Architecture and designs of wearable devices for displaying images or videos are described. According to one aspect of the present invention, a display device is made in form of a pair of glasses and includes a minimum number of parts to reduce the complexity and weight thereof. Image data along with control signals (including instruction data) is optically transported by an active optical cable all the way through a temple to a microdisplay embedded and deposed near one end of the temple of the glasses. Optical images produced by the microdisplay are captured and projected into an integrated lens or an added light waveguide on a lens for displaying the optical images before the eyes of a wearer.