How to Protect Your Eyes When Using Your Phone for Long Periods

Digital eye strain — the tired, dry, blurry eyes you get after extended screen use — is real and increasingly common as people spend more time on phones and screens generally. The good news is that it’s manageable and doesn’t cause permanent damage for most people. The bad news is that some of the most marketed “solutions” (blue light glasses, for example) have surprisingly weak evidence behind them.

Here’s what actually works.

The 20-20-20 Rule: The Most Evidence-Based Intervention

Every 20 minutes, look at something 20 feet (about 6 metres) away for 20 seconds. This is not a tech solution — it’s a behaviour. But it’s genuinely the most evidence-backed thing you can do for digital eye strain.

Your eyes’ focusing muscles are held in a sustained near-focus position during screen use. This sustained effort causes fatigue. The 20-20-20 break allows the muscles to relax completely by focusing on a distant point.

Set a recurring timer on your phone every 20 minutes as a reminder, at least until the habit is automatic.

Blink More

Studies consistently show that people blink significantly less when looking at screens — roughly half as often as usual. Blinking is how eyes are lubricated, and reduced blinking leads to dry, irritated eyes within an hour or two.

Simply being aware that you should blink more helps to some degree. A quick eye exercise: close your eyes completely for three seconds, then blink deliberately several times. This recoats the eye surface with fresh lubricating tear film.

Screen Brightness and Ambient Light

The relative brightness between your screen and the surrounding environment affects eye strain. Eyes work hardest when there’s a large brightness difference between what you’re looking at and the surrounding area.

Don’t use your phone with maximum brightness in a dark room. Don’t use it with very low brightness in bright sunlight. Aim for your screen to be roughly as bright as the environment you’re in. Enable auto-brightness on your phone for this reason — it adjusts to ambient conditions.

Text Size and Display Settings

Text that’s too small forces your eyes to strain to resolve characters. Increase your phone’s text size (Settings > Display > Font Size) to a comfortable level. You may need to scroll more but your eyes will thank you.

Enable high contrast text if available. White text on black or very dark backgrounds (dark mode) is preferred by many people for extended reading because it reduces the amount of light the screen emits in total.

Blue Light Filters: What the Evidence Actually Says

Blue light filters (Night Mode on Android, Night Shift on iPhone) reduce the blue wavelength light your screen emits. The blue light-sleep disruption connection is reasonably well established. But the connection between blue light and eye strain specifically is much weaker in the research.

The American Academy of Ophthalmology doesn’t currently recommend blue light glasses for eye strain, noting insufficient evidence. The main driver of digital eye strain is not blue light specifically but the sustained near-focus and reduced blinking.

That said, blue light filters make the screen warmer and some people find them more comfortable for evening use. Enable them in the evening primarily for the sleep benefit (they genuinely help with melatonin and sleep quality), not specifically as an eye strain intervention.

When to See an Optometrist

If eye strain is persistent, severe, or includes symptoms like headaches, blurry vision that doesn’t clear quickly, or unusual sensitivity to light, see an optometrist. These symptoms can indicate refractive errors (incorrect prescription in your glasses) or other eye conditions that need professional assessment, not just screen time management.

Regular eye exams (annually for most people, or as recommended) catch vision changes that make screens significantly harder on the eyes without you realising it.

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