There are 3 different modes as:
20-20-20: When you have spent 20 min in front of a computer, a 20 sec break is signalized. In this break, close your eyes or focus the eyes on an object 20 feet (6 meters) away.
60-5: When you have spent an hour in front of a computer, a 5 min break is signalized. You’ll feel signal with a sound alarm and screen blackout.
Custom: In this mode you can define your break’s frequency and length.
To get started, simply visit Protectyourvision.org website and click “Start EVO”. Once clicked, you’ll be asked to select a mode (20-20-20, 60-5, custom). You can switch on/off sound alarm and screen blackout, in each mode. In the break, EVO will recommend you to do some eyes exercise. This will prevent your eyes from optical system abnormalities.