Ophthalmology – Pseudoexfoliation Syndrome

Basics

Description

Pseudoexfoliation syndrome (PXS), also called exfoliation syndrome (XFS), is an age-related systemic extracellular matrix disorder characterized by production and deposition of abnormal fibrillar pseudoexfoliative material within the anterior segment.

Deposits occur on structures including:

• Anterior lens capsule
• Pupillary margin
• Iris
• Ciliary body
• Zonules
• Corneal endothelium
• Trabecular meshwork

Its two major ophthalmic consequences are:

• Secondary open-angle glaucoma
• Zonular weakness complicating cataract surgery

When glaucomatous optic neuropathy develops, the condition is termed:

Pseudoexfoliative glaucoma / exfoliation glaucoma (PXG/XFG)

Key Clinical Concept

The classic examination finding is:

Gray-white pseudoexfoliative material on the anterior lens capsule, especially after dilation

combined with:

• Poor pupillary dilation
• Peripupillary iris transillumination
• Dense angle pigmentation
• Sampaolesi line
• Zonular weakness

PXG is often:

More aggressive than primary open-angle glaucoma (POAG)

with:

• Higher IOP
• Greater IOP fluctuation
• Faster progression
• More frequent need for surgery

Pseudoexfoliation vs True Exfoliation

These are different disorders.

Pseudoexfoliation

• Abnormal fibrillar extracellular material
• Associated with glaucoma and zonulopathy
• Usually older adults

True Exfoliation

• Delamination of the anterior lens capsule
• Historically associated with intense infrared exposure, such as glassblowing
• Does not represent the same fibrillopathy

Epidemiology

PXS is strongly age-related and is uncommon before:

50–60 years

Prevalence varies substantially among:

• Geographic regions
• Ethnic groups
• Populations

High prevalence has historically been reported in:

• Scandinavian countries
• Northern Europe

but PXS occurs worldwide.

Laterality

PXS is frequently:

• Bilateral
• Markedly asymmetric

A patient may appear clinically unilateral for years.

The fellow eye may already have subclinical disease even when classic deposits are absent.

Risk Factors

Important associations include:

• Increasing age
• Family history
• Certain ethnic/geographic populations
• Genetic susceptibility

Female predominance is reported in some populations, but this is not universal.

Genetics

The strongest genetic association is with:

LOXL1

not “LOL1.”

LOXL1 encodes lysyl oxidase-like 1, which participates in:

• Elastin formation
• Extracellular matrix maintenance

LOXL1 Important Principle

LOXL1 risk variants are:

• Very common in the general population
• Present in many people who never develop PXS

Therefore:

LOXL1 testing has no routine clinical diagnostic or predictive role.

PXS is considered:

Multifactorial

with both genetic and environmental contributions.

Other Genetic Associations

Additional genes and pathways involving:

• Extracellular matrix regulation
• Oxidative stress
• Elastic fiber biology

have been implicated.

However, routine genetic testing is not currently indicated.

Pathophysiology

Pseudoexfoliative material is produced by several anterior segment tissues and deposited throughout the eye.

The abnormal material contains:

• Elastic microfibrillar components
• Glycoproteins
• Proteoglycans
• Basement membrane-related proteins

Altered extracellular matrix regulation and oxidative stress contribute to disease.

Glaucoma Mechanism

The principal glaucoma mechanism is:

Open-angle outflow obstruction

due to accumulation of:

• Pseudoexfoliative material
• Iris pigment
• Cellular debris

within the trabecular meshwork and juxtacanalicular tissue.

This produces:

• Increased outflow resistance
• Elevated IOP
• Large diurnal IOP fluctuations

Why Pigment Is Increased

Pigment liberation results from:

• Iris rubbing against the lens and zonules
• Degenerative iris changes
• Pupillary movement

This produces:

• Trabecular pigmentation
• Sampaolesi line
• Pupillary margin changes

Angle Closure

Although PXG is usually an:

Open-angle glaucoma

angle closure can also occur because of:

• Zonular weakness
• Anterior lens displacement
• Lens subluxation
• Pupillary block
• Progressive angle narrowing with age

Therefore:

Gonioscopy is essential.

Zonular Pathology

Pseudoexfoliative material accumulates on and around the zonules.

This leads to:

• Zonular fragility
• Phacodonesis
• Iridodonesis
• Lens subluxation
• Intraoperative zonular dialysis
• Late IOL–capsular bag dislocation

This is one of the most important practical consequences of PXS.

