There is a rule created by Doctors called 20-20-20, this is advisable that after every 20 minutes of computer use you should should take rest at least 20 seconds and at the same time see (focus) on an object at a distance of 20 feet (something like 6 meters).
So I want to share with you 20 Cubed , a simple browser extension for Chrome , Which remind you that your eyes should take rest every twenty minutes for 20 seconds. These few seconds we should use our eyes to relax, 20 Cubed looks to lessen the damage by reminding you to look away every 20 minutes.
By taking time to focus on something a bit further away than your computer screen you are allowing your eyes to relax. This extension has not be scientifically proven to work and it cannot promise to prevent eye damage caused by long-term computer usage. It only tries to remind computer users to focus on something else, if only for a short while. 20 Cubed can be downloaded from the Chrome Web Store .
Download | 20 Cubed
Via | Lifehacker