Primary Lens Luxation
Please read this if you are a rat terrier owner. This is important to all rat terrier owners and very critical if you are a breeder.
As of 2017 all of our breeding dogs are PLL Clear so PLL is no longer a concern for any of the puppies that come from us. If you are buying from another breeder always be sure to find out what the puppy’s PLL status is.
In 2010 we became aware that some of our rat terriers carried a genetic disease called Primary Lens Luxation (PLL). A few of our puppy owners contacted us because their rat terrier had developed glaucoma. While it was upsetting to learn that some of our dogs carried PLL, I am very grateful that I was made aware of the problem. If they hadn’t contacted me I wouldn’t have known there was an issue since none of my own dogs have ever developed glaucoma. That is why it is so important to notify your dog’s breeder if an issue comes up. Even if you aren’t sure it’s genetic, it is still a good idea, since issues in a given bloodline can be traced if they are reported.
Until October 15, 2009 there was NO test for PLL. Breeders were having to breed in the dark. But NOW, we have the tool we need to eliminate this disease from our bloodlines. The University of Missouri, College of Veterinary Medicine through the partnership of OFA (Orthopedic Foundation for Animals), now has a DNA test for this mutation.
Below we have compiled information from around the web that is very useful.
Here is a link to OFA’s website where the PLL test can be ordered: OFA PLL test
What is PLL?
“Lens luxation is the dislocation or displacement of the lens within the eye. The lens is the clear structure in the eye, consisting of two rounded or convex surfaces, that focuses light rays to form an image onto the retina. Normally the lens is suspended between the iris (the colored portion of the eye) and the vitreous (the clear gel in the back of the eye), and is held in place by small fibers called zonules or suspensory ligaments.
Should the zonules break, the lens can either become partially dislocated (subluxated) from its normal position or completely dislocated (luxated). When the lens detaches and falls forward into the anterior chamber in front of the pupil, it is called an anterior luxation. When it falls back into the rear portion of the eye, it is called a posterior luxation.”
“Primary lens luxation is an inherited disorder in which the zonules or suspensory fibers degenerate. The condition occurs mainly in the terrier breeds, namely the Parson Russell terrier, Tibetan terrier, smooth fox terrier and rat terrier. Primary luxations are also seen in the border collie, the Australian cattle dog (blue heeler), and sporadically in other breeds. Although the underlying reasons for the lens luxation are not well understood, inflammation or a defect in the zonules may play a role. With primary lens luxations, both eyes are prone to dislocation of the lens.”