Pan Orthographic Camera

Hello, I have a 2d game. Its a side scroller. I need help trying to make my code only make it move to the side when im near the edge. not when I get side velocity which is everysecond

 var howfartomovescreen : int = 0;
 var velocity1 : Vector3 = Vector3.zero;
     if(Input.GetAxis("Mouse X") <  howfartomovescreen)
     {
     //Code for action on mouse moving left
         velocity1.x -=1;
     print("Mouse moved left");
     }
     if(Input.GetAxis("Mouse X") >  howfartomovescreen){
     //Code for action on mouse moving right
     velocity1.x +=1;
     print("Mouse moved right");
     }
 Camera.main.transform.Translate(velocity1);