This guy who gets headaches is a sad excuse for a human. He probably gets headaches watching TV in a dark room, too. And probably gets car sick on 15 minute drives. And has allergies that keep him indoors all spring. What a loser. Using Glass 8 hours straight each day? For one, the battery only lasts about 3 hours during fully active use. And for another point, staring at a smart phone or a tablet for EIGHT straight hours will cause a headache, too. Loser.