Lec.8: Pseudo-exofliation Syndrome and Glaucoma Flashcards
where is the dandruff-like material found histologically?
lens epithelium and capsule, pupillary margin, ciliary epithelium, iris pigment epithelium, iris stroma, iris blood vessels and sub-conjunctival tissue
what percentage of XFS (exfoliation syndrome) develop into XFG (exfoliation glaucoma)?
30%
what is the prevalence of XFS?
it can affect ANY population
what leads to increased incidence of XFS?
old age and being female
what characteristic of XFS corresponds to the pupil?
central disc
in XFS what does the clear zone represent?
removal of material by iris movement
why do deposits appear again in the peripheral granular zone of XFS?
due to undisturbed accumulation of deposits
where else can XFS material be found? and what impact might it have on the lens?
zonules. XFS material on zonules can lead weaker zonules and eventual lens movement
what is lens movement referred to as?
phacodonesis
what is a potential post-cataract surgery complication with XFS?
production of XFS material continues to weaken zonules and leads to displacement (subluxation) of IOL.
why might it be hard to dilate a patient with XFS?
due to deposits on iris stroma muscle and degeneration of sphincter and dilator
what is the result of blocked iris vessels in XFS?
hypoperfusion and NVI
why would you check IOP in a patient with XFS after dilation?
dilation may result in acute IOP rise
whats is pigment deposition on Schwalbe’s line referred too?
Sampaolesi’s line
how does pigmentation in XFS differ from pigmentation in PDS?
XFS= uneven pigmentation PDS= even pigmentation
how is the cornea affected by XFS?
endothelium may show some adhering XFS material and may see lower cell density and morphological cell changes
what happens to endothelial cells in exfoliation keratopathy?
reduced count (800-1500 cells/mm^2) and changes in cell size/ shape
what happens to descemets membrane in exfoliation keratopathy?
irregular thickening
what procedure might be needed in later stages of exfoliation keratopathy?
penetrating keratoplasty
in XFS, what percentage of cases are unilateral in caucasians?
48%
in XFS, what percentage of cases are unilateral in Japanese?
85%
what percentage of XFS cases are missed by observers?
15%
(T/F)blood flow in patients with exfoliative glaucoma (XFG) is lower than patients with exfoliative syndrome (XFS)?
true
what systemic diseases result from XFS?
elevated plasma homocysteine levels and mild sensory hearing loss
XFS leads to an increase of morbidity (co-occurrence) of what diseases?
cardiovascular, cerebrovascular and Alzheimer’s
when adjusting for IOP, is there a change in the relationship between XFS and glaucoma?
no
how is blood flow disturbed in exfoliative glaucoma?
exfoliation material found in posterior ciliary artery and vortex veins
what is the risk of developing glaucoma if an XFS patient has ocular hypertension?
3.7 times greater
how does the degree of pigmentation of exofilation material in the angle correlate with IOP?
more pigment= higher IOP
in 10 years, what percentage of XFS patients convert to XFG?
32%
on average what IOP value do patients with XFG tend to exceed?
35 mmHg
what is the fluctuation in IOP for 50% of patients with normotensive XFS?
5 mmHg
what is the fluctuation in IOP for 10% of patients with normotensive XFS?
10 mmHg
what are the risk for an XFS patient prior to cataract surgery?
capsular tear, vitreous loss and dislocation of IOL
why is medical therapy not very effective in exfoliation glaucoma?
high mean IOP, high IOP spikes and IOP fluctuations greater
what is the percentage of progression in XFG in patients with a mean IOP less than 17 mmHg?
28%
what is the percentage of progression in XFG in patients with a mean IOP greater than 20 mmHg?
70%
why are miotics often used for treatment?
pupil is fixed so less pigment dispersion; May help outflow and removal of materials
what does ALT (argon laser trabeculoplasty ) do?
creates a hole in the TM to let debris out to help lower IOP
what does SLT (Selective laser trabeculoplasty) do?
selectively targets intracellular melanin in TM
describe the thermal damage and disruption in SLT?
shorter exposure time, very low power and wide area of application decreased
which laser treatment is usually able to be repeated?
SLT (doesn’t cause any burn)
from left to right, name the three regions shown in this picture?
central disc, clear zone and peripheral granular zone
what is this image showing?
loss of pupillary ruff
describe the three types of keratopathy shown?
(form left to right): normal control, PDS and fellow eye of XFS
