Sudden Acquired Retinal Degeneration Syndrome (SARDS) in Animals
Sudden acquired retinal degeneration syndrome occurs in dogs, with Dachshunds, Miniature Schnauzers, Pugs, and Brittany Spaniels reported to be more commonly affected. Clinical findings include acute loss of vision (often occurring throughout several days), widely dilated and poorly responsive to nonresponsive pupils, and a relatively normal-appearing fundus. Dogs affected most often are middle-aged to older, with spayed females overrepresented, often presenting with clinical signs that include weight gain, lethargy, polyuria, polydipsia, and polyphagia.
Color pupillometry can help with the diagnosis, because the red pupillary light reflex is absent whereas a blue pupillary light reflex remains. Electroretinography by an ophthalmologist is required for a definitive diagnosis; a flat-line electroretinogram is observed with sudden acquired retinal degeneration sydrome. By contrast, a normal electroretinogram is indicative of optic pathway disease, and further testing with a neurologist is warranted. Within a few months, signs of retinal degeneration can be observed on fundic examination, including tapetal hyperreflectivity and retinal vascular attenuation. To date, no effective treatment has been reported.