Google Glass was developed by Google X and uses optical head-mounted display (OHMD).
The display is translucent, so it does not hinder you doing daily routines.
The glass can be controlled by a touchpad integrated into the glasses frame or by voice commands.
Want to see how Google Glass actually feels?
How to control Google Glass?
Interacting with Glass is a unique experience that can range from head gestures to touch gestures that allow you to use Glass but stay in the moment with others with minimal distraction.
You can use touch gestures by tapping and sliding your finger on the touchpad located on the right side of the device near your temple.
Activate Glass: Tap the touchpad to turn the display on.
Select an item: Tap the touchpad to select a card or expand a bundle.
Back and display off: Swipe down from the Home screen to turn the display off. Swiping down also acts as your back button.