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Pigmentary glaucoma - Dr Shylesh B Dabke
Pigment Dispersion Syndrome (PDS) involves abnormal amounts of pigment released from the iris that deposit throughout the eye. It can sometimes progress to Pigmentary Glaucoma (PG). PDS is more common in young, white, myopic males and has genetic links. Theories for its pathogenesis include mechanical abrasion between the iris and lens zonules or abnormal iris cell degeneration. Over time, PDS can cause increased eye pressure and vision loss from PG if not properly treated with medications, laser procedures, or surgery.
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Pigmentary glaucoma - Dr Shylesh B Dabke
- 1. Pigment Dispersion Syndrome/ PigmentaryGlaucoma Dr shylesh B dabke Glaucoma Fellow Aravind Eye hospital Download and watch in slideshow mode, online viewing will be disgusting
- 2. Overview Pigment Dispersion syndrome(PDS) Abnormalamount of pigments are liberated from posterior surface of iris, which are deposited throughout the anterior and posterior chamber of the eye. Pigmentory Galucoma A type of secondary open glaucoma that develops among patients with PDS.
- 3. History In 1940, Sugarbriefly described one such case with pigment dispersion and glaucoma.(1) In 1949 - Sugar and Barbour(2) - Reported details of this entity - Referred this condition as “Pigmentary Glaucoma” 1.Sugar HS. Concerning the chamber angle. I. Gonioscopy.Am J Ophthalmol 1940;23:853-866. 2. Sugar HS, Barbour FA. Pigmentary glaucoma: a rare clinical entity. Am J Ophthalmol. 1949;32(1):90-92.
- 4. Epidemology Corresponds to 1-1.5%of all Glaucoma. Onset < 40yrs Male : Female – 2:1 More frequent in whites Strong association between Pigmentary Glaucoma and Myopia.
- 5. “Young White MyopicMale”
- 6. ▪ Usually Bilateral ▪No typical Hereditary Pattern – Sporadic ▪ Significant linkage between disease phenotype and genetic markers located on 7q 35-36. ▪ Probability of PDS converting to PG* 10% in 5 years 15% in 15 years * SiddiquiY., Hulzen R.D.T., Cameron J.D., et al:What is the risk of developing pigmentary glaucoma from pigment dispersion syndrome?. Am J Ophthalmol 2003; 135:794-799
- 7. Pathogenesis Anatomical Predisposition - Myopia -Deep AC - Posterior insertion of iris into ciliary body - Mechanical abrasion theory - Abioptrophy theory Pathophysiology
- 8. Mechanical Abrasion Theory ▪D G Campbell ▪ This theory is based on finding of slit like trans illumination defect on iris.
- 9. Slit like transillumination defect Mechanical rubbing between anterior packets of lens zonules & posterior iris in predisposed eyes Cause of pigment dispersion.
- 10. PDS and Myopia This association can be explained with mechanical abrasion theory.
- 11. PDS and reversepupillary block Second & complementary explanation for iris concavity.
- 12. PDS and Blinking Campbell proposed blinking initially deforms the cornea Pushing iris against zonules Transient increase in IOP
- 13. PDS and Accommodation Accommodation in patients with PDS – increased posterior bowing of iris Forward movement of lens – increasing pressure in anterior chamber
- 14. Abiotrophy Theory Prematuredegeneration of cells or tissue, especially when it is due to genetic defect While mechanical abrasion theory explains several clinical features of pigment dispersion syndrome, key gaps in knowledge still remain. Cellular degeneration is supported in pigment dispersion syndrome by two lines of evidence.
- 15. Heritable Component Thereappears to be a clustering of PDS cases in a subset of families GPDS1 has been mapped to chromosome 7 Dominant inheritance pattern Other gene candidates currently are being investigated.
- 16. Microscopic examination ofiris tissue Within tissue disruptions throughout the iris Pigment-containing cells called melanocytes either are missing or have ruptured membranes from which pigment extrudes.
- 17. Mechanical Abrasion Theory Abiotrophy Theory PDS Evidence appearsto be mounting that the two represent two distinct disease processes that have a common endpoint of pigment dispersion. Once pigment is liberated from the iris, it is carried throughout the anterior chamber and is deposited in multiple locations.
- 19. Clinical Features Early- Asymptomatic Episodes of pain/blurred vision with haloes following strenuous exercise Advanced – Loss of central vision Later - Loss of peripheral vision
- 20. Signs Cornea –Krunkenberg Spindle* Ant Chamber -Deep -Posterior bowing of peripheral iris -Pigments in AC Iris – Slit like/Spoke like transillumination defect*
- 21.
