Pseudoexfoliation Syndrome
From EyeWiki
Pseudoexfoliation syndrome (PXF or PEX) is an age-related systemic syndrome that targets mainly ocular tissues through the gradual deposition of fibrillary white flaky material from the lens, mainly on the lens capsule, ciliary body, zonules, corneal endothelium, iris and pupillary margin. Higher prevalence of open angle glaucoma in about 50% of these patients.
Contents |
Disease Entity
Exfoliation/Pseudoexfoliation syndrome is a systemic disease. It is most commonly noted in older individuals, typically over 50 years of age.
Disease
Exfoliation (pseudoexfoliation) Syndrome is characterized by the fibrillar deposits in the anterior segment of the eye. The deposits have been found on and in the subconjunctival tissue, pupillary margin, ciliary epithelium, lens epithelium, lens capsule, iris pigment epithelium, trabecular meshwork,cornea,zonules, orbital soft tissues, iris stroma and iris blood vessels. These deposits have also been found elsewhere in the body,including in the skin, heart, lungs, liver, kidneys, and elsewhere.[1]
The disease may be bilateral by asymmetric.
It has been associated with myocardial infarction, cerebrovascular events and systemic hypertension.
Etiology
Etiology is unknown. It may a generalized disorder involving abnormal production or turnover of extracellular matrix in the basement membrane.
Risk Factors
- Advance age over 70
- Possible genetic prevalence
- Its prevalence in different human populations especially, it is prevalent in Scandinavia.
General Pathology
The deposits are composed of elastic fibers (fibrillin and α-elastin)and noncollagenous basement membrane materials (laminin)which form fibrils. They are coated with the glycosaminoglycan hyaluroni acid.
Pathophysiology
Unclear, but there is a gentic link to the gene LOXL1. In March 2008 of the American Glaucoma Society in Washington, D.C. Dr. Allingham. described a LOXL1 is a member of a family of enzymes that are active in the cross-linking of collagen and elastin in the extracellular matrix, he explained. “Because pseudoexfoliation syndrome is associated with abnormalities of the extracellular matrix and the basement membrane, this gene could reasonably play a role in the pathophysiology of the condition.”
Primary prevention
- Routine annual eye exam by an ophthalmologist for the patients over ago 50.
- Biomicroscopic examination(Slit Lamp) used by an eye doctor to examine the anterior lens capsule, pupillary dilation, intraocular pressure and optic nerve.
- Treatment of elevated eye pressure with eye drops, laser or surgery.
- Special precaution and awarness is essential prior and during cataract surgery.
- Anterior chamber depth less than 2.5mm centrally could be an indication of zonular instability
- Poor pupillary dilation
- Zonular dialysis
- Phacodonesis
All of the above may poses a significantly higher risk for intraoperative complications.
- Diagnosis
Diagnosis is done by an eye exam using slit lamp and intraocular pressure exam. On regular routine exam an eye doctor could see a white fluffy material deposit on the anterior lens casule, and pupillary margin. Gonioscopy may show increase pigment deposit on the Trabecular Meshwork.
History
In 1971, a Finnish ophthalmologist John Linberg is the first doctor who described Pseudoexfoliation syndrome. He reported the classic findings of white/grey flakes on the anterior lens capsule, glaucoma in approximately 50% of eyes, and an increasing prevalence of the condition with advancement of the age. A few decades later, an American ocular pathologist named Georgiana Dvorak-Theobald suggested the term pseudoexfoliation to distinguish it from the true exfoliation syndrome. True exfoliation is caused by heat from glassblowing or infrared radiation exposure in the anterior lens capsule. It is characterized by "lamellar delamination of the lens capsule".
Physical examination
Poor pupillary dilation, transillumination defect on the pupilary borders, white fluffy deposits on the anterior lens capsule
Signs
Increased intraocular pressure
Poor dilation with peripupillary transillumination defect
fibrin white flaky deposits on the anterior lens capsule
Symptoms
No real symptom is associated with it, most of the finding are based on an eye exam. The intraocular eye pressure elevation may not have symptom.
Clinical diagnosis
By an eye exam for patients over 50.
Diagnostic procedures
Slit lamp exam
Intraocular pressure check
Pupil check and transillumination exam
Dilated eye exam to check optic nerve
Gonioscopy to check for trabecular meshwork hyperpigmentation and open angle
Laboratory test
Genetic test for a single mutation in the LOXL1
Check for Homocysteine level in tear film and plasma. Scientists believe that elevated levels of plasma homocysteine are a risk factor for cardiovascular disease, and two studies have found higher levels of plasma and tear fluids homocysteine level in Psuedoexfoliation patients.
Differential diagnosis
LENS CAPSULE: True exfoliation
TRABECULAR MESHWORK HYPERPIGMENTATION/GLAUCOMA: Pigment dispersion,
IRIS TRANSILLUMINATION DEFECTS: Pigment dispersion
Management
Routine regular eye exam
Glaucoma treatment if the patient developes it
Special surgical precaution for cataract surgery pre-intra and post operation
General treatment
Add text here
Medical therapy
Eye drops if the patient has glaucoma
Use of Antioxidants
Lower Homocysteine if the level is high in plasma or tear film
Medical follow up
Routine annual eye screening exam with dilation, if the patient has glaucoma then he/she needs 3-4 time per year eye exam.
Surgery
Add text here
Surgical follow up
Add text here
Complications
Glaucoma or optic nerve cupping
Cataract surgery complications:
- drop nucleus or lens fragment
- Zonular dialysis
- Phacodonesis
- Lens subluxation, either the natural lens or intraocular lens
other systemic problems
Prognosis
Add text here
Additional Resources
Add text here
References
Add text here
