ANATOMY AND PHYSIOLOGY OF REPRODUCTIVE SYSTEM.pptx
Pigmentary glaucoma - Dr Shylesh B Dabke
1. Pigment Dispersion Syndrome/
Pigmentary Glaucoma
Dr shylesh B dabke
Glaucoma Fellow
Aravind Eye hospital
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2. Overview
Pigment Dispersion syndrome(PDS)
Abnormal amount 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, Sugar briefly 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.
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
8. Mechanical Abrasion Theory
▪ D G Campbell
▪ This theory is based on finding of slit like trans illumination
defect on iris.
9. Slit like trans illumination 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 reverse pupillary 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
Premature degeneration 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
There appears 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 of iris 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 appears to 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.
18.
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*
31. Medical Miotics
Physical
activity
Laser
Trabeculoplasty
Treatment
• Similar to 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 of PDS
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 pupil becomes small & lens becomes thicker
Decreased iridozonular contact
Decreased dispersion
Occasionally glaucoma may “Burn Out”
35. Look carefully for PDS/PG in patients who present as
Normal Tension Glaucoma
Look for
“Pigment Reversal”
Editor's Notes
However autosomal dominant and autosomal recessive patterns are also reported
This finding led to
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
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
Iridotomy abolishes this change
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.
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
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
This is particularly useful in black patients as transillumination defects and Trabecular pigmentation in black patients may be misleading
With hypotensive medication though IOP will be controlled, mechanism of continued pigment dispersion is not eliminated