For an 11 year old monitor, color imbalance is to be expected. I think the right side is yogure. No fixes. Time to replace it.
I have something like discoloration at the right side of the screen (U2312HM) and something like "net" compared to the right side. Did the screen gone bad? Is there any fix? Its a little difficult to capture in the video but i believe its visible. Here is the link:  [URL] 
U2312HM, bad colors and "net" at one side