Do screens damage your eyes?

The 20-20-20 rule, and what it is really doing

Every 20 minutes, look at something about 20 feet (6 metres) away for 20 seconds. It works by relaxing the focusing muscle, which stays contracted throughout close work.

The exact numbers are a memorable approximation rather than a precise prescription. The principle — regular breaks from sustained near focus — is the part that matters.

Blue light glasses

Reviews of the available trials have not found convincing evidence that blue-light filtering lenses reduce eye strain. The discomfort appears to come from how the screen is used, not from the blue component of its light.

Blue light and evening alertness is a separate question, and there the evidence is stronger — but that is about sleep, not eye health. Reducing brightness and screen use before bed addresses it directly.

What does help

Four things with reasonable support: take regular breaks, blink deliberately during long sessions, match screen brightness to the room rather than using a bright screen in a dark one, and position the screen slightly below eye level at roughly arm's length.

If discomfort persists despite all of that, it is worth an eye test. Uncorrected vision is a common hidden cause, and no amount of screen hygiene fixes it.

Eye+

Our iOS app for exactly this. Runs on your device — no account, no tracking.

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