Secondary retinoschisis in a dog.

Retinoschisis, an extreme form of cystic degeneration of the retina, was identified as a diffuse, bilateral microscopical change in an 8-month-old, male, English springer spaniel dog with a clinical history of blindness, retinal detachment and glaucoma. The absence of any material in the cystic spaces and the spectrum of intraocular degenerative changes indicated that the retinal change was a secondary retinoschisis, probably due to retinal detachment. Separation of retinal layers without disruption of the blood supply probably plays a part in the aetiology of retinoschisis. The pathogenesis and natural history of intraretinal cystic changes and retinoschisis in animals are poorly understood.