memory issues

They are childlike when they get like this, aren't they. Would you argue with a child? You'd explain once, and then say,
"This is the way it is. The discussion is over." It's been working
for me!

My mother-in-law is convinced the eye glasses she's wearing are NOT hers. It has been verified by different doctors etc. that they are indeed hers. Do we just get different glasses? Do I keep trying to explain it to her, which is like banging my head up against a wall? She is in this memory loop thing that is driving us crazy. I have tried to distract her onto something else, but she keeps coming back to it. What do people do to deal with the fact that the person with dementia can no longer be logical and think rationally? It goes against the grain to just go along with her, placating her. But is that what needs to be done at this point? I do hope someone has an answer, or at least a suggestion we haven't thought of yet. Thanks
Nancy