code: function(oldData){
  
              var object3D = this.el.object3D.children[0];
              var data = this.data;
  
              if(data.eye === "both"){
                object3D.layers.set(0);
              }
              else{
                object3D.layers.set(data.eye === 'left' ? 1:2);
              }
  
         }
docs: On element update, put in the right layer, 0:both, 1:left, 2:right (spheres or not)