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

This peer-reviewed study from SUNY College of Optometry tested whether the widely promoted "20-20-20 rule" — take a 20-second break every 20 minutes to look at something 20 feet away — actually reduces digital eye strain. The authors note there was little prior evidence supporting the rule despite its popularity.

Thirty young participants completed a 40-minute cognitively demanding reading task on a tablet under four conditions: 20-second breaks every 5, 10, 20, or 40 minutes (the last being effectively no break). Pre- and post-task symptom questionnaires, reading speed, and task accuracy were measured.

Post-task symptoms increased significantly across all conditions. However, scheduled breaks had no significant effect on reported symptoms (P = .70), reading speed (P = .93), or task accuracy (P = .55).

The authors conclude their results "do not support the proposal of using 20-second scheduled breaks as a therapeutic intervention for digital eye strain." Note the study tested only 20-second breaks at varying intervals on a single reading task — it does not rule out that longer breaks, different activities, or real-world use patterns might help.