and Systemic Pseudoexfoliation Syndrome
knowledge of this condition continues to expand, allowing us to identify new types
W. DUL, O.D., M.S., F.A.A.O.
In 2007, the Optometric Glaucoma Society (OGS)
will provide OM with expert authors who will discuss therapies, epidemiology, case
studies and other current issues in glaucoma management. For additional information
on the Society, contact the OGS through the Web site optometricglaucomasociety.org.
The views expressed in this article are the author's and do not necessarily represent
the views of the OGS.
open angle glaucoma is by far the most common form of all of the glaucomas. The
secondary glaucomas represent a group of disorders, which, unlike POAG, have a recognizable
cause of elevation of intraocular pressure (IOP). You must recognize secondary glaucomas,
the treatment and prognosis often differ from POAG.
Pseudoexfoliative glaucoma (PXG) began to appear in scientific
literature in the early 1900s. Pseudoexfoliation (PEX) syndrome is known as an age-related
disorder of the extracellular matrix. It is often diagnosed at the slit lamp by
the presence of abnormal fibrillar deposits on ocular structures that line the aqueous-bathed
surfaces of the anterior segment.1 These histologic changes are, to varying
degrees, responsible for the co-morbid intraocular findings and surgical complications
associated with PXG.
This condition has worldwide distribution, but is more common
in certain populations. It represents more than half of all glaucoma cases in patients
of Scandinavian descent .2 It's not uncom- mon in patients of Russian
descent and is much less common in African-American and Eskimo populations.3
In the United States, the prevalence rate ranges from approximately 5% to 15% of
all glaucoma cases.4 This condition is generally more common in women
and the elderly.1
of Early Stages and Clinical and Surgical Complications of Pseudoexfoliation (PEX)
EARLY CLINICAL SIGNS
ciliary body, and
Diffuse precapsular layer
PEX deposits on zonules
Angle-closure glaucoma due to pupillary and ciliary block
Decentration of the lens implant
Anterior capsule fibrosis
Peripapillary atrophy and iris sphincter region
Melanin dispersion associated with pupillary dilation
Poor mydriasis, asymmetric pupil sizes
Blood-aqueous barrier defects, pseudouveitis
Anterior chamber hypoxia
Intra- and post-operative hyphema
Prolonged blood-aqueous barrier breakdown
Posterior synechiae/pupillary block
Marked asymmetry of IOP
Marked IOP rise after pupillary dilation
hypertension Open-angle glaucoma
Postoperative IOP rise
We do not fully understand the etiology of this condition. Pseudoexfoliation
syndrome is a systemic disease associated with abnormalities of the basement membrane
in epithelial cells, which are found throughout the body (intraocular lens, lungs,
skin, liver, heart, blood vessels, extraocular muscle, meninges, etc). Despite this
distribution, its clinical manifestations are limited to the eye. Speculation remains
regarding the role of genetics and the patient's environment. However, these factors
have not been fully elucidated.
Some reports show patients with pseudoexfoliation have higher
levels of homocysteine (a sulfur-containing amino acid), which may be a risk factor
for cardiovascular disease due to its direct toxic effect on arteries, interference
with clotting and oxidation of low-density lipoproteins.1,5 After adjusting
for age and other variables, it's unclear whether an association between pseudoexfoli-
ation syndrome and cardio/cerebrovascular morbidity exists.
Patients with PEX are much more likely to develop glaucoma when
compared with age-matched groups without this condition.5 The accumulation
of pseudoexfoliative material in the trabecular meshwork and the
juxtacanalicular tissue next to Schlemm's canal leads to obstruction of aqueous
leaving the eye and increases IOP.6
PEX typically presents unilaterally and, when high IOP is present,
it is usually higher when compared with POAG. Diurnal IOP at all time intervals
tends to be higher on average in patients with PXG when compared with age-similar
norms.7 In addition, the range, maximum, minimum and variance of diurnal
IOP all tend to be higher. In one recent study, more than half of PXG patients had
diurnal fluctuations >5mm Hg, and 10% had fluctuations >10mm Hg.8
Over time, the contralateral eye has an approximately 40% chance
of developing signs of pseudoexfoliation.9 This condition is more common
in patients over the age of 60 and its incidence increases with age. Unlike pigmentary
dispersion glaucoma, which shares some of the same clinical signs, it's uncommon
in patients younger than age 40.10
PXG syndrome is diagnosed during the anterior segment ex-am with
a biomicroscope. Pseudoexfoliative material is visible on the border of the pupil.
