I created this application because I was suffering from CVS (Computer vision syndrome), basically it has two options hardcore or core mode. Hardcore mode locks you out of your computer until you've spent twenty seconds looking away (Obviously if you actually look away or just wait 20 seconds is down to you), Core just reminds you that you need to. Download here

Features:

Two levels of reminders
Counter so you know when it's been twenty seconds
Hidden application only shows when you need to look away