Pigment dispersion syndrome

PIGMENT DISPERSION SYNDROME

Dr. Aditi Singh

Described by : Sugar and Brown 1949

Pigment dispersion syndrome (PDS) and pigmentary

glaucoma (PG) :

two successive stages of the same disease process

characterized by –

disruption of the iris pigment epithelium

and deposition of the dispersed pigment granules

throughout the anterior segment

EPIDEMIOLOGY

Young

Myopic

Male

Experiences blurry vision or eye pain after exercise

PATHOPHYSIOLOGY

Concave iris contour that allows apposition of its

posterior surface to the zonular bundles.

Friction between zonules and the peripheral iris - cause

of the pigment liberation.

Reverse pupillary block mechanism may exist : “flap

valve,”

Accumulation of pigment granules in the intertrabecular

meshwork

Increases resistance of aqueous egress elevating IOP

Elevating IOP.

Exercise (jogging, playing basketball, and bouncing

during dancing) can cause the release of pigment

as a result of pupillary movement.

Pharmacologic pupillary dilation - may result in

significant pigment liberation into the anterior

chamber.

This pigment liberation may be accompanied by

IOP increase.

CLINICAL FEATURES:

Myopes, young males,caucacians, positive family history

Cornea: Corneal endothelial pigment appears as a

central, vertical, brown band (Krukenberg spindle)

Iris: Loss of iris pigment appears as a midperipheral,

radial, slit-like pattern of transillumination defects.

Difficult to appreciate in dark iris.

Lens / Zonules : Interrupted lines on the posterior

peripheral surface of the lens – Zentamayer ring or

Scheie’s stripe.

Angle: Wide open.

Heavy dark brown to black pigmentation.

Homogenous .

Prominent inferiorly.

The iris is inserted posteriorly into the ciliary body,

configuration : concave

Posterior segment:

lattice degeneration - 20% of patients

retinal breaks- 11.7%

rhegmatogenous retinal detachments

requiring surgery may occur in 3.3%

oOptic nerve examination:

Size , PPA, RNFL defect, disc h’ges, NRR thinning

TEMPORAL EVOLUTION OF PDS

Conversion of PDS to PG – slow and may take years

slow spontaneous resolution irreversible damage to angle

transillumination defects may disappear,

the IOP may return to normal,

the trabecular meshwork pigmentation may decrease.

Pigment reversal sign ( burned out )

DIFFERENTIAL DIAGNOSIS

Disorders causing anterior segment pigment dispersion :

exfoliation syndrome (XFS),

diabetes,

herpetic eye disease,

iris pigment epithelitis,

radiation,

trauma,

iris pigment epithelial cysts,

ciliary

body cysts,

iris nevus, and

melanoma or melanocytoma of

the anterior and posterior segment

.Features Pseudoexfoliation

syndrome

Pigment dispersion

syndrome

Transillumination

defects

Peripupillary Radial mid peripheral

TM pigmentation Patchy homogenous

Age group > 60 yrs ( older) 20- 30 yrs (younger)

whitish granular

deposits

Present Absent

TREATMENT

The treatment of PDS/PG is aimed at reversing the iris concavity, preventing pigment release, and therefore lowering IOP.

Miotics:

reverses the iris concavity and eliminates iridozonularcontact.

Tension over the scleral spur, miotics increase aqueous outflow through the trabecular meshwork.

Low-concentration pilocarpine.

Peripheral retina should be examined carefully

Prostaglandin analogues: Increasing uveoscleral

outflow.

Agents that lower IOP by reducing aqueous production

hypothetically –

may diminish the rate of clearance of the pigment from

the trabecular meshwork, possibly exacerbating the

disease process.

these agents may inhibit relative pupillary block, which

is therapeutic in PDS.

LASER IRIDOTOMY

Equalizes pressures between the anterior and posterior chambers,

Flattens the iris,

Eliminates iridozonular contact, and

Occasionally decreases further liberation of pigment

Proper patient selection.

Ideally, patients should still be in the pigment liberation stage.

In young patients with iris concavity, active release of pigment and ocular hypertension, LI may be of benefit for years.

Argon laser trabeculoplasty and selective laser

trabeculoplasty

Alternative treatments to lower IOP, mostly in young

pigmentary glaucoma patients.

The success rate of argon laser trabeculoplasty

(ALT) in PG is greater in younger patients than in

older ones and decreases with age

Trabeculectomy :

Not responding to medical / laser therapy.

MMC to be used in lower concentration for lesser

time.

Outcomes comparable /better than of POAG