The disease involves all three layers of the posterior eyeball. Mild SES can result in a blind spot, while severe cases will lead to complete blindness. Breeding stock should be tested yearly. Affected dogs often begin with night vision problems, progressing to loss of day vision and total blindness. Currently, there is no treatment for either disease.
Prevention is through the breeding of clear stock.
Request that your puppy have an eye exam by a certified ophthalmologist before you take it home. Also request evidence that the puppy's parents have been examined within the last year. To find out about the possibility of your puppy developing PRA as an adult, ask if the parents and grandparents of your puppy were tested yearly, or at least prior to each breeding. Research is searching for genetic markers. Hopefully, we will one day have a DNA test for this disease.