Progressive retinal Atrophy, cone-Rod dystrophy (PRA-crd) is an early-onset, inherited eye disease affecting dogs. PRA-crd 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. Abnormalities can be seen on an Electroretinogram by 5 weeks of age. However, diagnosis during a standard veterinary ophthalmic exam is not typically possible until 10 months to 3 years of age. In affected dogs, Cone Cells degenerate first resulting in blindness in bright light (“day blindness”). Over time, affected dogs also develop rod cell dysfunction in the retina resulting in complete blindness. Complete retinal atrophy and blindness is usually seen by 6 years of age, although disease progression is variable in affected dogs.