No therapy is available to prevent, slow the progression of, or reverse the degenerative changes of PRD/PRA.
Care consists of providing a consistent and safe environment for pets with vision loss. Considerations include:
Preventative Care for Progressive Retinal Degeneration in Dogs
No preventive care is available for an individual because PRA is genetic. Do not breed affected animals.
Genetic testing is available for about 15 breeds of dogs affected with PRA. Testing performed on a blood sample can identify which dogs are affected and which are carriers of the disease. This information can then be used by breeders to decide which dogs may or may not be used for breeding. In addition, dogs can be examined on a yearly basis by a veterinary ophthalmologist and certified to be clinically free of the disease. The certification is valid for a period of one year from the time of examination.
Veterinary care often includes diagnostic tests to confirm the present of PRD and to exclude other diseases. Tests may include:
Diagnosis In-depth for Dogs with Progressive Retinal Degeneration
– Tests to evaluate vision, such as observing the dog navigate an obstacle course in both bright and dim light, and certain neurologic reflex testing
– Pupillary light reflex testing
– A Schirmer tear test and fluorescein staining of the cornea
– Tonometry to measure the pressure within the eye
– Specialized examination of the front chamber of the eye, the iris and lens, the vitreous and the retina.
– A complete blood count (CBC) and serum blood tests
– Blood tests for the tick borne diseases (Lyme disease, ehrlichiosis, etc.), fungal diseases and toxoplasmosis
– A measurement of systemic arterial blood pressure to rule out high blood pressure
– Possibly immune tests
– Possibly chest and abdominal X-rays
– Ultrasonography of the structures behind the eye
– CT scan or MRI of the brain and vision pathways leading to the brain
– Cerebral spinal fluid tap to evaluate the fluid around the brain
Treatment In-depth for Progressive Retinal Degeneration in Dogs
There is no treatment for PRD. Most forms of the disease are inherited as a simple autosomal recessive trait, which allows many dogs to be silent carriers of the disease. This inheritance pattern, combined with the fact that many dogs do not show signs until after they are older, make the disease very difficult to eradicate in some breeds of dogs.
For the 15 breeds of dogs in which genetic testing has been developed (www.optigen.com), blood testing of potential breeding dogs is the best way to identify both carriers and dogs that will show clinical signs. For all other breeds, electroretinography can be performed as a screening tool to detect the disease prior to the onset of clinical signs and retinal abnormalities.
The most common screening test used for PRD/PRA in breeding dogs is the annual examination of their eyes by a veterinary ophthalmologist. Results of this exam are then forwarded to the Canine Eye Registry Foundation (CERF, www.vmdb.org), an organization that keeps data on the eyes of many purebred dogs in the United States. If the dog is found to be free of inherited eye disease, then it is issued a clearance number by CERF that is good for one year
As more CERF examinations are performed and as more genetic tests are developed, hopefully breeders will be able to avoid using affected dogs and carrier dogs in their breeding programs and the incidence of PRA will decrease with time.