Digital eye strain: how to prevent and treat it

Do you reach mid-afternoon with tired eyes, a burning sensation or blurred vision, even though you've barely left the house? If you spend many hours in front of a computer, a phone or a tablet, you may be experiencing what is known as digital eye strain — or computer vision syndrome — one of the most common eye complaints in today's society.

The good news is that, in most cases, it can be resolved. In this article we explain why it happens, what symptoms it causes and, above all, what you can do to prevent and treat it starting today.

What is digital eye strain?

Digital eye strain is the collection of ocular and physical symptoms that arise from prolonged use of electronic screen devices: computers, mobile phones, tablets or televisions. Although it does not permanently damage your eyesight, it can significantly affect your wellbeing and daily performance.

💡 Did you know...? According to optometry studies, when we look at a screen we blink between 3 and 8 times per minute, compared to the usual 15–20 times. That is equivalent to 60% fewer blinks, which dries out and irritates the ocular surface very quickly.

The medical term is Computer Vision Syndrome (CVS), and it affects between 50 and 90% of people who regularly work with screens, according to the American Academy of Optometry.

Why do screens tire our eyes? The main causes

It is not simply a matter of "screen time". Several factors combine to bring about digital eye strain:

Reduced blinking

When concentrating on a screen, the brain involuntarily reduces the blink rate, leaving the eyes exposed and dry.

Blue light and brightness

Screens emit high-energy blue light, and if the brightness is not properly adjusted, they force the eye into constant effort.

Incorrect distance and angle

A screen that is too close, too far away or poorly angled strains posture and the eye's focusing effort.

Small text or low contrast

Reading small text, on a poor-quality background or with screen glare demands continual overexertion from the visual system.

Outdated prescription

Wearing a prescription that is even slightly out of date multiplies the visual effort in front of a screen.

No breaks

Long, uninterrupted sessions give the visual system no time to recover from accumulated effort.

Symptoms: how do I know if I have eye strain?

Digital eye strain does not only affect the eyes. Its symptoms also extend to the head, neck and concentration:

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Tired, heavy or itchy eyesThe feeling that your eyes are "asking for a rest", especially in the second half of the day, is the most common symptom.
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Blurred or double visionVision becomes less sharp, especially when looking close up. Transient double vision can occasionally appear when shifting the point of focus.
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Burning, stinging or dry eyesReduced blinking causes the tear film to evaporate, leaving the ocular surface dry and irritated.
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Frontal or temporal headacheSustained effort by the ciliary muscles that control focusing can produce characteristic headaches, often mistaken for other types of headache.
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Discomfort in the neck, shoulders or backA poor posture maintained for hours in front of the screen causes muscular tension that also contributes to eye strain.
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Increased sensitivity to lightAfter long screen sessions, the eyes can become more sensitive to any light source, natural or artificial.
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Difficulty concentratingWhen the visual system is overloaded, the brain devotes more resources to visual processing and mental concentration diminishes.

⚠️ Important: If symptoms persist after resting from screens, or if you experience frequent double vision, intense eye pain or sudden changes in vision, consult an optician or specialist. There may be an underlying cause that requires diagnosis.

The 20-20-20 rule: the simplest and most effective remedy

If you can only remember one piece of advice from this article, let it be this. The 20-20-20 rule is the most scientifically supported method for reducing eye strain during screen work:

Every 20 minutes...

Set a timer or use an app to remind you to take the break. Most operating systems have built-in screen reminders.

Look at something 20 feet away...

Focus on something in the distance (a window, the street, trees). This relaxes the ciliary muscle, which has been focusing close up for hours.

For 20 seconds

No more is needed. In 20 seconds the eye has sufficient time to relax its accommodation and the blink rate returns to normal.

Also use those 20 seconds to blink consciously several times in a row. This rehydrates the ocular surface and can prevent or relieve the dry eye associated with screens.

How to set up your workspace properly

Visual ergonomics matters as much as taking breaks. These adjustments can significantly reduce eye strain:

1

Screen distance: between 50 and 70 cm
The screen should be approximately an arm's length away. Too close forces the eye into continual accommodative effort; too far forces you to strain to read.
2

Screen height: top edge at eye level
If the screen is too high, the eyelids open wider than usual, increasing tear evaporation. If it is too low, the neck posture is affected.
3

Brightness and contrast properly adjusted
The screen brightness should be similar to that of the surrounding environment. A very bright screen in a dark room is particularly harsh. Enable night mode or "warm" mode from 7 pm onwards.
4

Avoid reflections on the screen
Position the monitor perpendicular to windows — neither facing nor with its back to them. Reflections force the eye to constantly compensate for contrast.
5

Balanced ambient lighting
Working in a very dark room with only the screen switched on is hard on the eyes. Soft, diffused background light reduces the contrast between the screen and the surroundings.

