Eye strain from screens in adults: what helps and what does not

Tired, achy, dry eyes at the end of a screen day are so common that most adults treat them as the price of working. Some of the advice offered for them is sound and some is expensive and does little. This article sorts the two, and then covers the part that rarely gets said: sometimes tired eyes are not about the screen at all.

What is digital eye strain, and why do screens cause it?

Digital eye strain, also called computer vision syndrome, is a group of eye and vision complaints that come from prolonged use of computers, tablets, e-readers and phones. The American Optometric Association lists eyestrain, headaches, blurred vision, dry eyes and neck and shoulder pain as the main ones.

A 2018 review by Sheppard and Wolffsohn in BMJ Open Ophthalmology divides the symptoms into two families. One comes from the focusing and eye-teaming system being held under stress. The other is external, an ocular surface that dries out. The review estimates that prevalence may be 50% or more among computer users, and that the symptoms are typically transient, although they may be frequent and persistent. The American Academy of Ophthalmology adds that the strain does not cause lasting damage to the eyes.

That last point matters. Eye strain is uncomfortable and it is worth fixing, but it is not a sign that your screen is wearing your eyes out. It is closer to the ache in a hand after a long day of writing: a muscle and a surface doing a demanding job for too long, usually in a setup that makes the job harder than it needs to be.

Do blue-light glasses help with eye strain?

Probably not. The Cochrane review by Singh and colleagues in 2023 pooled 17 randomised trials of blue-light filtering spectacle lenses in adults. It concluded that the lenses may not reduce the symptoms of eye strain with computer use over the short term, with low-certainty evidence, and that they probably have little or no effect on visual acuity. The follow-up periods in those trials ran from less than a day to five weeks.

The Cochrane authors were careful about what they could not say. The trials were small and none had a low risk of bias in every domain, and the effects on sleep were inconsistent, with three studies finding an improvement and three finding none. They also found no trial that measured macular health. So the honest summary is that the case for these lenses as an eye strain remedy is weak, and the question of long-term protection has not been tested.

The American Academy of Ophthalmology goes further in its public advice. It states that there is no scientific evidence that blue light from digital devices damages the eye, and it recommends skipping glasses that claim to protect against it. It does accept that bright screens late at night can make it harder to fall asleep, and suggests limiting screens for two to three hours before bed. Dimming a screen in the evening costs nothing. I would spend the money on an eye examination instead.

Does the 20-20-20 rule work, and what about blinking?

The 20-20-20 rule is a sensible habit, and it works on the right problem. The American Academy of Ophthalmology words it as: every 20 minutes, look at something at least 20 feet away for at least 20 seconds. The American Optometric Association gives the same rule. Twenty feet is about six metres, so a window, or the far end of the room, will do.

I would be careful about claiming more than that. The rule is practical advice that eye-care bodies recommend, and Sheppard and Wolffsohn list regular screen breaks among the management approaches for digital eye strain. I am not aware of it being proven in the way a drug is proven in a trial, so treat it as a low-cost habit, not a treatment.

The deeper issue is blinking. The American Academy of Ophthalmology says people normally blink about 15 times a minute, but only about 5 to 7 times a minute while using computers. Fewer blinks means the tear film, the thin layer of oil, water and mucus that coats the front of the eye, sits exposed for longer and evaporates. Dry, gritty, burning eyes follow. Looking away every so often resets the habit, and deliberately blinking fully a few times when you do is a fair use of those 20 seconds.

If your eyes are dry well beyond screen hours, the cause is often the oil glands in the lid margin rather than the screen. I explain that in my article on dry eyes that start after fifty.

Where should the screen sit, and how bright should it be?

The screen should sit a little below eye level, at about arm's length, with its brightness matched to the room. The American Optometric Association recommends the centre of a computer screen 15 to 20 degrees below eye level, which it puts at about 4 or 5 inches, and 20 to 28 inches from the eyes. The American Academy of Ophthalmology suggests about 25 inches, so that the eyes gaze slightly downward.

Brightness is the other half. The American Academy of Ophthalmology advises matching screen brightness to the light around you, and increasing contrast. A bright screen in a dark room, or a dim one in a sunlit room, forces the eyes to work harder on every line of text. Posture counts too: the American Optometric Association names tilting the head or bending towards a screen among the contributors to the syndrome.

Could my glasses, or my age, be the real problem?

Yes, and this is the most commonly missed cause. The American Optometric Association names uncorrected vision problems, such as long-sightedness and astigmatism, presbyopia, and inadequate eye coordination among the causes of computer vision syndrome. Sheppard and Wolffsohn list correction of refractive error and presbyopia first among the management approaches. A prescription that is a few years out of date can make a screen day harder than it should be.

Presbyopia is the medical name for the gradual loss of close-up focusing that comes with age. The American Academy of Ophthalmology says you may start to notice it shortly after age 40, as the lens inside the eye becomes more rigid and cannot change shape as easily. It also notes that uncorrected presbyopia can cause headaches and eye strain. A person who has never worn glasses can therefore start to struggle with a screen and a phone in their forties and assume the screen is to blame.

The American Academy of Ophthalmology describes computer glasses as lenses that let you focus at screen distance, and says they are not the same as blue-light blocking glasses. That is the useful distinction. A lens designed for the distance of your screen is solving a focusing problem, which is real. A tint is not. If you work at a screen for hours, say so at your eye examination, because the right prescription for reading a book is not always the right one for a monitor at arm's length.

When are tired eyes not caused by the screen?

When the tiredness does not ease with rest, when it is worse at the end of the day regardless of screen use, or when it comes with a change that you can see in the mirror. Screens are the easy explanation, so they get blamed for conditions that have nothing to do with them.

A lid that sits lower than before can make the eyes feel heavy and tired. If the droop is worse as the day goes on, that pattern has its own explanation, which I set out in my article on eyelids that droop more by evening.

Thyroid eye disease is the other one I would not want missed. The National Eye Institute lists red, irritated eyes, lids that do not close fully and bulging eyes among its symptoms. Gritty, tired, watery eyes with puffy lids and a staring look are often put down to screens or poor sleep. The signs of thyroid eye disease are worth knowing, and double vision is a reason to be seen promptly, not to buy another pair of glasses.

Eyes can also look tired without feeling it, which is a separate question that my hub article on what makes eyes look tired answers. The wider set of lid conditions sits in the eyelids section.

The American Academy of Ophthalmology advises seeing an ophthalmologist if your eyes are consistently red, blurry or watery, or become sensitive to light or painful. Add to that any sudden change in vision, a new double image, or one eye that looks different from the other. None of those is eye strain.

What can I change this week without spending money?

Four changes cover most of what is proven or sensible. First, set a reminder for the 20-20-20 break and use it to blink fully. Second, bring the screen to about arm's length, slightly below eye level, and match its brightness to the room. Third, dim the screen in the evening and keep it away from the last hours before bed. Fourth, book an eye examination if your prescription is more than a couple of years old, or if you are in your forties and reading has become harder.

If the discomfort persists after that, the likely candidates are dry eye from the lid margin, a prescription that needs updating, or one of the less common conditions above. For parents who are wondering whether the same advice fits a child, Dr Chan Li Yen covers it in her page on dry, gritty eyes, air-con and screens in children, which is her half of the question.