Canine Lens Luxation Basics
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.