The classic appearance is on the anterior capsule of the intraocular lens. This
concentric circular pattern is comprised of a central circle of material (1mm to
2.5mm in diameter) surrounded by an apparently material-free band of anterior capsule,
most likely produced by contact between the posterior iris and the lens during normal
papillary function. This contact produces an apparently smooth surface on the anterior
capsule and the potential for liberation of pigment from the posterior iris into
the anterior cham- ber. Beyond this, a second zone of material appears to surround
the remainder of the lens capsule.
There are three treatment options for PXG:
Medical. Because IOP can be high during the course of this
condition, check the IOP of pseudoexfoliation syndrome patients at regular intervals. Once you establish a diagnosis of PXG, begin treatment as you
would for primary open angle glaucoma. Monitor the efficacy of IOP lowering medica-
tions, as PXG is typically a more aggressive form of glaucoma that can progress
more rapidly than POAG despite previous control.7 Like pigmentary glaucoma,
the use of miotics has some theoretical advantages in the care of these patients.
However, in practice they are used less often than conventional medications due
to the quality of life issues associated with miosis, the q.i.d. dosing regimen,
the risk of retinal detachment, posterior synechia and the need to discontinue miotics
for dilated fundus examinations and visual fields.
Laser. In general, patients with PXG respond well and often
better than their POAG counterparts, to argon laser trabeculoplasty, at least during
its initial application. Unfortunately, within five years, nearly half of these
patients are back to baseline IOPs. In addition, as many as 20% of these patients
will have a rapid sustained increase in IOP within two years following the procedure.11
Surgical Care. Due to the aggressive nature of this condition, trabeculectomy and/or combined cataract/trabeculectomy is more common in this population
compared with their POAG counterparts. However, surgical complications are also
PXG patients who don't manifest high IOP or structural/functional
changes still require regu- lar assessments due to the potentially rapid and high
levels of IOP increases associated with this condition.
1. Ritch R., Schlotzer-Schrehardt U., Exfoliation syndrome, Surv
Ophthalmol. 2001 Jan-Feb;45:265-315.
2. Ringvold A. Epidemiology of glaucoma in northern Europe. Eur
J Ophthalmol. 1996 Jan-Mar;6(1):26-9.
3. Cashwell LF Jr, Shields MB. Exfoliation syndrome in the southeastern
U.S. Prevalence in open-angle glaucoma and non-glaucoma populations. Acta Ophthalmol.
4. Karger RA, Jeng SM, Johnson DH et al. Estimated incidence of
pseudoexfoliation syndrome and pseudoexfoliation glaucoma in Olmsted County, Minnesota.
J Glaucoma. 2003 Jun; 12(3): 193-7.
5. Leibovitch I, Kurtz S, Shemesh G, et al. Hyperhomocystinemia
in pseudoexfoliation glaucoma. J Glaucoma. 2003 Feb;12(1):36-9.
6. Ritch R. Exfoliation syndrome the most common identifiable
cause of open-angle glaucoma. J Glaucoma. 1996; 3:176-178.
7. Schlotzer-Schrehardt U, Naumann GO. Ocular and systemic pseudoexfoliation
syndrome. Am J Ophthalmol. 2006 May;141(5):921-937.
8. Konstas AGP, Stewart WC, Stromann GA, et al. Clinical presentation
and initial treatment patterns in patients with exfoliation glaucoma versus primary
open-angle glaucoma. Ophthalmol Surg Laser. 1997 Feb;28:111-117.
9. Altintas O, Yuksel N, Karabas VL, et al. Diurnal intraocular
pressure variation in pseudoexfoliation syndrome. Eur J Ophthalmol. 2004 Nov-Dec;14(6):495-500.
10. Puska PM. Unilateral exfoliation syndrome: conversion to bilateral
exfoliation and to glaucoma: a prospective 10 year follow-up study. J Glaucoma.
11.Threlkeld AB, Hertzmark E and Sturm RT, et al. Comparative
study of efficacy of argon laser trabeculoplasty for exfoliation and primary open
angle glaucoma. J Glaucoma. 1996 Oct;5:311-16.
12. Jacobi PC, Dietlein TS, Kriegl-stein GK. Comparative study
of trabecular aspiration vs. trabeculectomy in glaucoma triple procedure to treat
pseudoexfoliation glaucoma. Arch Ophthalmol 1999 Oct; 117(10): 1311-8.
Dr. Dul is
chair of the department of clinical sciences and director of the Glaucoma Institute
at the State University of New York (SUNY) Optometry. He is also a founding member
of OGS and sees patients in both academic and private settings.
Optometric Management, Issue: January 2007