Pigment dispersion syndrome

glaucoma /ophthalmology

1. Pigment Dispersion Syndrome Dr. Aditi Singh

2. Described by : Sugar and Brown 1949

3. 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

4. E pidemiology Young Myopic Male Experiences blurry vision or eye pain after exercise

5. 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,”

6. Accumulation of pigment granules in the intertrabecular meshwork Increases resistance of aqueous egress elevating IOP Elevating IOP.

7. 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.

8. Clinical features: Myopes , young males,caucacians , positive family history Cornea: Corneal endothelial pigment appears as a central, vertical, brown band ( Krukenberg spindle)

9. Iris: Loss of iris pigment appears as a midperipheral , radial, slit-like pattern of transillumination defects. Difficult to appreciate in dark iris.

10. 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

11. Posterior segment: lattice degeneration - 20 % of patients retinal breaks- 11.7 % rhegmatogenous retinal detachments requiring surgery may occur in 3.3 % Optic nerve examination: Size , PPA, RNFL defect, disc h’ges , NRR thinning

12. 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 )

13. 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

14. . 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

15. 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 iridozonular contact. Tension over the scleral spur, miotics increase aqueous outflow through the trabecular meshwork. Low-concentration pilocarpine . Peripheral retina should be examined carefully

16. 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.

17. 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.

18. 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

19. Trabeculectomy : Not responding to medical / laser therapy. MMC to be used in lower concentration for lesser time. Outcomes comparable /better than of POAG