Your iPhone and iPad had been designed and manufactured for daytime use actually. For this reason when you start using your iPhone or iPad at night or in a dark environment, you feel you get blinded by your device's screen. Thing drives to this reflex is blue light which is also very harmful for you eyes, and can causes sleep disorders.
Unblue is the very first app minimises effects of blue light on the App Store which helps you to protect your eyes while browsing the Web and prevents sleep disorders.
P.S. We will continue to develop Unblue with new features. We look forward for your feedbacks!