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American Optometric Association:

The average American worker spends seven hours a day on the computer either in the office or working from home. To help alleviate digital eyestrain, follow the 20-20-20 rule; take a 20-second break to view something 20 feet away every 20 minutes.

Canadian Association of Optometrists:

Every 20 minutes, take a 20-second break and focus your eyes on something at least 20 feet away.

(20 feet = 6.096 m)

What evidence is there to support this 20-20-20 rule/recommendation?


Related questions:

Where did this rule come from? (It sounds like some folk remedy invented by some layperson.)

Is 20 feet = 6.096 m optimal? Why not 10 or 40 or 200 feet or 2000 feet? (Similar questions for the other two variables of frequency and duration of breaks.)

Why can't we just close our eyes periodically to reduce eye strain?

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    Is anyone making the claim that this regimen is optimal? Probably not. Round numbers, memorable phrase, a distance that you'd likely find available in an office environment: practicality is important, too, and elaborate studies to follow people over a long time spread over multiple factorial groups to cover the whole parameter space...not practical.
    – Bryan Krause
    Aug 14, 2023 at 2:03

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6 m/20 feet is about the infinity distance for the human eye - actual infinity is infinity, but the accommodation between 6 m and infinity is minimal. this is known as the Far Point.

The actual best practice will be to focus on things further than 6 m, as in the Canadian quote you provided, so as to provide an infinity point - basically any distance 6 m or greater works. If you follow the Canadian link you provided, you will find references to support the

But I agree with the comment from Bryan Krause - keep it simple and memorable and it is more likely to get complied with. Indeed I found an Optometry Times article1 where the author tracked down the originator of the phrase, who was simply wanting a simple easy phrase to remember:

“In speaking to corporate workers, I needed a way to get them to take breaks while at the same time allowing them to accomplish their work,” Dr. Anshel says. “The general ‘rule’ at the time was to take a 15-minute break every two hours. Yet most people with visual stress noticed problems earlier than two hours into their workdays.”

Thus, the 20-20-20 Rule was born.

Dr. Anshel says The Rule gives computer users a quick and easy “tag” to remember when using their computers.

“The tag came from TV and radio interviews that time,” he says. “The interviewers asked what people can do about computer eyestrain, so I honed this into something easy to remember. I started with the ‘3B’ approach: blink, breathe, and break. Then the 20-20-20 Rule came out of the ‘break’ recommendation.”

The basis behind the 20-20-20 Rule, according to Dr. Anshel, comes from studies that found benefits of shorter, more frequent breaks for musculoskeletal disorders.10-13 He adapted the information to the visual system.

Having said that, there seems to be a lack of actual studies that support the use of this rule as being better than no intervention. One small study2 published this year suggested no impact, a did a larger study3, though one paper in African Vision and Eye Health4 suggested a positive impact.

Refs:

  1. Deconstructing the 20-20-20 Rule for digital eye strain. Optometry Times. Feb 22, 2018. https://www.optometrytimes.com/view/deconstructing-20-20-20-rule-digital-eye-strain. Accessed August 2023. Brian Chou.

  2. Johnson S, Rosenfield M. 20-20-20 Rule: Are These Numbers Justified? Optom Vis Sci. 2023 Jan 1;100(1):52-56. doi: https://doi.org/10.1097/OPX.0000000000001971. Epub 2022 Dec 6. PMID: 36473088.

  3. Datta S, Sehgal S, Bhattacharya B, Satgunam PN. The 20/20/20 rule: Practicing pattern and associations with asthenopic symptoms. Indian J Ophthalmol. 2023 May;71(5):2071-2075. doi: https://doi.org/10.4103/ijo.IJO_2056_22. PMID: 37203083; PMCID: PMC10391416.

  4. Alghamdi, W., & Alrasheed, S. (2020). Impact of an educational intervention using the 20/20/20 rule on Computer Vision Syndrome. African Vision and Eye Health, 79(1), 6 pages. doi:https://doi.org/10.4102/aveh.v79i1.554

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