Research of Poodle Eye Diseases Needs Support from Breeders & Owners
Eye diseases in Poodles have long been a health concern. When Poodles joined the Canine Health Information Center (CHIC) program in 2004, eye examinations were one of the initial requirements across all three varieties for CHIC certification. Despite efforts to encourage eye tests and advise breeders to selectively breed against eye diseases, one expert notes an ongoing steady increase in Poodle eye diseases.
Gustavo Aguirre, VMD, PhD, professor of medical genetics and ophthalmology at the University of Pennsylvania School of Veterinary Medicine, says, “Vision problems still affect far too many Poodles. Compounding efforts to identify gene mutations, we have a shortage of DNA samples from all varieties of Poodles. It takes a commitment from breeders and owners working with researchers to help advance discovery of causative gene mutations. Then, it’s up to breeders to selectively breed dogs that will not produce offspring with eye diseases.”
In efforts to better understand the genetics and treatment options for eye diseases, the Poodle Club of America Foundation is helping to fund eye disease research. Currently, the Foundation is supporting genetic research of polymicrogyria and day blindness/retinal degeneration in Standard Poodles, as well as studies of optic nerve hypoplasia/micropapilla and cataracts in Miniature and Toy Poodles.
Neurological Disease PMG & Vision Problems
There was nothing unusual about the newborn black Standard Poodle at first. Like her littermates, she felt and sniffed her way around the whelping box. When their eyes began to open, she continued to find her way around by smelling and feeling.
Curtisy Briggs of Malvern, Pennsylvania, adopted the puppy in December 2002 at 10 weeks of age knowing she was blind. “I named the puppy ‘Celie’ after the protagonist in ‘The Color Purple,’" she says.
Unbeknownst to Briggs at the time, Celie suffered from the neurological condition polymicrogyria (PMG), which often but not always affects vision. The puppy’s eyes had normal vision. The optic nerves that carry visual signs to relay centers in the brain, which control pupil reflexes, eye movement and some visual processing, were normal, as were the relay centers. The abnormality was at the visual cortex. All that Briggs knew was that Celie was basically blind and had somewhat odd behavior.
Located near the rear of the outside surface of the brain, the visual cortex processes visual signals into recognizable objects. The brain’s surface, or cortex, is normally covered in large folds called gyri. However, in dogs with PMG, the cortex has many excessive small folds, or gyri, that disrupt normal connections within the cortex. Functioning of the temporal cortex, located in front of the visual cortex, may be severely affected as well. The temporal cortex is involved in emotional responses, which is why some dogs with PMG have personality issues and seizures.
Dr. Aguirre has examined quite a few Standard Poodles with PMG and described a range of phenotypes. “Some dogs are able to see more than others,” he says. “Most, but not all, have a form of hydrocephalus, or fluid buildup in the cavities deep within the brain. We see one to two cases a year. There are undoubtedly more cases, though most affected dogs are likely euthanized as puppies. It also is likely that dogs that are mildly affected are just not diagnosed unless a magnetic resonance imaging (MRI) study is done.”
The good news is that with help from researchers and diligent breeders who regularly health test their breeding stock, some of the hereditary eye diseases such as PMG may one day no longer be a problem.