At 97, having blurry vision seems very normal to me. I doubt there's anything to be done about it. Eye exams require special equipment. Not sure if house calls are possible.
Stroke and blood pressure issues are among other non-eye related reasons one can have blurred vision. These should be discounted by her regular doctor if possible.
Eye doctors can give an exam in the home. They do it in NHs all the time. Call a local Nursing home and ask if thet can give u the name of the doctor associated with them.