Guide
The 20-20-20 rule for your eyes: does it work?
Every 20 minutes, look at something 20 feet away for 20 seconds. The 20-20-20 rule is the most quoted advice for tired eyes at a screen, and there is surprisingly little research on it. We found two studies that put it to the test.
In short. In a 2023 study, 29 people with screen-related eye symptoms used software that reminded them to follow the rule for two weeks: their eye strain and dry-eye symptoms eased, then came back a week after the reminders stopped, and the surface of their eyes did not change. In another 2023 experiment, 20-second breaks every 5, 10 or 20 minutes did not prevent symptoms during 40 minutes of demanding reading. Breaks may help some people; they are not a treatment, and lasting symptoms are a reason to see an eye doctor.
The rule
Every 20 minutes, look at something at least 20 feet, about 6 metres, away, for at least 20 seconds. The idea is to relax the eyes’ focusing effort and break up long stretches of close work. It is widely cited, and, as one of the studies below notes, there is relatively little peer-reviewed evidence for it.
What the two studies found
| Study | What they did | What they found |
|---|---|---|
| Talens-Estarelles and colleagues, 2023 | 29 computer users with symptoms; laptop software tracked their breaks and reminded them of the rule for two weeks | More, shorter breaks and shorter stretches of work; eye-strain and dry-eye symptoms eased, but not one week after the reminders stopped; no change in the eye’s surface or tear film |
| Johnson and Rosenfield, 2023 | 30 young people read a demanding text on a tablet for 40 minutes, with 20-second breaks every 5, 10, 20 or 40 minutes | Symptoms rose in every session; the results did not support 20-second breaks as a treatment |
The two are not as contradictory as they look. The first followed people with symptoms through two weeks of their own work, and the reminders changed how they worked overall. The second tested short breaks within a single 40-minute session. Both are small.
What else helps
- Blink. People blink much less while looking at a screen: digital eye strain.
- Take real breaks, longer than 20 seconds, away from the screen, now and then.
- Set up the screen: a comfortable distance, and brightness that matches the room.
- Skip the blue-light glasses: the best review found little effect on eye strain: blue light glasses and night mode.
- See an eye doctor if your eyes are often red, blurry or painful, or symptoms do not settle.
A screen for glances, not hours
Lychnos Ring is not a health product and makes no health claims; it shows a line or two at a time, then goes quiet. It is in development.
Sources, read 4 November 2026: Talens-Estarelles and colleagues, the effects of breaks on digital eye strain, dry eye and binocular vision: testing the 20-20-20 rule, Contact Lens and Anterior Eye, 2023; Johnson and Rosenfield, 20-20-20 rule: are these numbers justified?, Optometry and Vision Science, 2023. Abstracts read at Europe PMC. General information, not medical advice.
Questions
What is the 20-20-20 rule?
Every 20 minutes, look at something at least 20 feet (about 6 metres) away for at least 20 seconds. It is widely recommended to ease eye strain from screens, but it has been tested in only a few studies.
Does the 20-20-20 rule work?
The evidence is thin and mixed. In one 2023 study, two weeks of reminders eased eye-strain symptoms, which came back after the reminders stopped; in another, 20-second breaks did not prevent symptoms during 40 minutes of demanding reading.