Shes starting to use the main bed as a litterbox!!

I put fresh litter in the box and put towels on a plastic backed table cover so she wont ruin the mattress.

I think its the fact that her vision is slowly going, and the trip to the litter box is too arduous.

I love My Princess and would hate to have to confine her to the bathroom.

Any ideas and thoughts please.
I LOVE MY PRINCESS!!!!!