ABSTRACT
&x0C4Kh Purpose: To quantify the prevalence of cataract, the outcomes
Kd3QqVJBz1 of cataract surgery and the factors related to
.$Bwb/a unoperated cataract in Australia.
M$A#I51 Methods: Participants were recruited from the Visual
.
uR M{Bs Impairment Project: a cluster, stratified sample of more than
/APcL5:= 5000 Victorians aged 40 years and over. At examination
Z^zbWFO]5 sites interviews, clinical examinations and lens photography
v7IzDz6gF were performed. Cataract was defined in participants who
$
[7 Vgs had: had previous cataract surgery, cortical cataract greater
S &JJIFftO than 4/16, nuclear greater than Wilmer standard 2, or
"+|L_iuNQ posterior subcapsular greater than 1 mm2.
by86zX Results: The participant group comprised 3271 Melbourne
H9`
f0(H residents, 403 Melbourne nursing home residents and 1473
~ y;y(4< rural residents.The weighted rate of any cataract in Victoria
J!h^egP was 21.5%. The overall weighted rate of prior cataract
u@=?#a$$ surgery was 3.79%. Two hundred and forty-nine eyes had
U,;xZe had prior cataract surgery. Of these 249 procedures, 49
S#8>ZwQ (20%) were aphakic, 6 (2.4%) had anterior chamber
ALGgAX3t intraocular lenses and 194 (78%) had posterior chamber
l#bAl/c` intraocular lenses.Two hundred and eleven of these operated
s_eOcm eyes (85%) had best-corrected visual acuity of 6/12 or
|}[nH> better, the legal requirement for a driver’s license.Twentyseven
u3ZCT" ! (11%) had visual acuity of less than 6/18 (moderate
GXX+}=b7qO vision impairment). Complications of cataract surgery
&ZJgQ-Pc(m caused reduced vision in four of the 27 eyes (15%), or 1.9%
:
reTJQwr of operated eyes. Three of these four eyes had undergone
xh0 xSqDM intracapsular cataract extraction and the fourth eye had an
TJy4<rb opaque posterior capsule. No one had bilateral vision
4MW ]EQ- impairment as a result of cataract surgery. Surprisingly, no
%<Q*Jf particular demographic factors (such as age, gender, rural
onte&Ed\
residence, occupation, employment status, health insurance
.q;ED`
G status, ethnicity) were related to the presence of unoperated
|L:Cn J cataract.
nr2r8u9r Conclusions: Although the overall prevalence of cataract is
YQ(Po!NI\' quite high, no particular subgroup is systematically underserviced
`/Y+1 aD in terms of cataract surgery. Overall, the results of
M{N(~ql cataract surgery are very good, with the majority of eyes
d^V$Z6*
] achieving driving vision following cataract extraction.
3Wx,oq;4- Key words: cataract extraction, health planning, health
Jb(Y,LO^ services accessibility, prevalence
8SmjZpQ? INTRODUCTION
w+AuMc Cataract is the leading cause of blindness worldwide and, in
:tGYs8UK Australia, cataract extractions account for the majority of all
TbhH&kG)1 ophthalmic procedures.1 Over the period 1985–94, the rate
MagM
ZR of cataract surgery in Australia was twice as high as would be
wu~hqd expected from the growth in the elderly population.1
"="O > Although there have been a number of studies reporting
F $yO the prevalence of cataract in various populations,2–6 there is
Vk}49O<K/ little information about determinants of cataract surgery in
SUdm 0y the population. A previous survey of Australian ophthalmologists
^toAw8A=@0 showed that patient concern and lifestyle, rather
pY}/j;.[ than visual acuity itself, are the primary factors for referral
d;G~hVu for cataract surgery.7 This supports prior research which has
=Hu0v}i/ shown that visual acuity is not a strong predictor of need for
mLwY]2T" cataract surgery.8,9 Elsewhere, socioeconomic status has
@}LZ! y been shown to be related to cataract surgery rates.10
y?z\L To appropriately plan health care services, information is
XGs^rIf needed about the prevalence of age-related cataract in the
VWf %v community as well as the factors associated with cataract
e%6{ME
3 surgery. The purpose of this study is to quantify the prevalence
lrEj/"M of any cataract in Australia, to describe the factors
f~M8A. related to unoperated cataract in the community and to
F9Z@x) describe the visual outcomes of cataract surgery.
>1|g5 METHODS
Vb4;-?s_ Study population
4\2V9F{s Details about the study methodology for the Visual
PEXq:TA Impairment Project have been published previously.11
8b&uU [ Briefly, cluster sampling within three strata was employed to
#Ob]]!y recruit subjects aged 40 years and over to participate.
=!.mGW-Q} Within the Melbourne Statistical Division, nine pairs of
'ZHdV,dd census collector districts were randomly selected. Fourteen
v1.*IV5Y nursing homes within a 5 km radius of these nine test sites
T1
MY X were randomly chosen to recruit nursing home residents.
