[Retinal dysplasia in dogs--a review]

Retinal dysplasia is a developmental aberration of the neuroretina characterized by formation of retinal tubules, malformation rosettes and folding of the retina. Retinal dysplasia has been reported in Bedlington Terrier, Sealyham Terrier, Beagle, Labrador Retriever, English Cocker Spaniel, American Cocker Spaniel, English Springer Spaniel, Yorkshire Terrier and Rottweiler. A hereditary basis for retinal dysplasia has been proved or suggested for all breeds exhibiting retinal dysplasia except Beagle and Rottweiler. Ophthalmoscopically retinal dysplasia is characterized by vermiform streaks often radiating from the optic disc. The reflectivity of the tapetum is often altered in these areas. Accompanying retinal detachment or cataractous changes in the lens may be seen. Extensive retinal dysplasia and retinal detachment or cataract may result in visual impairment or blindness. Eyes exhibiting retinal dysplasia may be classified according to the number of layers from the retinal structure that are represented in the rosettes. Three-layer rosette. Two-layer rosette. Single-layer rosette. Primitive unilayer rosette. The etiology of retinal dysplasia includes viral disorders, irradiation, X-radiation, intrauterine trauma and heritable factors.