Abstract: The present invention relates to a wearable electronic device, a viewing system comprising the wearable electronic device, a display device and methods for operating a wearable electronic device and a viewing system, respectively, wherein the wearable electronic device comprises a pair of glasses which can be controlled to change their optical state in a way to allow other and more flexible use of the equipment. The wearable electronic device for watching images comprises a left glass and a right glass which are adapted to change between a dark state and a transparent state of the glass and a controller operable to control the state of the glasses synchronous with a display of a plurality of images per second by a display device so that said left glass and said right glass are both in a dark state at the same time for a specific displayed image.