When it is dark, your eyes dilate (your pupils, the black spot of the eye gets larger) to allow in more light in to see better. White light is the highest of all energy light, and causes your pupils to contract (get smaller) thus ruining your night vision. Red light is of the lowest energy light your eyes can see, and causes your eyes to contract LESS than white light (or any other color). By default when you load this app, it loads red light at 50% intensity, so while you are looking at the screen your eyes can continue to dilate. You can easily and quickly turn up the intensity of the red light with the slider for more light, and face the screen at what you need to see, illuminating your path while maintaining your night vision. Even white light bouncing off your path can ruin your night vision.
If you need that extra amount of light, you quickly swap to white light with the switch button.
Also, this light uses the entire screen space to produce light, not just a small area or image of a light blub like most other apps, allowing to produce maximum light.
Features: Very small file size, extremely fast loading, easy to use. No advertisements, 100% free!