Google Glass is getting an update to XE 17.3, but it is not released yet. At least not right now. If you want, you can download the update manually and slap it on Glass, but if you wait, the update probably will be received by your Glass in the next few weeks.
The update makes some bug-fixes here and there, but what is significant is the inclusion of a feature called “Notification-Glance”. If this feature is enabled, you can trigger Glass by merely moving your eyes towards the screen in response to a Notification and Glass will show you your Notification. This is more convenient that actually having to tilt your head to view your notifications.
This currently only applies to notifications and in later updates, the Glance feature may be used to do even more things (Making taking Discreet shots even easier). Also, if you turn your eyes towards the “screen” when there was no recent notification, Glass will give no response, i.e the screen will not turn on.
If you are feeling adventurous and want to download the update before Google pushes it Over-The-Air, then head over to XDA-Developers which has a copy of the Update. Android Police has the instructions.