Retinal dysplasia, or RD, is an inherited disorder in which the retina of the eye is malformed. To understand retinal dysplasia it's first necessary to understand the basics of the eye's anatomy. The retina itself is the nerve-containing structure in the back of the eye that takes in light and converts it into electrical signals. These signals are then transmitted to the brain via the optic nerve, and interpreted by the brain as vision. Formation of the eye in utero is a complex, multi-stage process that is closely tied to development of the entire nervous system.
There are three forms of retinal dysplasia. The first and least serious occurs when the two primary layers of the retina do not form together properly, creating folds in the inner retinal layer. In geographic RD there are larger areas where the retina is malformed in addition to the inner retinal layer. In the most severe form of the disease, the two retinal layers do not meet at all, resulting in retinal detachment, or separation, from the rest of the eye.
Unlike many conditions, retinal detachment does not worsen with age. The disease is largely hereditary, and affected animals are born with as severe a condition as they will ever develop. In rare cases, the problem also can be caused by prenatal infections with either the herpes virus or parvovirus.
Affected breeds include: Airedales, Akitas, American Cocker Spaniels, Australian Shepherds, Beagles, Bedlington Terriers, Belgian Malinois, Border Terriers, Bull Mastiffs, Cairn Terriers, Cavalier King Charles Spaniels, Clumber Spaniels, Collies, Dobermans, English Springer Spaniels, Field Spaniels, German Shepherds, Gordon Setters, Labradors, Mastiffs, Norwegian Elkhounds, Old English Sheepdogs, Pembroke Welsh Corgis, Rottweilers, Samoyeds, Sealyham Terriers, Sussex Spaniels and Yorkshire Terriers. There is no means of preventing the problem, which means that affected animals should not be bred. For reasons not yet known, Labrador Retrievers and Samoyeds with retinal dysplasia also often have a form of dwarfism called chondrodysplasia, in which their front legs are shorter and thicker than normal.
Retinal dysplasia can be diagnosed in puppies as young as six to eight weeks of age. However, it's recommended the animal be re-checked at age six months, to confirm the diagnosis. Dogs with retinal folds usually experience only small blind spots in their vision. These are small enough that most dogs usually don't notice them. With geographic dysplasia, however, the dog will experience significant vision problems. Dogs with retinal detachment, meanwhile, will be completely blind.
There is no effective treatment for RD. Most dogs with the disease are able to compensate for any vision loss by using their senses of smell and hearing. Owners can help their affected pets by keeping their environment as consistent as possible, and introducing any necessary changes gradually. Developing regular exercise routes also is helpful.