Run script only when camera is looking away

Hi. I don't know if this is possible, but i'd really like to give it a try. So I've already added a working destroy script (below) on some objects in my game, I just would like an addition to the script so that it would only run if the camera was not facing the objects. Each object has it's own destroy script, with a timer. Thanks to anyone with any helpful material or scripts.

 #pragma strict
 
 var Seconds = 10; //this is different for each object
  
  function Update(){
      Destroy();
  }
  
  function Destroy(){
      yield WaitForSeconds(Seconds);
      Destroy(gameObject);
  }