If you use iPhone in total darkness then even the lowest brightness is not dim enough and it kind of hurts your eyes. So how do your reduce brightness even further on the iPhone. Well there is only way to do – by jailbreaking it and installing Cydia on it because on Cydia, you will find a utility called Dimmer that allows you to dim the brightness to the point where the backlight is hardly being used.
Dimmer is designed with one purpose: to make your display darker. The backlight on your phone may work great for outside reading or when the lights are on, but when you’re lying in bed at nighttime, the darkest point can still be blinding. And it might even be keeping you up.
With Dimmer installed, you can turn your screen brightness down even further. From 100% to 30%, your normal backlight will control your brightness, and below 30%, Dimmer takes over and lets you virtually dim your screen beyond what your backlight can accomplish.
This application comes with a safety feature too. If your screen is pitch black, you can instantly raise the brightness to full by tapping the volume up button four times in fast succession, or through the use of an Activator event. An additional action is available to dim your screen: tap the volume down button four times in fast succession to lower your brightness.
Configuration options are available to adjust the various settings, including the dark point on the slider (how dark your display will go), the division between Dimmer and backlight operation, and the screen’s brightness when the Safety feature is activated.