In Pennsylvania, the law most closely related to Google Glass would be 75 Pa. C.S. 3704:
No person shall drive a vehicle when it is so loaded . . . as to obstruct the view of the driver to the front or sides of the vehicle or as to interfere with the driver's control over the driving mechanism of the vehicle[.]
Ultimately, in Pennsylvania it is hard to see how Google Glass obstructs the view of a driver to the extent required to receive a ticket. However, if an officer can prove that the user was viewing a video and driving while distracted, a careless driving ticket will likely be issued.
New Jersey has some of the toughest distracted driving laws in the country. Still, the laws directly refer only to phones and texting. The only statute that appears to relate to wearable technology such as Google Glass is NJ Stat. 39:3-74, which says:
No person shall drive any motor vehicle with any sign, poster, sticker or other non-transparent material upon the front windshield, wings, deflectors, side shields, corner lights adjoining windshield or front side windows of such vehicle[.]
No person shall drive any vehicle so constructed, equipped or loaded as to unduly interfere with the driver's vision to the front and to the sides.
Overall, drivers should exercise extreme caution when using new technologies such as Google Glass, particularly in states such as New Jersey which crack down hard on distracted driving. Even if the existing state laws do not directly address the technology, police officers and courts will likely try to expand the reach of the laws in order to hold a driver responsible.
* This analysis takes the law as it stands on November 8, 2013. Keep in mind that laws often change, particularly to address new technology. As always, drivers should exercise caution and pay full attention to the road, regardless of whether their technologies are legal.