Vision Defense is described as 'The Vision Defense Software provides you with reminder prompts to briefly look away from the screen at specific time intervals that you select. You may choose to display the prompts in any one of the four corners of your screen'. There are more than 25 alternatives to Vision Defense for a variety of platforms, including Windows, Mac, Linux, BSD and PortableApps.com. The best alternative is stretchly, which is both free and Open Source. Other great apps like Vision Defense are Workrave, RSIBreak, Time Out and Eyes Relax.
Workrave is a program that assists in the recovery and prevention of Repetitive Strain Injury (RSI). The program frequently alerts you to take micro-pauses, rest breaks and restricts you to your daily limit.
RSIBreak is a small utility to remind you to take regular short breaks. Repetitive Strain Injury is an illness which can occur as a result of continuous work with a mouse and keyboard. The risk of suffering injury increases the longer users work without breaks.
It’s an utility that helps avoiding eyes-related problems when working at a computer for several hours. Concentrating your eyesight on a computer screen can cause an eye strain. You can prevent this by taking regular breaks during the work and look at distant objects.
Save yourself from RSI and eye-strain
BreakTimer allows you to set up customizable breaks and will remind you to take them.
BreakTimer is free and open source and available for Windows, macOS and Linux.
Iris is software which makes monitors healthy for the eyes. With iris you can reduce the blue light emitted from your screen for better sleep, reduce the brightness of your screen without PWM and avoid eye pain.