-T_\f?V8
8 Clinical and Experimental Ophthalmology (2000) 28, 77–82
n^9 ?~ Original Article
E_:QSy5G Operated and unoperated cataract in Australia
u<Xog$esu Catherine A McCarty PhD, MPH, Mukesh B Nanjan PhD, Hugh R Taylor MD
W|UtY`1 Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
fE;Q:# Z. n Correspondence: Dr Cathy McCarty MPH, Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, 32 Gisborne Street, East Melbourne,
*|RS*ABte Victoria 3002, Australia. Email:
cathy@cera.unimelb.edu.au 3N4.$#>#9@ 78 McCarty et al.
+x1/-J8_sg Finally, four pairs of census collector districts in four rural
<y=ovkM3 Victorian communities were randomly selected to recruit rural
\"^%90F residents. A household census was conducted to identify
?J&)W,~ eligible residents aged 40 years and over who had been a
f&I7
,"v resident at that address for at least 6 months. At the time of
AU{:;%.g the household census, basic information about age, sex,
lOerrP6f( country of birth, language spoken at home, education, use of
uP|FJLY corrective spectacles and use of eye care services was collected.
j%tEZ"H Eligible residents were then invited to attend a local
S@}4-\ examination site for a more detailed interview and examination.
ycpE=fso' The study protocol was approved by the Royal Victorian
h)dRR_ Eye and Ear Hospital Human Research Ethics Committee.
Mg? L-C Assessment of cataract
2*OxA%QELM A standardized ophthalmic examination was performed after
5h^[^*A
? pupil dilatation with one drop of 10% phenylephrine
=ApY9` hydrochloride. Lens opacities were graded clinically at the
?q$P>guH6- time of the examination and subsequently from photos using
3%
vis\~^ the Wilmer cataract photo-grading system.12 Cortical and
]VjLKFb~U posterior subcapsular (PSC) opacities were assessed on
<GZhH: retroillumination and measured as the proportion (in 1/16)
jD9lz-Y@ of pupil circumference occupied by opacity. For this analysis,
{bkGYx5.C cortical cataract was defined as 4/16 or greater opacity,
)I9aC~eAD PSC cataract was defined as opacity equal to or greater than
DY3:#X`4 1 mm2 and nuclear cataract was defined as opacity equal to
Q[_Ni15 or greater than Wilmer standard 2,12 independent of visual
-c={+z " acuity. Examples of the minimum opacities defined as cortical,
]w22@s nuclear and PSC cataract are presented in Figure 1.
(%DRt4u<H Bilateral congenital cataracts or cataracts secondary to
4iBxPo(0 intraocular inflammation or trauma were excluded from the
z,+m[x=/N analysis. Two cases of bilateral secondary cataract and eight
!: |nI77| cases of bilateral congenital cataract were excluded from the
!-(J-45 analyses.
</Z
Ha:=7 A Topcon® SL5 photo slit-lamp (Topcon America Corp.,
.^H1\p];Lw Paramus, NJ, USA) with a 0.1 mm slit beam of 9.0 mm in
NG)7G
height set to an incident angle of 30° was used for examinations.
-\,VGudM} Ektachrome® 200 ASA colour slide film (Eastman
3"tg+DncC Kodak Company, Rochester, NY, USA) was used to photograph
SALCuo"L the nuclear opacities. The cortical opacities were
jt%
WPkY: photographed with an Oxford® retroillumination camera
bZ1 0v; (Marcher Enterprises Ltd, Hereford, UK) and T-MAX® 400
Ar5JP_M`E film (Eastman Kodak). Photographs were graded separately
C->[$HcRa by two research assistants and discrepancies were adjudicated
:BDviUC7Z by an independent reviewer. Any discrepancies
g&
>mP? between the clinical grades and the photograph grades were
h7RD`k:mF resolved. Except in cases where photographs were missing,
V
*uEJ6T the photograph grades were used in the analyses. Photograph
YiNo#M91 grades were available for 4301 (84%) for cortical
6#-Z@fz% cataract, 4147 (81%) for nuclear cataract and 4303 (84%)
ULrbQ}"cva for PSC cataract. Cataract status was classified according to
2w7@u/OC' the severity of the opacity in the worse eye.
U\;Ml Assessment of risk factors
:z124Zf A standardized questionnaire was used to obtain information
Oo$%Yh51~ about education, employment and ethnic background.11
N$*>suQ, Specific information was elicited on the occurrence, duration
6(sfpK' and treatment of a number of medical conditions,
l58l including ocular trauma, arthritis, diabetes, gout, hypertension
`|NevpXY1 and mental illness. Information about the use, dose and
a6 * Y%? duration of tobacco, alcohol, analgesics and steriods were
Qvs(Rt3?y collected, and a food frequency questionnaire was used to
=mAGD*NK
u determine current consumption of dietary sources of antioxidants
@Zh8 QI+ and use of vitamin supplements.
