Methods and systems disclosed herein relate to a shading function or device for use with a head-mountable device. An example method could include determining, from a touch-sensitive surface of the head-mountable device, a swipe interaction. The head-mountable device could include at least one optical element. The at least one optical element could be configured to transmit outside light from an environment of the head-mountable device. The method could further include causing at least one property of the at least one portion of the at least one optical element to be controlled based on the swipe interaction. The at least one property could include a transmittance of the at least one optical element. In one implementation, the optical element could be mounted a substantially distal surface of a see-through display.