The 20-20-20 rule, explained

Every 20 minutes, look at something 20 feet away for 20 seconds. Here’s why it works.

When you look at something close, the small muscles that focus your eyes stay contracted. Hours of that is a big part of why your eyes feel tired after a long day at a screen.

The 20-20-20 rule, widely recommended by eye-care professionals, gives those muscles a regular rest: every 20 minutes, look at something about 20 feet (6 metres) away for at least 20 seconds.

The hard part isn’t the rule, it’s remembering. That’s the whole job of a break reminder: it keeps count so you don’t have to, and holds off while you’re on a call.