Progressive retinal atrophy (PRA) is a group of hereditary photoreceptor disorders of the retina that are caused by different mutations in different dog breeds.

A distinction is made between late-developing degenerative changes and dysplastic disorders that already manifest clinically in puppyhood. Apart from the age at which the disease appears, the clinical and ophthalmologic symptoms are similar. Affected dogs show bilateral mydriasis, the tapetum lucidum is more reflective and the retinal vascular network appears atrophic.

A genetic variant of the GUCY2D gene can be associated with an early form of PRA in Spitz. The affected dogs already show impaired vision at the age of 3 months, both in daylight and at night. They have a pale optic disc, the number of retinal blood vessels is slightly reduced and some affected puppies also suffer from nystagmus (eye tremors). While the function of the photoreceptors is already severely impaired or even completely disrupted at the age of a few months, the retinal structure initially appears to be well preserved. Only in older affected dogs can a slight thinning of the retina be observed.