Further steps to prevent and treat eye strain

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Preservative-free artificial tears

If you have dry eye associated with screen use, a few drops of artificial tears throughout the day can relieve irritation and burning.

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Blue-light filter on your lenses

Lenses with a blue-light blocking treatment reduce exposure to this wavelength, especially useful if you work long hours on screens or in the evenings.

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Screen-specific lenses

If you wear progressive lenses, there are designs optimised for computer work (wider intermediate zone). Ask us if you notice your current progressives are not working well for screen use.

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Rest from your phone before bed

Avoiding screens in the last hour before going to sleep improves sleep quality and allows your eyes to genuinely rest overnight.

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Eye-friendly nutrition

Vitamin A, lutein and zeaxanthin (carrots, spinach, eggs) and omega-3 (oily fish, walnuts) help maintain the health of the retina and the tear layer.

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Update your prescription

An out-of-date prescription is a common and easily resolved cause of eye strain. If it has been a while since your last check, that may well be the cause.

💡 Did you know there are lenses designed specifically for screen use? If you work more than 4–5 hours a day at a computer, ask us about high-quality blue-light blocking and anti-reflective lens treatments. The difference by the end of the day is noticeable.

Eye strain or an undetected vision problem? The importance of an eye test

Sometimes, what appears to be digital eye strain actually conceals an incorrect prescription, early-stage myopia, uncompensated hyperopia or mild astigmatism that the eye has been working hard to compensate for over time. When the prescription is not right, the visual system is constantly working to compensate, and screens simply make it more apparent.

Sign	Possible cause	What to do
Strain mainly when working close up (computer, phone)	Uncompensated hyperopia or presbyopia	Eye examination
Blurred vision that improves when squinting	Myopia or astigmatism	Eye examination
Strain while wearing glasses (progressives or bifocals)	Lens design not adapted to screen work	Consult your optician
Headache when switching from computer to paper	Convergence insufficiency or accommodative problem	Optometric assessment
Eye strain from early in the day, without many screen hours	Dry eye, ocular allergy or surface problem	Ocular assessment

When should you come and see us?

Apply the 20-20-20 rule, adjust your workspace and wait a few days. If symptoms do not improve, or if any of the following apply, it is time for a professional eye examination:

Eye strain appears after fewer than 2 hours of screen use, even with breaks.
Headaches are frequent and located in the forehead or temples.
Blurred vision does not clear after resting from screens.
You have not had your prescription checked in over a year.
Your progressive lenses are not comfortable for computer work.
You are over 40 and notice your near vision is gradually deteriorating.

At Òptica Florit we carry out a comprehensive eye examination that includes assessment of accommodation, vergences and ocular surface health — the factors that most influence digital eye strain — and we advise you on the most appropriate lenses and treatments for your specific situation.

Frequently asked questions about eye strain

Do screens damage your eyesight in the long term?

Current scientific evidence indicates that screen use does not permanently damage eyesight in adults. However, in children there is concern about the rise in myopia, as time spent doing close work indoors and lack of natural light are well-established risk factors for its development and progression. In adults, the main concerns are eye strain and dry eye, both of which are treatable and reversible.

Do blue-light blocking lenses really work?

Lenses with a blue-light filter reduce exposure to the most energetic part of the visible spectrum emitted by screens. The evidence on whether they directly improve eye strain is mixed, but many users report greater comfort, especially when working at night. There is evidence that they reduce melatonin suppression when exposed to screens in the evening, which may improve sleep quality.

Is a computer screen better for your eyes than a mobile phone?

Screen size matters, but viewing distance and duration of use matter more. Mobile phones are typically used at a closer distance (30–40 cm) than computers (50–70 cm), which demands greater accommodative effort. We also tend to use phones in poor ergonomic positions. In general, prolonged mobile phone use is harder on the visual system than a properly configured computer.

My children spend many hours on screens. Should I be worried?

It is a legitimate concern. In children, excessive close-up screen use is linked to a higher risk of developing myopia, in addition to eye strain. The American Academy of Ophthalmology and other bodies recommend limiting screen time for children under 12, encouraging time outdoors (which has a demonstrated protective effect against myopia) and arranging regular eye examinations from the age of 3–4.

Can I work on screens if I have dry eye?

Yes, but you will need to take extra precautions. Eye strain and dry eye feed into each other: dry eye worsens eye strain, and screens worsen dry eye. With appropriate dry eye management (suitable artificial tears, eyelid hygiene, environmental adjustments) and the habits described in this article, the vast majority of people with dry eye can work comfortably on screens.