Sudden Acquired Retinal Degeneration Syndrome (SARDS) is characterized by sudden vision loss in the dog. This disease affects the retina, which is in the back of the eye. For an unknown reason, SARDS patients suddenly loose retinal function and develop subsequent degeneration or atrophy of the retina. In addition to sudden loss of vision, many owners notice dilated or enlarged pupils.
This syndrome often occurs in adult dogs of various ages, usually ranging from six to 14 years old. No one breed is predisposed or more susceptible than another. Often affected animals are in good health, but some dogs may have a recent history of obesity, lethargy, increased appetite, increased consumption of water and/or increased urination. Blood work is recommended to rule out any systemic problems, and if affected dogs have systemic problems, an internal medicine consultation may be recommended. The etiology, or underlying cause, of SARDS is currently unknown; however, research is being conducted to look for the primary cause. Possible theories for this syndrome include endocrine disorders, like Cushing’s disease, autoimmune disease, toxicity, neoplasia, etc.
In all patients with acute vision loss, an electroretinogram (ERG) is recommended to assess retinal function and definitively diagnose the disease process. This test helps differentiate SARDS from other causes of acute blindness such as optic neuritis, which may require further work up and treatment. An ERG involves simply putting a specialized contact lens on the eyes of an awake or lightly sedated dog. A series of lights are flashed in the eye and electronic signals from the retina are recorded. In a SARDS patient, the normal electronic responses of the retina are extinguished. Initially, early changes from SARDS are microscopic and therefore ophthalmic examination may reveal normal retinas. After a period of months signs of degeneration of the retina will likely be observed on ophthalmic examination.
Unfortunately, because the primary cause of sudden acquired retinal degeneration syndrome has not been identified, there is currently no proven treatment or prevention and blindness is irreversible.
SARDS is not a painful condition, dogs adjust well to being blind, and are able to resume a normal quality of life. Animals should also be monitored long-term for secondary cataract formation which may require prophylactic medical therapy to control inflammation which could cause discomfort. Safety precautions should be taken, particularly around pools, stairs, roads, etc. There are training techniques and books available to assist you in living with blind dogs.
If you have any question about this information please contact your veterinarian.