Closing eyes with dementia?

I've read that sometimes vision problems happen as they continue to lose brain cells, I also think that the input from outside world can become too overwhelming in the late stage so closing their eyes allows them to shut it out.

My Mom would do this. I would even tell her to open her eyes and she wouldn't. Her last two weeks she did it and never opened them again. She was responsive, just wouldn't open her eyes. The weird thing was she made more sense with her eyes closed than with them open.