Raw capture — raw/20-20-20-rule-digital-eye-strain.md

url: https://pubmed.ncbi.nlm.nih.gov/36473088/ title: "20-20-20 Rule: Are These Numbers Justified?" author: Sophia Johnson, Mark Rosenfield date_fetched: 2026-07-18 date_published: 2023-01-01 journal: Optometry and Vision Science volume: 100 issue: 1 pages: 52-56 doi: 10.1097/OPX.0000000000001971 pmid: 36473088

20-20-20 Rule: Are These Numbers Justified?

Authors: Sophia Johnson and Mark Rosenfield

Affiliation: SUNY College of Optometry, New York, New York

Journal: Optometry and Vision Science (Optom Vis Sci), Vol. 100, No. 1, pp. 52–56, January 2023. Epub December 6, 2022.

DOI: 10.1097/OPX.0000000000001971

Significance

Digital device use has "increased substantially in recent years across all age groups" for both work and leisure, with corresponding increases in digital eye strain. A range of management options exist, including "optical, medical, and ergonomic interventions."

Purpose

The widely promoted "20-20-20 rule" advises taking a break every 20 minutes to look at something at least 20 feet away for 20 seconds. The authors note there is "relatively little peer-reviewed evidence to support this rule." This study aimed to test whether scheduled breaks reduce the adverse effects of device use.

Methods

• Subjects: 30 young participants
• Task: A 40-minute cognitively demanding reading task on a tablet, requiring reading random words and identifying those starting with a specific letter chosen by the experimenter
• Conditions: The task was performed on four separate occasions with 20-second breaks at different intervals: every 5, 10, 20, or 40 minutes (the 40-minute condition was effectively no break)
• Measurements: Pre- and post-task questionnaires about ocular and visual symptoms; reading speed and task accuracy were also quantified

Results

• A "significant increase in post-task symptoms" compared to pre-task values was found across all four trials (P < .001)
• However, scheduled breaks had no significant effect on:
• Reported symptoms (P = .70)
• Reading speed (P = .93)
• Task accuracy (P = .55)

Conclusions

The authors state: "These results do not support the proposal of using 20-second scheduled breaks as a therapeutic intervention for digital eye strain."

Conflict of Interest: None reported.

MeSH Terms

Asthenopia, Humans, Reading

References

27 sources cited, including foundational work by Rosenfield (2011) on Computer Vision Syndrome, research on screen time during COVID-19, and studies on myopia progression and digital eye strain during the pandemic.