- Every 20 minutes
- Look at something 20 feet away (6 meters)
- For at least 20 Seconds
The 20-20-20 rule is designed to be an easy to remember caution about doing too much near work and to give your eyes a break from eye strain regularly. This rule is supported by conventional optometry and is a start towards the EM method.
In some countries, this may be known as the 10-10-10 rule which is similar, but goes as follows:
- Every 10 minutes
- Look at something 10 meters away
- For at least 10 seconds
Endmyopia recommends even more breaks.
- Every 20 minutes, take a 5 minute break.
- Every 3 hours, take the longest break you can (half hour to hour) 
- Take your break outside. 
- As you develop Strain Awareness you can customize your break schedule to your needs.