Corneal Changes

PXS may affect the corneal endothelium and is associated with:

• Reduced endothelial cell density
• Abnormal endothelial morphology
• Pigment deposition
• Increased risk of postoperative corneal edema

Severe endothelial compromise may occasionally cause:

• Corneal decompensation

Systemic Nature

Pseudoexfoliative material has been identified histologically in extraocular tissues.

Associations with:

• Cardiovascular disease
• Cerebrovascular disease
• Hearing impairment
• Vascular dysfunction

have been reported.

However:

The clinical significance of these systemic associations remains inconsistent, and routine systemic screening solely because of PXS is not established.

History

Most patients are:

Asymptomatic

until they develop:

• Glaucoma
• Cataract
• Lens instability

Ask about:

• Family history of glaucoma
• Previous high IOP
• Cataract surgery
• Trauma
• Fluctuating vision
• Progressive visual field loss

Slit-Lamp Examination

Typical findings include:

• Pseudoexfoliative material on anterior lens capsule
• Flakes at pupillary margin
• Poor pupillary dilation
• Loss of pupillary ruff
• Peripupillary transillumination
• Pigment on corneal endothelium
• Phacodonesis
• Iridodonesis

Classic Lens-Capsule Pattern

After dilation, the anterior lens capsule may show three zones:

1. Central gray-white disc
2. Intermediate clear zone
3. Peripheral granular ring of pseudoexfoliative material

The clear zone forms because the moving iris rubs material from the capsule.

This is a classic exam finding.

Pupillary Margin

Pseudoexfoliative material may accumulate as:

• White dandruff-like flakes

along the:

Pupillary ruff

Associated findings include:

• Loss of pupillary ruff
• Poor dilation
• Iris sphincter atrophy

Iris Transillumination

Typical defects are:

Peripupillary / pupillary-border transillumination defects

producing a moth-eaten appearance.

This helps distinguish PXS from pigment dispersion syndrome, where transillumination defects are usually:

Radial and midperipheral.

Poor Mydriasis

Poor dilation is common because of:

• Iris stromal degeneration
• Sphincter dysfunction
• Posterior synechiae in selected cases
• Mechanical changes associated with PXS

This is an important cataract-surgery risk factor.

Corneal Endothelium

Possible findings include:

• Scattered pseudoexfoliative deposits
• Pigment
• Endothelial changes

A Krukenberg spindle can occasionally occur but is much more characteristic of pigment dispersion.

Gonioscopy

Typical findings include:

• Open angle
• Increased trabecular pigmentation
• Often patchy or asymmetric pigmentation
• Sampaolesi line

Sampaolesi Line

A Sampaolesi line is pigment deposited anterior to:

Schwalbe line

It is commonly seen in:

• PXS
• Pigment dispersion

and is not pathognomonic.

Intraocular Pressure

IOP may be:

• Normal
• Intermittently elevated
• Persistently elevated

PXG often produces:

• Higher peak IOP
• Greater diurnal fluctuation
• More asymmetry between eyes

than POAG.

Pseudoexfoliation Syndrome vs Pseudoexfoliation Glaucoma

PXS

• Pseudoexfoliative material present
• No definite glaucomatous optic neuropathy required

PXG

• PXS findings
• Elevated IOP often present
• Glaucomatous optic nerve/RNFL damage
• Corresponding visual field loss

Optic Nerve Evaluation

Assess for:

• Neuroretinal rim thinning
• Focal notching
• RNFL defects
• Disc hemorrhage
• Increased cupping
• Inter-eye asymmetry

OCT

Obtain:

• Peripapillary RNFL
• Macular GCIPL/GCC
• Optic nerve head analysis

Progression analysis is valuable because PXG may progress rapidly.

Visual Fields

Automated perimetry may demonstrate:

• Nasal step
• Paracentral scotoma
• Arcuate defects
• Advanced field constriction

Because progression can be fast, field testing may need to be more frequent than in stable mild POAG.

Pachymetry

Measure central corneal thickness as part of glaucoma assessment.

CCT should influence:

• Risk interpretation
• Understanding of measured IOP

but should not be used with a simplistic numerical IOP “correction formula.”

