Dark shadow-like vertical streaks thru LCD screen (Sharp)

Our Sharp LCD tv (about 45") is about 3 years old and has gotten dark, vertical streaks on right and left sides of the screen. They are more obvious when the screen is bright of course, very annoying. (We had a smaller Sharp tv that did the same thing and the streak just kept getting darker and wider. Eventually the tv just went out and would no longer stay on.)

What can we do about the streaks?

Thanks!