The Verge:

The glasses company is cleverly using the iPhone’s camera to take maps of people’s faces, and use that data to recommend styles of glasses that will best fit your face. It’s a step beyond the digital try on system the company has previously offered, where it would try to place a virtual pair of glasses on a picture to let you see how it looks.

Sadly, I’m in the market for glasses but dread going in to a store to try them on. This might resolve that pain point for me.