Screen Filter is described as 'Applies a shade that acts as a dimmer to ensure your eyes don't hurt. Far more powerful than Android's built-in brightness setting. Great for low-light gaming, web browsing, and eBook reading. It even saves battery life for AMOLED displays!'. There are more than 25 alternatives to Screen Filter for a variety of platforms, including Windows, Mac, Android, Linux and Android Tablet. The best alternative is f.lux, which is free. Other great apps like Screen Filter are Redshift (Free, Open Source), LightBulb (Free, Open Source), Red Moon (Free, Open Source) and RedshiftGUI (Free, Open Source).