Vertical line on a 46" Sony LCD

[IsthmusTV]

Greetings,

Lately I've been noticing a thin vertical line appearing at the edge of the display on my 4.5 year old Sony Bravia KDLW4600. It's about one or two pixels wide (it seems to vary) and runs the entire length of the panel, from top to bottom. It's only visible with certain picture content. It is not visible if the image is solid white or solid black. It seems to be most prominent when the image is mid brightness and a solid color, like blue. Any idea what's causing this? Is it likely to get worse? Right now, it's really not much of a problem particularly since it's only about 1/2" from the right edge of the display.

Thanks in advance,

Clark