If you’re stuck staring at a computer screen all day, you need to regularly rest your eyes. The American Optometric Association recommends the 20-20-20 rule: first set your phone to buzz every 20 minutes. When the alarm rings, focus on something that’s about 20 feet away for 20 seconds; this will help your eye muscles relax. And you’ll have an excuse for staring mindlessly into the distance. That’s not daydreaming! It’s preventative medicine.