- 22. Fine surfacepigment granules that may extend onto the lens Partial loss of pupillary ruff (frill) Heterochromia Anisocoria
- 23. Gonioscopy - Wideopen angle - Mid peripheral iris concavity* - Trabecular hyperpigmentation Lens - Annular ring of pigment on posterior lens surface “Scheie Strip/Zentamayer Ring”* Fundus - Retinal Breaks & Lattice degeneration(20%) - Retinal detachment (6-7%)
- 25. Classic Clinical Triad KrukenbergSpindle Dense trabecular pigmentation Midperipheral iris transillumination defects
- 26. Differential Diagnosis ExfoliationSyndrome Uveitis Pigment dispersion with PCIOL POAG Pigmented Tumors
- 27. Other conditions withpigment dispersion Acute angle closure glaucoma Rhegmatogenous RD Ocular Haemorrhage Trauma(Surgical/nonsurgical)
- 28. Conditions with iristrans-illumination defects Albunism
- 29. Mid peripheral /Peripupillary Homogenous / Patchy <40 / >60 Absent / Present PDS vs Pseudoexfoliation syndrome Trans- illumination defect TM Pigmenta - tion Age Granular deposits
- 30. Investigation UBM –Posterior iris insertion Iris concavity Iridozonular contact
- 31. Medical Miotics Physical activity Laser Trabeculoplasty Treatment • Similarto POAG • Rx typically begins with medical therapy • All ocular hypotensive medications are effective • PG Analogues are drug of choice* • Theoretically of benefit • Decreases iridozonular contact • Facilitates aqueous outflow • Disadvantage – Exacerbation of myopia Precipitate RD in Myopia Not well tolerated by young patients • Alfa adrenergic antagonist thymoxamine produces miosis without cyclotropia • Exercise increases pigment dispersion and causes IOP spike* • If significant pressure rise is observed, 0.5% Pilocarpine during exercise may be beneficial • Heavy trabecular pigmentation allows increased absorption of laser energy • In turn allowing lower energy level for trabeculoplasty • Starting with 300mW per spot if using ALT and 0.4mJ per spot if using SLT • Ritch et al reported 80% success rate at 1yr followup • Trabeculoplasty responds well initially but IOP control tends to decline wit time and surgery is in effective in patients who are older or who had glaucoma for a long time
- 32. Laser Iridotomy Trabeculectomy • Theoretical effects– - Relives the reverse pressure gradient - Relieves posterior bowing of peripheral iris - Relieves rubbing - Reduces liberation of pigment - Allows meshwork to clear pigment & recover normal outflow function (if changes are not already irreversible) • When medical therapy and laser trabeculoplasty have failed to adequately control IOP • Filtration surgery is usually successful • Use of adjunctive antimetabolites may improve surgical outcome • Higher percentage of patients with pigmentary glaucoma than POAG and men appear to require it at a earlier stage. • Success rates are similar to POAG. • Trabeculectomy in young myopic patients warrants extra care - prone for Hypotony Maculopathy
- 33. Temporal Evolution ofPDS Conversion of PDS to Pigmentary Glaucoma (Slow & may take years) Slow spontaneous resolution Irreversible damage to angle Transillumination defect may disappear IOP may return to normal Trabecular pigmentation may decrease Pigment reversal sign “burnt out”
- 34. With age pupilbecomes small & lens becomes thicker Decreased iridozonular contact Decreased dispersion Occasionally glaucoma may “Burn Out”
- 35. Look carefullyfor PDS/PG in patients who present as Normal Tension Glaucoma Look for “Pigment Reversal”
Editor's Notes
- #7 However autosomal dominant and autosomal recessive patterns are also reported
- #10 This finding led to
- #11 Myopic eyes tend to have a slightly concave iris that potentially could press against the zonules Although myopia could explain some cases of pigment dispersion syndrome, it is insufficient in explaining all instances. Not everyone with myopia has PDS, and not everyone with PDS has myopia
- #12 In reverse pupillary block, pressure in the anterior chamber of the eye exceeds that of the posterior chamber. The increased pressure forces the iris over the lens, where it acts like a ball valve in the pupillary opening, preventing the return of aqueous humor to the posterior chamber. As pressure continues to increase, it causes a backward bowing of the iris that accentuates contact between it and the Zonules of Zinn. In normal eyes iris zonular contact is rare
- #14 Iridotomy abolishes this change
- #15 Primary among these is that liberation of iris pigment can occur in eyes that are not myopic and for which there is little or no evidence of zonule abrasion. For this reason, thinking about PDS has expanded to include the abiotrophy theory.
- #21 Doesn’t impair vision, doesn’t damage corneal endothelium Difficult to see in dark thick iris stroma Infrared video graphic technique have been developed for TID
- #23 Pigment granule dispersion on iris stroma may make iris progressively darker creating heterochromia in asymmetric cases. Anisocoria – Iris with more transillumination defect will have a dilated pupil The iris heterochromia and anisocoria of PDS may mimic Horner syndrome
- #24 This is particularly useful in black patients as transillumination defects and Trabecular pigmentation in black patients may be misleading
- #32 With hypotensive medication though IOP will be controlled, mechanism of continued pigment dispersion is not eliminated