20-20-20 eye break

Every 20 minutes, look at something 20 feet away for 20 seconds to relieve the ciliary muscle fatigue that causes digital eye strain.

Why it works

The ciliary muscle inside the eye contracts to focus on close objects and relaxes for distance. Sustained screen use keeps it in a near-constant contracted state, causing ciliary muscle fatigue — experienced as eye strain, blurry vision, and headaches. The 20-20-20 rule forces a relaxation of the ciliary muscle by shifting to distance focus, reducing accumulated fatigue before it reaches the threshold of discomfort. It also prompts blink rate recovery — blink rate falls during screen use, increasing dry eye.

How to do it

1. Set a 20-minute timer during screen work.
2. At the alarm, look at an object approximately 20 feet (6 meters) away.
3. Hold soft focus for 20 seconds — resist the urge to scan or read.
4. Blink deliberately 10–15 times during this period to recoat the eye surface.

Evidence

The 20-20-20 rule is recommended by ophthalmology organizations for digital eye strain. The underlying mechanism (accommodative fatigue and reduced blink rate with screen use) is well established; direct RCT evidence on the specific 20-20-20 interval is limited. (mechanistic)

The "20-20-20" framing is a clinical heuristic rather than a researched interval; any regular distance-focus break likely provides similar benefit.

Common mistake

Breaking at 20 minutes but looking at a phone (still a near-focus object) rather than a genuinely distant point, which does not release the ciliary contraction.