Changing to an Event button Button is directed?

I made an application that uses a Samsung S6 and the Gear VR.

I start the application on a Standby Level so that the viewer can put the glasses and then press the main button to start the presentation.

But I realized that when the viewer is putting the glasses, he always press the button unintentionally. At Standby Level I use a transparent widget that makes a pause in the presentation and is waiting for a button event to start application again, how can change to the back button to this event?

Thanks and sorry my English.