Need help with 40" WEGA
 

I have the Sony kv40xbr700 and am having a problem. On each side of the screen there is a 4 inch section of the tube that is slightly darker than the center. This darker sections run down the entire length of the tube from top to bottom. It is especially noticeable when a white or a light blue sceen is displayed. It is also noticable if a sceen is panning across the screen. It is noticeable on all inputs. Anyone else experience this problem? Can it be repaired or does the tv have to go back. Any help would be greatly appriciated.