Pooping on the living room floor

I came out this morning to find that my sweet old girl had pooped on the living room floor. She is border collie | retriever | something else mix and about 14 years old now. I've had her since she was 8 and she has only done this about 3 times in the last few months.

I've noticed also that she is pooping on the patio instead of out in the yard also. She does have cataracts so I know her vision is definitely impaired. Could it be that it's just more effort to go outside at times with her age or her vision is affecting her? Otherwise, all the rest of the time she goes out the dog door and right to the yard and has always been very good about going outside. She has no problem going out the dog door also. The yard is fully fenced so it's not a matter of other dogs being in the yard.

Any input is helpful. Here's my gorgeous girl below.

http://i239.photobucket.com/albums/f...ickeywalk1.jpg

Has she been to the vet to rule out a medical reason? And did you clean the spots in the living room with an enzymatic cleaner so it gets rid of the things we cannot smell, but that tell dogs "good spot here!" And does the poop look formal?

She is due for her annual checkup but was just in the vets for emergency care in October as she had vestibular disease and got throughly checked out then.

As far as the spot on the floor, you're question just gave me an idea. I got locked out one night and had to go through the backyard in the dark to get to the spare key. I did step in poop w/o knowing then saw "poop tracks" through the living room. I cleaned those but maybe some smell still lingers in those spots. I'll work on that part.

I'm still wondering though why she's pooping on the patio. One of my cats absolutely refuses to poop in the yard and dig a hole like most cats. I put a cat box out there but she won't use it either. Maybe Mickey is seeing that the cat is pooping there so she is too.