E1910H screen appears grainy/flickering on color gradients

I have had this monitor for a little over 3 years, so it may simply be that it's on its last legs, but if it is at all possible to fix it, I'd love to get any advice.

Until very recently, the monitor was working fine with no issues. I made no major changes to the hardware or software configuration, and I haven't changed the monitor resolution or settings. However, when I turned it on this morning, I discovered that areas of my screen have a grainy, discolored, flickering appearance. The screen functions alright for displaying solid colors and text, but the flickering effect at the edges of various windows is extremely obnoxious.

I did a little searching on this problem and was able to find information on running a Built In Diagnostic on the monitor, so I tried that. Colors display properly, but on the solid black screen there was a lot of low-level grainy flickering across the whole screen. I also used the PC Diagnostics on the Dell support page, but it came up with nothing useful.

While running the PC Diagnostics, there was a popup in my browser window that darkened the rest of the window, and I noticed that in that dark area the effect was especially pronounced, so I took a picture with my phone. Here is the image resized, as well as a link to the full-size image. Hopefully you can see the effect in the image.