This is considered hereditary. In some cases it is not.
The non hereditary term for this is Corneal Degeneration.
A friend’s dog was diagnosed with corneal degeneration and the specialist believes it is from too much fat in the diet. Changing the dog food to a lower fat content can reverse the degeneration and you may see the spots on the eyes shrinking or completely disappearing. There should be a recheck a couple of months after changing dog food.
Corneal Dystrophy can also be caused by an infection or: