Rat eye diseases in female dogs/cats

Question
I have pocket minitature doberman pincher that is 4 years old and she is currently going blind. What this has to do with rats, even I didn't realize until aclient of mine mentioned that the open park ravine, next to our home has an increased prevalence of wild rats. I know this is not necessarily the same as the kind of rats that you keep aspets, but the solution, I believe is within our grasp. The first Vet said cataracts (which is congenital), the second said it isalmost impossible as she is only 4 years old.

In the last 2 years we have had our cats bring many victims (rats) onto our property, but never ate them. two of our female pets (my parents female cat of many years old) and our own female cat of 4 years old, developed a hazy eye (or both) after we moved here from Randburg. Now our female dog, has the same hazyness, which has gone from a tinge to her now not being able to see at all in just over six months. Can anyone help, advise, suggest, provide links or give some keywords I can search as I am going to see the specialist at one o'clock today!!! Please  

Answer
I have never heard of rats passing anything that could be linked to blindness. I would consider another source, possibly the water....maybe keep the pets indoors so they are not exposed to any possible pathogens that may be lurking outside.  It could be anything to be honest.