Wink is an exploratory feature allowing you to take a picture simply by winking. It's the fastest way to take a picture with Glass and particularly helpful when your hands are full.
This Settings card lets you turn Wink on and calibrate it to your eye. Tap to turn it on. Glass will ask you to wink twice. Make sure that you look at the display while winking. Once that's done, any time that you intentionally wink (not blink), Glass will take a picture.
Wink doesn't work on everyone. If Wink stops working, return to this card to recalibrate Wink. For more troubleshooting steps, visit this Wink article.