The 20-20-20 Rule for Eye Strain

The 20-20-20 rule is a guideline for reducing digital eye strain. Every 20 minutes, take a 20-second break and focus your eyes on something at least 20 feet (about 6 meters) away. It was popularized by California optometrist Jeffrey Anshel and is recommended by the American Academy of Ophthalmology and the American Optometric Association.

When you stare at a screen, your ciliary muscles — the tiny muscles that control your eye's lens — contract to maintain near focus. After 20 minutes, these muscles begin to fatigue. Looking at something 20 feet away relaxes them back to their resting state. Twenty seconds is the approximate time needed for full relaxation. The rule also naturally triggers blinking, which re-moisturizes your eyes.

About 6 meters. Roughly the distance across a large room, the length of a standard parking space, or the distance from your desk to a window at the end of a hallway. You don't need to be exact — anything significantly farther than your screen works.

Multiple studies support the principle behind it. Research published in the Nepal Journal of Ophthalmology found that the 20-20-20 rule significantly reduces symptoms of computer vision syndrome. The American Academy of Ophthalmology recommends it as a practical prevention strategy. While some researchers note that longer or more frequent breaks may provide additional benefit, the 20-20-20 rule is the most widely endorsed starting point.

That's what this timer is for. Most people know the rule but don't follow it because they get absorbed in their work. NowDo20 automates the reminder so you don't have to rely on memory. Press start once and the timer cycles automatically — work session, eye break, work session, eye break.