The ability
to move the lenses of the glasses back and forth, thus changing their location relative to the screen and the user's eyes. The specific meaning of this function can be different: it can adjust the angle of view (so that the screen fits completely in the field of view and at the same time is not too small), play the role of diopter correction (which is important for users who wear glasses) or focus, change the setting interpupillary distance (see below), etc. These nuances should be clarified separately. However, anyway, this function will not be superfluous — it makes it easier to adjust the glasses to the personal characteristics of the user.
The presence of a
controller — an additional control device — is included in the delivery of glasses.
The design and functionality of such an accessory may be different. So, the most popular option is specialized game controllers with a characteristic look — a handle with an analogue lever and buttons. There can be two such handles at once, under both hands; and in some models they are also used to control gestures. The movement of the hands can be tracked both by sensors in the controllers themselves and by cameras on the glasses. There are also simpler solutions — for example, portable gamepads or remote controls for controlling video playback.