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. [...]
The retina is a structure in the back of the eye. It is responsible for receiving light through the lens and converting it into electric signals that can be transmitted to the brain and perceived as sensory data. It is quite a complex instrument, and as such, malformations can occur during its development. These are rare problems, but certain factors such as the breed of your dog and certain matters of heredity can affect the likelihood of contracting them.
Retinal dysplasia is a disorder that occurs when the two layers of the retina do not form together in the correct manner during the formation of the fetus. In its mildest form, this causes light accordion-style folding to occur on the inner layer of the retina, which are called "retinal folds". This disorder is not progressive, which means that whatever degree of severity a puppy possesses at birth is as severe as the disease will ever get. [...]
The Cardigan Welsh Corgi is a relatively healthy breed, though as usual the breed is not without its typical health issues. These dogs suffer from a series of eye problems that, though not frequently recorded in the breed, do show up from time to time and can cause serious, lasting damage, depending on the severity of the condition. The Cardigan is prone to Progressive Retinal Atrophy (PRA), like many dogs, as well as lens luxation and retinal dysplasia. If you suspect any of these conditions, you should immediately take your dog to the veterinarian, who may suggest you see a veterinarian ophthalmologist. [...]
English Springer Spaniels are generally healthy dogs, but within the breed, there are some common health problems. The breed is prone to hip dysplasia, progressive retinal apathy, retinal dysplasia and phosphofructokinase deficiency. Owners should contact a veterinarian if symptoms present themselves. [...]