Gonioscopy Before Dilation

Gonioscopy is useful before cataract surgery and glaucoma management to identify:

• Open vs narrow angle
• Degree of pigmentation
• PAS
• Lens-related angle crowding

Differential Diagnosis

Important differentials include:

• Pigment dispersion syndrome
• Primary open-angle glaucoma
• Chronic angle-closure glaucoma
• Uveitic glaucoma
• True exfoliation of lens capsule
• Pigment from previous trauma or surgery

PXS vs Pigment Dispersion Syndrome

PXS

Typically:

• Older patient
• Poor dilation
• Peripupillary transillumination
• Pseudoexfoliative material
• Zonular weakness
• Patchier angle pigment

Pigment Dispersion

Typically:

• Younger myope
• Deep anterior chamber
• Radial midperipheral transillumination
• Krukenberg spindle
• Dense homogeneous trabecular pigmentation
• No characteristic progressive zonulopathy

PXS vs POAG

POAG lacks:

• Pseudoexfoliative deposits
• Peripupillary transillumination pattern
• Zonular weakness
• Characteristic poor dilation

PXG often has:

Higher and more fluctuating IOP than typical POAG.

Treatment – PXS Without Glaucoma

If there is:

• Normal IOP
• Normal optic nerve
• Normal OCT
• Normal visual field

treatment is usually:

Observation

with periodic glaucoma surveillance.

Ocular Hypertension in PXS

PXS with elevated IOP carries a greater glaucoma risk than uncomplicated ocular hypertension.

Consider:

• Closer monitoring
• Lower threshold for treatment

depending on:

• IOP level
• Age
• Optic nerve
• CCT
• Family history
• Follow-up reliability

Treatment of PXG

Treatment aims to achieve a target IOP sufficient to prevent progression.

Because PXG may progress faster than POAG:

A relatively low target IOP may be necessary.

Medical Therapy

Common medications include:

• Prostaglandin analogs
• Beta-blockers
• Carbonic anhydrase inhibitors
• Alpha-2 agonists
• Rho-kinase inhibitors where available
• Fixed combinations

Prostaglandin Analogs

Prostaglandin analogs are commonly effective first-line therapy because of:

• Strong IOP reduction
• Once-daily dosing
• Good adherence profile

Selective Laser Trabeculoplasty

SLT is highly effective in many eyes with PXG.

Advantages include:

• Strong IOP response
• Avoidance of daily medications
• Suitability as primary or adjunctive treatment

SLT Considerations

The trabecular meshwork in PXS may be heavily pigmented.

Therefore:

• Start with appropriate/lower energy
• Titrate carefully
• Monitor for post-laser IOP spike

The initial response may be excellent but can diminish with time.

Important Modern Point

SLT is no longer merely a “second-line” treatment.

It may reasonably be used as:

First-line IOP-lowering therapy

in appropriate open-angle PXG.

Cataract Surgery

Cataract surgery in PXS requires special planning because of:

• Poor dilation
• Weak zonules
• Dense nucleus
• Increased risk of vitreous loss
• Increased postoperative inflammation

Preoperative Cataract Assessment

Look specifically for:

• Phacodonesis
• Iridodonesis
• Lens decentration
• Asymmetric anterior chamber depth
• Previous zonular dialysis
• Poor mydriasis
• Endothelial compromise

Intraoperative Risks

Possible complications include:

• Zonular dialysis
• Capsular rupture
• Vitreous loss
• Dropped lens material
• Capsular instability
• Iris trauma
• Corneal endothelial injury

Small-Pupil Management

Options include:

• Intracameral mydriatics
• Viscomydriasis
• Iris hooks
• Pupil expansion ring

Mechanical expansion should be used when necessary rather than forcing surgery through an inadequate pupil.

Zonular Support

Depending on zonular status, options include:

• Capsular tension ring (CTR)
• Capsular hooks
• Capsular tension segment
• Scleral fixation strategies

Capsular Tension Ring

A CTR can redistribute zonular forces in selected eyes with:

• Mild–moderate generalized zonular weakness

However:

A CTR does not guarantee long-term bag stability.

Late IOL–capsular bag complex dislocation can still occur.

Severe Zonular Weakness

With major zonular loss, more advanced support may be required, such as:

• Capsular tension segment
• Scleral-fixated capsular device
• Alternative IOL fixation

An experienced anterior segment surgeon is often appropriate.

Late IOL–Bag Complex Dislocation

One of the classic late complications of PXS is:

Delayed spontaneous dislocation of the entire IOL–capsular bag complex

often years after apparently uncomplicated cataract surgery.

This occurs because zonular degeneration continues after surgery.

