Common Causes of Sudden Blindness in Dogs: Sudden Acquired Retinal Degeneration (SARD), Immune-Mediated Retinal Detachment Syndrome and Diabetes Mellitus Induced Mature Cataract are common causes of blindness in dogs. Steve Dugan, DVM, MS, Diplomate of the ACVO Sudden Acquired Retinal Degeneration (SARD)