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av bup BMC Ophthalmology
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tT"f Research article Open Access
8@/MrEOW# Comparison of age-specific cataract prevalence in two
DWS#q|j`" population-based surveys 6 years apart
3oV2Ek<d Ava Grace Tan†, Jie Jin Wang*†, Elena Rochtchina† and Paul Mitchell†
z.^_;Vql_ Address: Centre for Vision Research, Westmead Millennium Institute, Department of Ophthalmology, University of Sydney, Westmead Hospital,
LqLhZBU9 Westmead, NSW, Australia
OAaLCpRp Email: Ava Grace Tan -
ava_tan@wmi.usyd.edu.au; Jie Jin Wang* -
jiejin_wang@wmi.usyd.edu.au;
n#sK31;yb Elena Rochtchina -
elena_rochtchina@wmi.usyd.edu.au; Paul Mitchell -
paul_mitchell@wmi.usyd.edu.au X\kWJQ: * Corresponding author †Equal contributors
S`Z[MNY Abstract
,H_d#Koa. Background: In this study, we aimed to compare age-specific cortical, nuclear and posterior
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B|! subcapsular (PSC) cataract prevalence in two surveys 6 years apart.
h; 6G~D Methods: The Blue Mountains Eye Study examined 3654 participants (82.4% of those eligible) in
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cross-section I (1992–4) and 3509 participants (75.1% of survivors and 85.2% of newly eligible) in
qP-_xpu]R cross-section II (1997–2000, 66.5% overlap with cross-section I). Cataract was assessed from lens
"wCx]{Di photographs following the Wisconsin Cataract Grading System. Cortical cataract was defined if
v\E6N2.S cortical opacity comprised ≥ 5% of lens area. Nuclear cataract was defined if nuclear opacity ≥
vdigw.=z Wisconsin standard 4. PSC was defined if any present. Any cataract was defined to include persons
{|'NpV who had previous cataract surgery. Weighted kappa for inter-grader reliability was 0.82, 0.55 and
B4* uS ( 0.82 for cortical, nuclear and PSC cataract, respectively. We assessed age-specific prevalence using
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c<nYdK? an interval of 5 years, so that participants within each age group were independent between the
_5S||TuNS two surveys.
uAs!5h Results: Age and gender distributions were similar between the two populations. The age-specific
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B*D*w prevalence of cortical (23.8% in 1st, 23.7% in 2nd) and PSC cataract (6.3%, 6.0%) was similar. The
_2{2Xb prevalence of nuclear cataract increased slightly from 18.7% to 23.9%. After age standardization,
_SkiO}c8 the similar prevalence of cortical (23.8%, 23.5%) and PSC cataract (6.3%, 5.9%), and the increased
&DjA?0`J prevalence of nuclear cataract (18.7%, 24.2%) remained.
u}P:9u&h6X Conclusion: In two surveys of two population-based samples with similar age and gender
fhyoSRLR: distributions, we found a relatively stable cortical and PSC cataract prevalence over a 6-year period.
W.%p{wB| The increased prevalence of nuclear cataract deserves further study.
B@S~v+Gr Background
YkE_7r(1 Age-related cataract is the leading cause of reversible visual
5V~vND*
s impairment in older persons [1-6]. In Australia, it is
DWEDL[{ estimated that by the year 2021, the number of people
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215 affected by cataract will increase by 63%, due to population
^cE {Uv aging [7]. Surgical intervention is an effective treatment
yo(MJ^=d for cataract and normal vision (> 20/40) can usually
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be restored with intraocular lens (IOL) implantation.
]')y(_{ Cataract surgery with IOL implantation is currently the
fwmXIpteK most commonly performed, and is, arguably, the most
C]fX=~?bGQ cost effective surgical procedure worldwide. Performance
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0$M0 Published: 20 April 2006
PVIZ
Y^64 BMC Ophthalmology 2006, 6:17 doi:10.1186/1471-2415-6-17
f*ABIm Received: 14 December 2005
q/Vl>t Accepted: 20 April 2006
+FAxqCkA This article is available from:
http://www.biomedcentral.com/1471-2415/6/17 {p$@)b © 2006 Tan et al; licensee BioMed Central Ltd.
sCP|d`' This is an Open Access article distributed under the terms of the Creative Commons Attribution License (
http://creativecommons.org/licenses/by/2.0),
,0ilNi> which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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2knSS BMC Ophthalmology 2006, 6:17
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KeB??1S of this surgical procedure has been continuously increasing
+IWf~|s in the last two decades. Data from the Australian
` AD}6O+x Health Insurance Commission has shown a steady
wjZ Q.T! increase in Medicare claims for cataract surgery [8]. A 2.6-
R'6(eA[K fold increase in the total number of cataract procedures
+> d;%K from 1985 to 1994 has been documented in Australia [9].
HG< z,gE
2 The rate of cataract surgery per thousand persons aged 65
^TjC years or older has doubled in the last 20 years [8,9]. In the
=
Ezg3$
%- Blue Mountains Eye Study population, we observed a onethird
U$y wO4. increase in cataract surgery prevalence over a mean
xf8[&? 6-year interval, from 6% to nearly 8% in two cross-sectional
_~{J."q population-based samples with a similar age range
w{lj'3z I [10]. Further increases in cataract surgery performance
8DMqjt3B would be expected as a result of improved surgical skills
8~yP?#p and technique, together with extending cataract surgical
08{^Ksg benefits to a greater number of older people and an
'Z=_zG/RX increased number of persons with surgery performed on
jUl_ToX both eyes.
);yZyWDV Both the prevalence and incidence of age-related cataract
Y<kz+d,C link directly to the demand for, and the outcome of, cataract
{Rb;1 eYj surgery and eye health care provision. This report
CB,2BTtRE aimed to assess temporal changes in the prevalence of cortical
oM^vJ3 and nuclear cataract and posterior subcapsular cataract
3-6MGL9 (PSC) in two cross-sectional population-based
kOdpW surveys 6 years apart.
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