Isaac Point Kennels

Canine Lens Luxation Basics

Elizabeth A. Giuliano, DVM, MS

Diplomate, American College of Veterinary Ophthalmologists

Assistant Professor, University of Missouri, College of Veterinary Medicine

The lens of the eye normally lies immediately behind the iris and the pupil, and is suspended in place by a series of fibers, called zonular ligaments. It functions to focus light rays on the retina, in the back of the eye. When partial or complete breakdown of the zonular ligaments occurs, the lens may become partially dislocated (Lens Subluxation) or fully dislocated (Lens Luxation) from the lens’ normal position. Movement of the lens forward through the pupil into the Anterior Chamber of the eye is termed Anterior Lens Luxation. Movement of the lens backwards into the Vitreous Chamber of the eye is termed Posterior Lens Luxation.

What Causes Lens Luxation?

Lens Luxation can occur for a several different reasons.

Primary Lens Luxation is a heritable disease in many breeds, including many terrier breeds (Jack Russell, Bedlington, Fox, Manchester, Miniature Bull, Scottish, Sealyham, Welsh, West Highland White), Tibetan Terrier, Border Collie, Brittany Spaniel, German Shepherd and Welsh Corgi. In these breeds, spontaneous luxation of the lens occurs in early adulthood (most commonly 3-6 years of age) and often affects both eyes, although not necessarily at the same time. Primary Lens Luxation is caused by an inherent weakness in the zonular ligaments which suspends the lens.

Lens Luxation can also occur secondary to other primary problems of the eye, including inflammation, cataracts, glaucoma, cancer, and trauma.

What is the Significance of Lens Luxation?

Lens Luxation can lead to inflammation (Uveitis) and Glaucoma (increased intraocular pressure). This can result in painful, teary, red eyes that may look hazy or cloudy. Both Uveitis and Glaucoma are painful and potentially blinding diseases if not identified and treated early.

How is Lens Luxation treated?

In all cases, a thorough eye exam by your veterinarian or a veterinary ophthalmologist is required, with careful evaluation for uveitis and glaucoma. If detected early, surgical removal of the lens can be beneficial. Medical treatment of inflammation and glaucoma in the form of topical and oral medications can relieve much of the discomfort associated with this disease.

OFA's Policy on DNA Clear By Parentage

As a greater number of DNA based disease tests become available, a policy regarding the clearing of offspring out of DNA tested parents has become necessary.

For direct mutant gene tests only, the OFA will issue clearances to untested offspring, if the sire and dam have both been DNA tested "clear," if the sire and dam’s DNA disease test results have been OFA registered, and if all three (sire/dam/offspring) have been DNA identity profiled and parentage verified. The DNA profile paperwork must be submitted along with a completed OFA DNA-based disease test application. The resulting OFA certification will have a suffix of "CBP" (clear by parentage), indicating that the dog itself was not tested and that the clearance was based on the sire and dam’s test results, and known science at the time. Because of the possibility of new mutations or as of yet undiscovered gene mutations, only first generation offspring will be cleared.

For linkage or marker based tests where a margin of error including both false positives and negatives exists, the OFA will not issue any clearances to untested dogs.

DNA based disease screening is an evolving area. This policy is subject to change by action of the OFA Board of Directors as technology and science advance.