Old dog health

Hello everyone, I was just hoping for some tips to increase my dogs health. She's in great condition for her age, but I want the best for my old girl. (:

Information-
Name: Bessie
Breed: border collie/terrier mix
Age: 14
Gender: female
Exercised:Walked once every few days. We can't do more because she had surgery when younger and a lot of exercising makes her limp. She does walk around the house and stay active though.
Dog food brand: Iams
Spayed: Yes
Health problems: some cataracts. Again, her back leg isn't as strong as the rest due to her surgery.

The surgery was when she leapt for a frisbee and landed wrong. :/

Does anyone have extra health ideas for her? Dog food, exercise, etc. thanks!