One of our ophthalmology specialists, Dr. Amanda Corr speaks about cataracts and cataract surgery in dogs. Cataracts are a leading cause of blindness in dogs. Most canine cataracts are inherited with a prevalence of over 11% in some pure breeds and an average age of onset 5-8 years of age. Up to 75% of dogs with diabetes mellitus will develop cataracts leading to significant vision loss within 9 months of the diagnosis.