Cataract Surgery Does Not Cure PXS

Removing the lens eliminates the classic lens-capsule deposits but:

Pseudoexfoliation is a systemic/anterior segment fibrillopathy and does not disappear after cataract extraction.

Glaucoma and zonular complications may still occur.

Glaucoma Surgery

If medications and SLT do not achieve target IOP, options include:

• Trabeculectomy
• Glaucoma drainage device
• Selected MIGS procedures
• Cyclophotocoagulation in refractory disease

Trabeculectomy

Trabeculectomy can achieve:

• Low target IOP

and remains important in:

• Advanced PXG
• Rapid progression
• Eyes requiring substantial pressure lowering

Glaucoma Drainage Devices

Tube shunts are useful when:

• Trabeculectomy is likely to fail
• Prior filtering surgery has failed
• Conjunctival/scarring factors favor a tube

MIGS

MIGS may be considered in:

• Mild to moderate PXG
• Particularly when combined with cataract surgery

However, for advanced disease requiring very low IOP:

MIGS may be insufficient.

Cyclophotocoagulation

Cyclodestructive procedures may be considered in:

• Refractory glaucoma
• Eyes with poor visual potential
• Selected seeing eyes using modern controlled techniques

Routine Laboratory Testing

Routine laboratory evaluation for:

• Homocysteine
• Vitamin levels

is not recommended solely because PXS is present.

Historical reports of hyperhomocysteinemia have not established a role for routine screening or supplementation.

Systemic Screening

There is currently no standard recommendation for routine:

• Cardiac imaging
• Vascular screening
• Hearing testing

solely because of PXS.

Systemic evaluation should be based on ordinary clinical indications.

Follow-Up – PXS Without Glaucoma

Patients with PXS but no glaucoma generally require:

At least annual ophthalmic follow-up

with:

• IOP
• Optic nerve evaluation
• Gonioscopy when appropriate
• OCT/visual fields according to risk

Closer follow-up is appropriate if:

• IOP is elevated
• Disease is markedly asymmetric
• Optic nerve is suspicious

Follow-Up – PXG

PXG should be monitored according to severity.

Visits may range from approximately:

• Every few months in active/advanced disease
• Less frequently when mild and stable

Monitor:

• IOP
• Optic nerve
• OCT
• Visual fields
• Treatment adherence
• Cataract/lens stability

Prognosis

PXS without glaucoma may remain stable for many years.

Once glaucoma develops:

PXG often behaves more aggressively than POAG.

Poor prognostic features include:

• Very high IOP
• Marked IOP fluctuation
• Advanced damage at diagnosis
• Poor follow-up
• Inadequate treatment

Complications

Important complications include:

• Pseudoexfoliative glaucoma
• Rapid glaucomatous field loss
• Poor pupillary dilation
• Zonular weakness
• Lens subluxation
• Cataract-surgery complications
• Late IOL–bag dislocation
• Corneal endothelial decompensation
• Chronic angle closure in selected eyes

Ophthalmology Pearls

• Pseudoexfoliation syndrome is an age-related fibrillopathy with abnormal extracellular material deposited on the lens, iris, zonules, corneal endothelium, and trabecular meshwork.
• The classic anterior lens appearance is central plaque + clear intermediate zone + peripheral granular ring after dilation.
• Look for poor dilation, peripupillary transillumination defects, loss of pupillary ruff, dense angle pigmentation, and Sampaolesi line.
• LOXL1 is the strongest genetic association, but routine genetic testing is not clinically useful.
• PXS is often bilateral but strikingly asymmetric.
• The major complications are glaucoma and zonular weakness.
• PXG is usually an open-angle glaucoma with higher IOP, greater fluctuation, and faster progression than typical POAG.
• SLT can be an effective first-line or adjunctive therapy, but use cautious energy in heavily pigmented angles because of post-laser IOP spikes.
• Cataract surgery is more difficult because of small pupil and weak zonules.
• A CTR can support the capsular bag but does not eliminate the risk of late IOL–bag complex dislocation.
• Cataract extraction does not cure pseudoexfoliation; glaucoma and zonular degeneration may continue afterward.
• Peripupillary transillumination favors PXS, whereas radial midperipheral transillumination favors pigment dispersion syndrome.
• Routine homocysteine testing or vitamin supplementation is not recommended solely because of PXS.
• Patients with PXS require long-term surveillance because conversion from apparently uncomplicated PXS to ocular hypertension or glaucoma can occur over time.