BioMed Central
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r&XxF> BMC Ophthalmology
t"6u Research article Open Access
?W&ajH_T Comparison of age-specific cataract prevalence in two
W7IAW7w8U population-based surveys 6 years apart
@_h=,g#@ Ava Grace Tan†, Jie Jin Wang*†, Elena Rochtchina† and Paul Mitchell†
&7c #i Address: Centre for Vision Research, Westmead Millennium Institute, Department of Ophthalmology, University of Sydney, Westmead Hospital,
'RR,b*Ql Westmead, NSW, Australia
t1aKq)? Email: Ava Grace Tan -
ava_tan@wmi.usyd.edu.au; Jie Jin Wang* -
jiejin_wang@wmi.usyd.edu.au;
D6EqJ
,~ Elena Rochtchina -
elena_rochtchina@wmi.usyd.edu.au; Paul Mitchell -
paul_mitchell@wmi.usyd.edu.au M/}i7oS] * Corresponding author †Equal contributors
r\}
O{ZO Abstract
QwI HEmdM Background: In this study, we aimed to compare age-specific cortical, nuclear and posterior
jgw+c3^R_ subcapsular (PSC) cataract prevalence in two surveys 6 years apart.
j*_#{niy: Methods: The Blue Mountains Eye Study examined 3654 participants (82.4% of those eligible) in
SN#N$] y5s cross-section I (1992–4) and 3509 participants (75.1% of survivors and 85.2% of newly eligible) in
z'EphL7r cross-section II (1997–2000, 66.5% overlap with cross-section I). Cataract was assessed from lens
`P;uPQDzZ3 photographs following the Wisconsin Cataract Grading System. Cortical cataract was defined if
*0 ;| cortical opacity comprised ≥ 5% of lens area. Nuclear cataract was defined if nuclear opacity ≥
|%=c<z+8 Wisconsin standard 4. PSC was defined if any present. Any cataract was defined to include persons
d,t'e? who had previous cataract surgery. Weighted kappa for inter-grader reliability was 0.82, 0.55 and
OEHw% 0.82 for cortical, nuclear and PSC cataract, respectively. We assessed age-specific prevalence using
sAPYQ an interval of 5 years, so that participants within each age group were independent between the
?&.Eg^a" two surveys.
RD*.n1N1 Results: Age and gender distributions were similar between the two populations. The age-specific
ATI2 prevalence of cortical (23.8% in 1st, 23.7% in 2nd) and PSC cataract (6.3%, 6.0%) was similar. The
<*$IZl6I prevalence of nuclear cataract increased slightly from 18.7% to 23.9%. After age standardization,
0ac'<;9]zP the similar prevalence of cortical (23.8%, 23.5%) and PSC cataract (6.3%, 5.9%), and the increased
'S;l" prevalence of nuclear cataract (18.7%, 24.2%) remained.
L$f:D2Ei Conclusion: In two surveys of two population-based samples with similar age and gender
T-lHlm distributions, we found a relatively stable cortical and PSC cataract prevalence over a 6-year period.
n4Eqm33 The increased prevalence of nuclear cataract deserves further study.
WiclG8l Background
m=%WA5c? Age-related cataract is the leading cause of reversible visual
{!7 ^
w impairment in older persons [1-6]. In Australia, it is
F /% 5 r{ estimated that by the year 2021, the number of people
?hwT{h affected by cataract will increase by 63%, due to population
iKuSk~ aging [7]. Surgical intervention is an effective treatment
X{bqG]j for cataract and normal vision (> 20/40) can usually
-+=+W be restored with intraocular lens (IOL) implantation.
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