Eye strain from screens: the 20-20-20 rule and more

In short

• Prolonged screen use will not permanently damage your eyes, but it can cause discomfort.
• People normally blink about 15 times a minute but only about 5 to 7 times while using screens, which dries the surface of the eye.
• Every 20 minutes, look about 20 feet away for 20 seconds. This is the 20-20-20 rule.
• Position the screen about arm's length away, slightly below eye level, with brightness matched to the room and glare reduced.
• See an eye doctor if symptoms persist, and get urgent care for sudden vision changes or eye pain.

Why your eyes get tired

Screen use reduces blinking, and every blink spreads a fresh layer of tears over the eye. With fewer blinks the surface dries, which brings dryness, stinging or tearing. Sustained close focus adds to the strain.

Typical symptoms are blurred vision, achy or uncomfortable eyes, and dryness with tearing or stinging. Long hours on screens, air conditioning or heating, and dust or wind in the room can all make dry eyes worse.

VR headsets and 3-D movies can add to the strain, because the eyes must converge and focus at different distances than the screen's fixed focal point. If you notice that symptoms appear mainly with one device or one task, that clue is worth sharing with your eye doctor.

The 20-20-20 rule and other breaks

The American Academy of Ophthalmology describes it this way: every 20 minutes, look away about 20 feet in front of you for 20 seconds. It gives your focusing muscles a rest and reminds you to blink.

• Set a reminder on your phone or computer, because the rule is easy to forget once you are absorbed in work.
• Blink often, perhaps with a note on the screen as a reminder.
• Look at something distant now and then, such as out a window.
• Stand up and stretch between longer tasks.
• Pair eye breaks with breaks for your neck and back.

None of this needs special equipment. The point is to build a rhythm of short pauses into the day, so that looking away becomes automatic instead of something you only do when your eyes already hurt.

Screen and room setup

1. DistancePlace the screen about 25 inches away, roughly arm's length.
2. HeightKeep the screen just below eye level, so your gaze is slightly downward.
3. Brightness and contrastMatch the screen's brightness to your surroundings and increase contrast so text is easier to read.
4. GlareA matte screen filter can reduce glare. Position the screen so windows are not directly in front of or behind it.
5. AirAvoid blowing air toward your face, and use a humidifier in dry rooms.

Good lighting also reduces strain, according to MedlinePlus. If you struggle at a normal distance, ask about computer glasses, which are prescription lenses set for screen distance.

Dry eyes: what helps

Dry eyes happen when you do not make enough tears or your tears evaporate too quickly. Beyond screens, risk factors include being over 50, wearing contact lenses, air-conditioned or heated rooms, wind, dust, smoking, alcohol, certain medicines, and conditions such as blepharitis, Sjögren's syndrome and lupus.

• Use artificial tears when the eyes feel dry. A pharmacist can recommend eye drops, gels or ointments.
• Clean your eyelids daily: apply a warm, not hot, flannel, gently massage the lids, then wipe away oil and debris.
• Use a humidifier in dry rooms and avoid windy, dry or dusty places.
• If you wear contact lenses, switch to glasses to rest your eyes, never sleep in lenses, and follow cleaning instructions.
• Do not stop a prescribed medicine without medical advice.

Glasses: computer vs blue light

The AAO separates computer glasses, which are prescription lenses set for screen distance, from glasses that block blue light, and the page does not say that blue light glasses are effective. Before buying either, an eye exam can show whether your current prescription suits your screen distance.

For children, the same habits apply: breaks, a sensible distance, good light and regular eye exams. If a child squints, moves close to the screen or complains of headaches, book an eye exam.

Red flags: urgent symptoms

Red flags: call 911 or go to an emergency department for sudden loss of vision, double vision, flashes of light, wavy lines, black spots, light that hurts your eyes, a very dark red eye, a red eye with severe headache and nausea, or an injury or something stuck in the eye. Do not drive yourself.

Get same-day care for a painful red eye, and especially a red eye if you wear contact lenses, which could signal an infection. MedlinePlus lists blurred vision with eye pain among symptoms that need an eye specialist right away.

When to see an eye doctor

Book a routine visit if tiredness or headaches persist despite better habits, if dryness continues after a few weeks of home care, if your glasses or lenses are old, or if your eyelid shape changes. A comprehensive eye exam can catch eye disease early, often before warning signs appear.

How often you need an exam depends on your age, risk factors and health. People with diabetes should have one every year. Questions to ask: Is my prescription right for my screen distance? Do I have dry eye? Which drops suit frequent use? Could any of my medicines be drying my eyes?

Questions and answers

Sources

1. American Academy of Ophthalmology — Computer usage and eye strain
2. NHS — Dry eyes
3. MedlinePlus — Eye care

Sources checked on 29 October 2026.