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Pigment Dispersion Syndrome/Pigmentary Glaucoma

ROUTINE — Glaucoma

Symptoms

Presentation

  • Mostly asymptomatic (detected on routine exam).
  • Classic: Blurred vision, eye pain, and colored halos after vigorous exercise.
  • Occurs primarily in young, myopic (near-sighted) men (age 20–45).
  • Typically bilateral but often asymmetric.
  • High risk of floaters/flashes due to associated lattice degeneration.

Clinical Findings

Mechanical hallmark

  • Reverse pupillary block: Peripheral iris bows posteriorly, rubbing against zonules.
  • Concavity: "Swept-back" iris contour seen on UBM or AS-OCT.

The cardinal signs

  • Krukenberg spindle: Vertical band of pigment on the corneal endothelium.
  • Iris TIDs: Radial, spoke-like transillumination defects in the mid-periphery.
  • Scheie stripe (Zentmayer ring): Pigment on the posterior lens equator (pathognomonic).

Gonioscopy

  • 3–4+ dense, homogeneous trabecular meshwork (TM) pigmentation 360°.
  • Sampaolesi line: Pigment band anterior to Schwalbe’s line.

Etiology

Pathophysiology

  • Friction between the posterior iris pigment epithelium and lens zonules liberates pigment.
  • Aqueous flow carries pigment into the anterior chamber, where it clogs the TM.

Statistics

  • ~30–50% of patients with Pigment Dispersion Syndrome (PDS) convert to glaucoma.
  • Conversion risk is highest in young males with high baseline IOP.

Red Flags

  • Post-exercise IOP spike: Sudden blur or pain after running/basketball (pigment bolus).
  • Rapid field progression: Common in young patients; requires aggressive management.
  • Lattice degeneration: Mandatory 360° peripheral exam to rule out retinal tears/RD.
  • Unilateral presentation: Reconsider diagnosis (suspect uveitis or IOL chafe).

Investigations

Clinical evaluation

  • Gonioscopy: To confirm heavy, uniform TM pigmentation.
  • Slit-lamp red reflex: To visualize mid-peripheral iris transillumination defects.
  • Careful IOP check: Consider pre- and post-exercise measurements if symptomatic.

Glaucoma staging

  • Automated perimetry (HVF) and OCT RNFL/GCC for baseline damage assessment.

Peripheral retina

  • Dilated exam with scleral depression (mandatory for all myopic PDS patients).

Treatment

Medical management

  • Standard drops: Prostaglandin analogs or aqueous suppressants (first-line).
  • Pilocarpine (miotics): Theoretically ideal (flattens iris), but poorly tolerated in youths.

Laser therapy

  • SLT (Selective Laser Trabeculoplasty): Highly effective due to heavy pigment; use low energy.
  • LPI (Laser Peripheral Iridotomy): No longer routine; may benefit young patients with severe concavity.

Surgical

  • Trabeculectomy or tube shunt for refractory cases failing medical/laser therapy.

Clinical Pearl

A young myopic male with exercise-triggered blur and a Krukenberg spindle has pigment dispersion — warn him about gym-induced IOP spikes and consider pre-exercise pilocarpine.

Differential Diagnosis

  • • Pseudoexfoliation (older patients, pigment on anterior lens, patchy TM pigment).
  • • Uveitis (pigment on endothelium but associated with cells/flare/PI).
  • • Iris chafe (post-surgical, secondary to sulcus-placed IOL).
  • • Bilateral acute depigmentation of the iris (BADI).

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