PLL
Dislocation of the Crystalline or Primary Lens Luxation (PLL)
First, a little anatomy of the eye
The transparent portion to the front of the eyeball is called the cornea (cornea). Around the cornea is the conjunctiva (conjunctiva) and below the sclera (sclera). Behind the cornea is the anterior chamber ocular (aqueous humor) filled with a liquid, which serves to hold the eye on. After the iris is the color varies.
In the middle of the iris is an opening, it is the pupil. If the light is intense it is contracted and small. When it is dark it expands. The lens lies behind the iris and is completely surrounded by a membrane (lens capsule). When the lens has a normal brightness is invisible to the naked eye and the pupil looks like a black circle in the middle of the eye.
The lens is held in place by small fibers called "zonules" (suspensory ligament) (These are the zonules of the lens edge, this edge is also called equator to the ciliary body (ciliary muscles), this is a small bulge behind the iris. Behind the lens is a gelatinous mass, also called "glass." In front of this glass is a kind of hollow in which is placed the lens. hollow It is called "patellar fossa." the eye constantly produces moisture which is removed regularly by the filtration angle, which lies between the base of the iris and cornea. At the back of the eye are the retina and the pupil.
Normally the lens lies behind the iris in the development of the vitreous. It is held in place by fibers which lie between the edge of the lens and the ciliary body.
.
The Primary lens luxation or dislocation Lens (PLL)
It occurs when the fibrous ligament of the eye that secures the lens deteriorates, causing displacement of the lens from its normal site (behind the pupil) to:
- The posterior chamber of the eye (fig. a) the eyeball normally present.
- The anterior chamber of the eye (fig. b, c, d): the lens moves and irritates the cornea causing watery eyes and a runny blue in the eye.
Anterior dislocation is the most risky because there is a high probability of glaucoma (increased pressure in the eyeball caused by an interruption of the fluid exchange - the aqueous humor which is in front of the lens - between the globe and venous circulation. It leads to partial or complete blindness and is the primary form (congenital).
The primary difference between dislocation and dislocation secondary crystalline
Primary lens luxation involves well-defined races at an age well defined. It attacks both eyes when the dog does not suffer from other eye diseases that could be causing the problem.
The secondary lens luxation can occur at any age from any race. Another eye disease is responsible, perhaps glaucoma (eye pressure initially increased and the eyeball has expanded causing a shift of the lens). Trauma, serious eye infection, cataracts and eye tumors can cause lens luxation.
An autosomal recessive disease
Primary dislocation (congenital) of the lens is autosomal recessive, each parent must be at least carry the disease. If a dog is suffering, all his descendants are carriers of the disease.
Affected dogs should not be used for breeding, more insidious this disorder appears between 3-8 years, although in the middle of the breeding program.
Dogs healthy carriers may or may not be excluded from reproduction, but avoid coupling two healthy carriers together: the puppies would be 25% chance of being healthy, but 50% would be healthy carriers and 25% met.
This disease is very painful.
Gene distribution
Each dog has a pair of genes that carry defects.
During fertilization, each dog brings a gene, there are four possibilities :
Dominance
Géne "Healthy"
is dominant over the gene "sick" 
This will define three categories of dogs :
- Healthy dogs
- Dog carriers, dog carrier of a gene "sick" but never develop the disease.
- Affected dogs develop the disease
Observe your dog before the onset of dislocation, you may notice a change in behavior: bumping against objects, miss a stair, not tracking the ball or biscuit etc. ...
Treatment is variable:
- Excision of the lens, allowing a partial view (expensive and not always effective).
- Enucleation of the eye, for severe cases.
The PLL is a recessive disease: it means that both parents carry the disease but does not declare the PLL can cause puppies that will later be achieved. Here is a chart to help you better understand the mode of transmission :
Example: a standard (or breeding female) whose father (or mother) will be achieved luxury of lens dislocation (50% chance) or be healthy carriers (50% remaining), c 'is to say that dog is predisposed to transmit the disease to its offspring..
Un test ADN est maintenant disponible !!
DNA testing is now available!
A mutation that causes the development of primary lens luxation (PLL) in many breeds of dogs has been identified by a team of researchers led by Dr. Gary Johnson & Elizabeth Giuliano at the University of Missouri "College of Veterinary Medicine" . A DNA test for this mutation became available in mid-September 2009, through a partnership with the OFA (Orthopedic Foundation for Animals).
Shortly after the announcement by the University of Missouri researchers "the Animal Health Trust in England," also announced that they had found a mutation in the PLL. Dr Catherine Mellersh and Dr David Sargen the AHT contacted Dr. Johnson, and the two research teams have agreed to share data and co-publish this discovery. PLL tests will also be available through the AHT in England, at a price comparable to the tax OFA.
To order the test in France : https://antagene.com/
Here the test of parents or ascendants will be sent on the day you pick up your baby..