Progressive retinal Atrophy (PRA) (giant schnauzer type) is an inherited eye disease affecting dogs. PRA (giant schnauzer type) causes degeneration of both Rod and cone type Photoreceptor Cells of the Retina. These are important for vision in dim and bright light, respectively. Affected dogs present with changes in reflectivity and appearance of a structure behind the retina called the Tapetum. A veterinarian may observe this during an eye exam. Additionally, thinning of the retinal blood vessels may also be observed. Affected dogs will have gradual vision loss, eventually progressing to complete blindness in most cases.