Early-onset progressive retinal Atrophy is an inherited eye disease affecting dogs. Early-onset progressive retinal atrophy occurs as a result of degeneration of both Rod and cone type Photoreceptor Cells of the Retina, which are important for vision in dim and bright light, respectively. Affected dogs may present with vision problems from as early as 1.5 years of age, with significant loss of vision by 4.5 years of age. The rod type cells are affected first and affected dogs will initially have vision deficits in dim light (night blindness) and loss of peripheral vision. Over time affected dogs continue to lose night vision and begin to show visual deficits in bright light. Other signs of progressive retinal atrophy involve changes in reflectivity and appearance of a structure behind the retina called the Tapetum that can be observed on a veterinary eye exam. Genetic testing may help clarify if a dog is affected with progressive retinal atrophy early onset or another inherited condition of the eye.