Rotation of gameobject while dragging on the screen not working as expected in unity 4.6

I'm creating a 2d game in unity, similar to the game My Emma in the Playstore. In that my player characters eye balls (left and right) needs to be positioned and rotated when the player moves the fingers through the game scene. That is eyeballs should be positioned dynamically to the movement of the fingers through the device.

For this purpose, I have a bg game object, and in the game object I have attached a script called eyerotation.cs. There are 2 public game objects eyeleft and eyeright attached in the script. The two eyeball game objects are then attached to the eyerotation script in the bg game object using the Unity Editor.

To detect Dragging I have attached a Box collider 2d to the bg game object, and implemented IDragHandler and IEndDragHandler in the script.

The positions of the EyeRight Game Object before starting the game is (0.5, 0.9, 0.0) and EyeLeft is (-0.4, 0.9, 0.0). When I run the game, the eyes rotate based on the hand movement in the devices. But the problem is that it rotates based on an unknown pivot position, and not on the stationary eyeball position. Also the both eyeballs position is the same, during the rotation. I don't know why that's causing it.

is there anything that I had done wrong. Any help from anyone is easily appreciated. Thanks in advance.

This is the code of the EyeRoatation script file:

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine.EventSystems;
 
 public class EyeRotation : MonoBehaviour,IDragHandler,IEndDragHandler{
 
     public GameObject EyeLeft,EyeRight;
 
     private Vector3 LeftEyeStartPosition,RightEyeStartPosition;
     // Use this for initialization
     void Start () {
         LeftEyeStartPosition=EyeLeft.transform.localPosition;
         RightEyeStartPosition=EyeRight.transform.localPosition;
         Debug.Log ("Rght Eye Start Position "+RightEyeStartPosition);
         Debug.Log ("Left Eye Start Posiiton "+LeftEyeStartPosition);
     }
     
     // Update is called once per frame
     void Update () {
     
     }
 
     #region IDragHandler implementation
     public void OnDrag (PointerEventData eventData)
     {
         Vector3 CurrentScreenPosition=new Vector3((Input.mousePosition.x),(Input.mousePosition.y),1);
         Vector3 CurrentPosition=Camera.main.ScreenToWorldPoint(CurrentScreenPosition);
         
         Vector3 DifferenceLeft=CurrentPosition-LeftEyeStartPosition;
         Vector3 DifferenceRight=CurrentPosition-RightEyeStartPosition;
         EyeLeft.transform.localPosition=DifferenceLeft.normalized*0.5f;
         EyeRight.transform.localPosition=DifferenceRight.normalized*0.5f;
         //Debug.Log (EyeRight.transform.localPosition);
     }
     #endregion
 
     #region IEndDragHandler implementation
 
     public void OnEndDrag (PointerEventData eventData)
     {
         EyeLeft.transform.localPosition=LeftEyeStartPosition;
         EyeRight.transform.localPosition=RightEyeStartPosition;
     }
 
     #endregion
 }