Progressive Retinal Atrophy (Swedish vallhund type) is an inherited eye disease affected dogs. Progressive Retinal Atrophy (Swedish vallhund type) occurs due to degeneration of both Rod and cone type Photoreceptor Cells of the Retina, which are important for vision in variable light. Evidence of retinal disease in affected dogs can first be seen on veterinary eye exam as early as 2 months of age. However, first signs of vision loss occur later and have been reported from 1 to 12 years of age. Rod type cells are affected first and dogs will initially have vision deficits in dim light (night blindness). Signs of progressive retinal atrophy on eye exam involve changes in reflectivity and appearance of a structure behind the retina called the Tapetum. The disease follows a variable progression, but most dogs will eventually progress to complete blindness as early as 9 years of age.