What’s the 20-20-20 rule?
The 20-20-20 rule suggests that for every 20 minutes spent looking at a screen, you should try to take a 20-second break to look at something 20 feet away.
Unless you have a tape measure, you probably won’t be able to measure 20 feet accurately. However, being exact isn’t the key to the 20-20-20 rule for eyestrain.
The main idea is that you should try to focus on something far away from you. Consider looking out a window at an object that seems far away, like a tree or a building across the street.
If you work in a small space, just look out the window into the distance.