What is passthrough mode on Gear VR, and why should I care?
(Android Central)

Passthrough mode on Gear VR lets you see the world around you through a camera Generally the point of putting on a VR headset like Gear VR is to leave the real world behind temporarily. However, there is a way to see what is going on around you quickly, even if you are wearing your Gear VR. Passthrough mode lets you see your surroundings from the view of the camera on your phone - basically through a grainy square. It`s not something you should need to do often, but you can definitely use it. Whether you want to use it is what becomes the more pressing question to ask. Read more at VRHeads.com ...