The Paw Print Genetics Blog

Rickie Roo is an agility dog, a service dog and a roving reporter for the United States Dog Agility Association. She is well known in the sport of agility and in the rat terrier community. On October 12^th, 2013, Roo unfortunately had to have emergency surgery because of a luxated lens in her left eye. Primary Lens Luxation, or PLL, is a condition that can happen in many breeds including American Eskimo dog, American hairless terrier, Australian cattle dog, border collie, bull terrier, Chinese crested, Jack Russell terrier, jagdterrier, Lakeland terrier, Lancashire heeler, miniature bull terrier, Norwich terrier, Parson Russell terrier, Patterdale terrier, rat terrier, Russell terrier, Sealyham terrier, Teddy Roosevelt terrier, Tenterfield terrier, Tibetan terrier, toy fox terrier, Volpino Italiano, Welsh terrier, wire fox terrier, Yorkshire terrier.

Lens luxation can happen suddenly and when it occurs, needs to be surgically corrected as soon as possible to try to minimize any loss of sight. Luckily, Rickie Roo's luxated lens was caught very early by her owner, Deborah Davidson Harpur. Thanks to early intervention, Rickie Roo has an 85 percent chance of vision in that eye after surgery. Her veterinarian, Dr. Christin Fahrer, DVM, MS, DACVO believes that Roo can probably still do agility but her depth perception will be significantly impaired and will not be as it was before the injury occurred. 

PLL is characterized by the dislocation of the lens in the eye thought to be due to the breakage of the ligaments or zonules that hold the lens in its normal place. Affected dogs may present with sudden signs of irritation in the eye with excessive twitching, blinking and tearing of the eye. Cataracts and inflammation of the eye are also associated. Dislocation of the lens can occur in both the forward and backward position within the eye, but dislocation in the forward position is more common and serious. If not treated immediately, lens dislocation can lead to glaucoma (increased pressure in the eye) and vision loss.

Rickie Roo was bred and born before the mutation in the ADAMTS17 gene was identified and a test was developed.  After she was born, her breeder tested her breeding stock and contacted anyone who might either have purchased an affected dog or one that carries the mutated gene. Genetic testing of the ADAMTS17 gene will reliably determine whether a dog is a genetic carrier of PLL. PLL is inherited in an autosomal recessive manner in dogs. In most cases, carriers of the mutation do not show symptoms of the disease. However, in rare instances, some carrier dogs have been reported to have PLL. Therefore, all dogs that tested as affected (two copies of the mutation) or at-risk carriers (one copy of the mutation and one copy of the normal gene) should be periodically checked by a veterinary ophthalmologist for signs of luxation. In addition, you should watch for sudden changes in behavior and any squinting, excessive blinking, or pawing at the eye, which may indicate a sudden lens problem that will need immediate attention. Surgery can be costly, estimated around $4,300 to remove the damaged lens. 

Roo was genetically tested for PLL and found to be at-risk a few years ago, so her owner knew that the condition was always a possibility. However, being at-risk for PLL does not guarantee your dog will develop a lens luxation. Roo had an unrelated eye injury before the DART 4 star event a few years back and at that time Roo and her owner met with Dr. Fahrer of Eye Care for Animals who they have been seeing ever since. Dr. Fahrer comes highly recommended by Roo’s owner and reportedly is very direct, practical and understanding about your dog’s eye concerns.

Roo is now recuperating at home and tolerating her eye drops well.  She still loves her cookies and is looking forward to getting back to agility, the sport she loves. Right now her biggest concern is the unflattering cone that she adorns, but it is worth it to make sure her eye heals properly.

To know if your dog may be at-risk for sudden lens luxation, you can have your dog’s DNA examined for the mutation in the ADAMTS17 gene.  Paw Print Genetics offers PLL testing and would welcome the opportunity to discuss your dog’s genetic health with you.  We know that having healthy, happy dogs is your primary objective and we are here to help.

Update:  Approximately two weeks after Roo's left eye lens required surgical removal due to luxation, her right lens also dislocated and required immediate surgery. We wish Roo a speedy recovery!

Photographs courtesy of Deborah Davidson Harpur and Rickie Roo.  Upper left shows Rickie Roo before the lens luxation. Upper right shows Roo’s left eye after the lens dislocated.  Bottom left and right show Roo’s amazing ability in the agility ring.