Clinical trial offers hope to CED sufferers
"Cyrus’ results are exciting because we now know this surgery can help dogs with severe disease, too."
A rescue dog's sight has been restored by an alternative new surgery. Meanwhile, US researchers are hoping to develop a genetic test for corneal endothelial dystrophy (CED).
CED is seen more commonly in German short-haired pointers (GSP) than in many other breeds.
A clinical trial being carried out by scientists at the UC Davis School of Veterinary Medicine in California aims to identify and isolate the gene responsible. It is hoped they will then be able to develop a test for dog breeders, so they can avoid the condition being passed down to their puppies.
Ten-year-old GSP Cyrus was enrolled onto the UC Davis trial by his rescue shelter, the NorCal GSP Rescue in California. Due to CED, Cyrus was losing his sight.
Traditionally the only definitive treatment for the condition is a corneal transplant. This surgery is rarely performed due to the high cost of surgery and after care, the risk of complications and lack of suitable donor tissue.
CED causes the degeneration of endothelial cells, which form the innermost part of the cornea and are responsible for pumping fluid out of the cornea, which is essential for maintaining ocular transparency.
The condition leads to swelling of the cornea and can even result in blindness and severe pain caused by secondary complications. Small fluid-filled blisters called bullae also form on the cornea and rupture, causing discomfort.
While Cyrus was taking part in the clinical trial on the genetic components of this condition, Dr Sara Thomasy, who is leading the research, considered whether Cyrus may benefit from an alternative surgery to treat CED.
The surgery involves thinning part of the cornea by removing an aspect of its front or anterior part. A very thin conjunctival advancement flap is then placed over the removed part. The procedure is known as superficial keratectomy and conjunctival advancement hood flap (SKCAHF).
A prior surgery trial saw promising results in nine dogs - one of which was a GSP.
Dr Thomasy was concerned, however, that Cyrus' corneas were thicker than those of any other dog that had undergone the surgery. Despite this, Cyrus underwent the procedure in March 2014 and his vision had markedly improved after three months. He is now living with a new family.
"We did know that the SKCAHF surgery trial had been very successful in other dogs, including another GSP, but that dog had more moderate disease," said Dr. Thomasy. "Cyrus’ results are exciting because we now know this surgery can help dogs with severe disease, too."
The research team are looking for GSPs, German wire-haired pointers and Boston terriers with CED to take part in their genetic trials. For further information contact Dr Thomasy via email at smthomasy@ucdavis.edu.
RCVS Knowledge has called on vet practices to audit their post-operative neutering outcomes.
