Twilight: filter the blue light of your device and sleep better

Twilight Health and fitness. Android (V2.2 or above). Free; ‘Pro’ version available for €1.99/£1.99/US$1.99. The Twilight app was created to help people mitigate sleep perturbations arising from the usage of self-illuminating electronic devices (eg, mobile phones and tablets) prior to sleeping.1 Blue light in the range of wavelengths 446–477 nm has been identified as the most potent light stimulus that suppresses melatonin production,2 a hormone that plays a major role in the regulation of sleep and wake cycles.3 Accordingly, Twilight filters the blue light emitted from mobile devices and protects the eyes with a soft red pellicle, potentially helping the user to fall asleep earlier and sleep better.1 ,4 ,5 On the basis of the user's local geographic coordinates, which are taken by …