement and amelioration. BMJ Open Ophthalmology, 3(1), e000146.
- Talens-Estarelles, C. et al. (2023). The effects of breaks on digital eye strain, dry eye and binocular vision: Testing the 20-20-20 rule. Contact Lens and Anterior Eye, 46(2), 101744.
- Singh, S. et al. (2023). Blue-light filtering spectacle lenses for visual performance, sleep, and macular health in adults. Cochrane Database of Systematic Reviews, 8, CD013244.
- American Academy of Ophthalmology (2021). Should You Be Worried About Blue Light?
- Figueiro, M. G. et al. (2017). The impact of daytime light exposures on sleep and mood in office workers. Sleep Health, 3(3), 204–215.
- Boubekri, M. et al. (2014). Impact of windows and daylight exposure on overall health and sleep quality of office workers: a case-control pilot study. Journal of Clinical Sleep Medicine, 10(6), 603–611.
- Chang, A.-M. et al. (2015). Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. PNAS, 112(4), 1232–1237.
- Phillips, A. J. K. et al. (2019). High sensitivity and interindividual variability in the response of the human circadian system to evening light. PNAS, 116(24), 12019–12024.
- Health and Safety Executive (HSE): Working safely with display screen equipment.
- Ractiveone: orange blue light glasses, filter range and specifications (manufacturer information)
