Pigment Dispersion Syndrome

 Gonioscopy demonstrates a noticeable band of dark pigment (delineating the pigment-laden trabecular meshwork).

  • Mild pigment dispersion can be observed as a normal aging process
  • Pigmentary glaucoma results when deposition of excessive pigment in the trabecular meshwork (as a result of liberation of pigment from the posterior iris epithelial surface in response to rubbing against the lens zonules) causes elevated intraocular pressure and subsequent optic disc damage

Clinical features:

  • Symptoms may be asymptomatic or present as an intermittent or rapid onset of elevated intraocular pressure associated with corneal edema, ocular pain, intermittent blurring of vision or halos
  • Signs:
    • Radial periphery transillumination defects of the iris
    • Krukenberg spindle: a vertically oriented deposition of pigment on the posterior endothelial surface of cornea
    • A band of dark brown or black pigment along the trabecular meshwork (on gonioscopy)
    • Collection of pigment particles on the surface of the iris
    • Dense pigment deposition on the posterior lens surface
    • Posterior or concave bowing of the perpheral iris (on gonioscopy)
    • Differential diagnosis may include the following: exfoliation syndrome, pseudophakia with malpositioned posterior chamber intraocular lens, iris or ciliary body cysts, intraocular pigmentary masses (e.g. melanoma), and uveitis

Management:

  • Observation and close follow-up of patients at risk
  • Medical therapy if glaucoma present (or at risk for glaucoma)
  • Surgical therapy includes:
    • Peripheral laser iridotomy to flatten the iris and eliminate posterior bowing of the iris (thereby minimizing pigment liberation)