SUDDEN ACQUIRED RETINAL DEGENERATION SYNDROME (SARDS)
Sudden Acquired Retinal Degeneration Syndrome is characterized by a very rapid loss of vision in the dog. It specifically affects the retina which is where all vision starts (the retina is in the back of the eye.).
Currently, SARDS is known to cause a rapid destruction of the photoreceptors (rods and cones) of the retina leading to blindness. The cause for this destruction is currently unknown and is the subject of ongoing research.
Sudden Acquired Retinal Degeneration Syndrome occurs in a wide age range of dogs and can affect any breed. Often owners report unexplained weight gain, increased appetite, and increased water consumption coinciding with the loss of vision. As these are signs of endocrine or hormonal disease, blood work will be recommended to rule out any systemic diseases. Also, an internal medicine consult may be beneficial to ensure there is no underlying and potential treatable condition.
When vision loss is sudden, owners often notice that their pet is confused, may bump into walls and furniture, or may become fearful or aggressive. In addition to the vision loss, owners may notice an increased shine to the eyes due to dilated (large) pupils. These changes can occur overnight.
In any case where vision is lost, a complete ophthalmic exam is necessary. The ophthalmologist will evaluate the front and back of the eye with several instruments. In cases of SARDS, the ocular exam is often completely normal.
Vision is lost at three main locations: the retina, the optic nerve (the extension cord between the eye and the brain), and the brain itself. In order to localize the cause for acute vision loss, an electroretinogram will be recommended. This is a non-invasive diagnostic test that uses flashes of light to quantify retinal function. Patients with SARDS will have extinguished electrical function. If normal retinal function is measured, the patient will need to be evaluated by a neurologist as the lesion will be localized to the optic nerve or brain. An electroretinogram is necessary to provide owners with a definitive diagnosis of SARDS (ruling out brain or optic nerve disease).
As the true cause for SARDS has yet to elucidated, there is unfortunately no effective treatment or prevention for SARDS. The blindness is irreversible. The accompanying symptoms of weight gain, increased appetite, and increased thirst will often subside over the course of several months.
SARDS is not a painful condition. All pets with vision loss maintain an excellent quality of life. Pets are extremely good at adapting to their loss of vision. They have a heightened sense of smell as well as hearing that quickly take the place of vision. They do not experience the depression or other difficulties that a human with vision loss would face. After all, they have you to take care of them! Some pets adapt immediately while others adapt over several months.
Occasionally, secondary cataracts will form months to years after the initial SARDS diagnosis. Your pet’s regular veterinarian or the ophthalmologist can monitor your pet’s eyes for signs of cataracts. Some cataracts do require anti-inflammatory therapy.
Pets affected with SARDS continue to lead happy, healthy, fun filled lives and will continue to be special family members for many years. At South Texas Veterinary Ophthalmology, we want to do everything in our power to keep your pet happy and comfortable. Please let us know if there is any way we can help you or your pet.