This is an app which works like one of those old screen filters that old screens had to carry: it dims the backlight of your device beyond the normal settings. This reduces eye strain while reading at night as it lowers the contrast between the screen and your surroundings. Particularly for the Super AMOLED screen of the Galaxy S and Nexus S, it is a must-buy for night reading.
http://www.theandroidsoul.com/screen...roid-app-free/