New research published in Optometry and Vision Science suggests that taking longer breaks or with different frequencies may be the answer to minimizing digital eye strain —a major contrast to the long-held 20-20-20 rule.
Remind me about the 20-20-20-rule.
The practice recommends for a person working on any digital device to stare at an object at least 20 feet away for at least 20 seconds, every 20 minutes. The thought is that, by taking frequent breaks, it could reduce digital eye strain symptoms. (via)
Talk about the research.
Investigators enrolled 30 participants (25 female; mean age of 24.1) who attended four sessions that were each separated by a 24-hour period, within a 4-week time period. Sessions included a 40-minute reading task that participants completed using an iPad tablet computer; each task consisted of reading out loud and identifying words beginning with specific letters.
Participants were permitted to take breaks during each session by looking out the window at a distant target for 20 seconds. Breaks could be taken every 5, 10, and 10 minutes, respectively, for the first three sessions. No breaks were allowed during the last 40-minute session. (via)
How were participants tracked?
Participants completed a questionnaire about their ocular and visual symptoms both before and after each session. Ratings were based on a scale of 0 (none) to 10 (very severe).
What were the findings?
Investigators found that interval variation between breaks did not result in a significant change in reading speed (P = .93), reading accuracy (P = .55) and reported symptoms (P = .70). However, they did observe a significant increase in post-task symptoms (eye strain and blurred vision) for all four trials (P <.001).
Take home.
The authors concluded that the findings provide no support for the 20-20-20 rule as an effective therapeutic prevention for digital eye strain. Further, they expressed no surprise, since there appears to be little or no existing evidence to support the use of the 20-20-20 rule to minimize symptoms.
They cautioned that these findings should not be interpreted as evidence that taking breaks can not be helpful in reducing digital eye strain.
The authors recommended additional research be conducted for assessing the effects of longer breaks.