(I'm not convinced that a nanosecond view of River in said eyepatch means that she's meant to turn into Eyepatch Lady. After all, we *already know* how River's story ends.)

Now that we've seen more than one person wearing the eyepatch, I think I know what it is. It shows a picture of a Silent at all times, so that the people wearing them can interact with them without memory problems. River's may or may not come with a mind control attachment.