81cv:|" Data management and statistical analysis
eb(m8vLR Data were collected either by direct computer entry with a
739l%u }< questionnaire programmed in Paradox© (Carel Corporation,
<vO8_2,V- Ottawa, Canada) with internal consistency checks, or
RNl\`>Cz on self-coding forms. Open-ended responses were coded at
O]4W|WI3 a later time. Data that were entered on the self-coded forms
|)*m[_1 were entered into a computer with double data entry and
E)RI!0Ra reconciliation of any inconsistencies. Data range and consistency
hE9'F(87a checks were performed on the entire data set.
1h&)I%`? SAS© version 6.1 (SAS Institute, Cary, North Carolina) was
\qRjXadj employed for statistical analyses.
~7KynE Ninety-five per cent confidence limits around the agespecific
zd.1 rates were calculated according to Cochran13 to
Y^T-A}?` account for the effect of the cluster sampling. Ninety-five
X*43!\ per cent confidence limits around age-standardized rates
tOu90gu were calculated according to Breslow and Day.14 The strataspecific
U+I3 P data were weighted according to the 1996
mNGb}
lR Australian Bureau of Statistics census data15 to reflect the
1"*Nb5s cataract prevalence in the entire Victorian population.
}6yxt9 Univariate analyses with Student’s t-tests and chi-squared
oC^z_AtZ tests were first employed to evaluate risk factors for unoperated
ghE?8&@ iq cataract. Any factors with P < 0.10 were then fitted
}7f 1(#{7 into a backwards stepwise logistic regression model. For the
oaH+c9v Figure 1. Minimum levels of cortical (a), nuclear (b), and posterior subcapsular (c) cataract.
"E4i >g final multivariate models, P < 0.05 was considered statistically
9`hpa-m@ significant. Design effect was assessed through the use
dn:|m^<) of cluster-specific models and multivariate models. The
]l9,t5Y design effect was assumed to be additive and an adjustment
a3DoLq"/ made in the variance by adding the variance associated with
h$:&1jVY{ the design effect prior to constructing the 95% confidence
Q{(,/}kA- limits.
b{9HooQ{ RESULTS
Q_UCF'f;} Study population
61t- A total of 3271 (83%) of the Melbourne residents, 403
Hzk1LKsT# (90%) Melbourne nursing home residents, and 1473 (92%)
6c;?`C rural residents participated. In general, non-participants did
A[wxa not differ from participants.16 The study population was
&</@0 representative of the Victorian population and Australia as
U)T/.L{0i a whole.
@et3}-c The Melbourne residents ranged in age from 40 to
z}Mb4{d
1 98 years (mean = 59) and 1511 (46%) were male. The
4)c"@Zf Melbourne nursing home residents ranged in age from 46 to
)BM
WC
k 101 years (mean = 82) and 85 (21%) were men. The rural
1^Y:XJ73 residents ranged in age from 40 to 103 years (mean = 60)
b(.o|d /P and 701 (47.5%) were men.
~
33@H Prevalence of cataract and prior cataract surgery
RvgAI`T7$ As would be expected, the rate of any cataract increases
?>< dramatically with age (Table 1). The weighted rate of any
F".IB^}$ cataract in Victoria was 21.5% (95% CL 18.1, 24.9).
` wsMybe# Although the rates varied somewhat between the three
}lQn]q strata, they were not significantly different as the 95% confidence
~[bMfkc3 limits overlapped. The per cent of cataractous eyes
RQ$o'U9A with best-corrected visual acuity of less than 6/12 was 12.5%
rym\5
`) (65/520) for cortical cataract, 18% for nuclear cataract
/:c,v- (97/534) and 14.4% (27/187) for PSC cataract. Cataract
'yAoZ P\| surgery also rose dramatically with age. The overall
hdNZ":1s weighted rate of prior cataract surgery in Victoria was
~wd?-$;070 3.79% (95% CL 2.97, 4.60) (Table 2).
VIlQzM;%^ Risk factors for unoperated cataract
3dzqVaV Cases of cataract that had not been removed were classified
&@.=)4Y as unoperated cataract. Risk factor analyses for unoperated
nR|uAw cataract were not performed with the nursing home residents
HS7
G_ as information about risk factor exposure was not
"Qm~;x2kB available for this cohort. The following factors were assessed
5a/
A_..+I in relation to unoperated cataract: age, sex, residence
'\vmfp= (urban/rural), language spoken at home (a measure of ethnic
#I@[^^Vw integration), country of birth, parents’ country of birth (a
e+=G-u5}- measure of ethnicity), years since migration, education, use
!j\&BAxTEk of ophthalmic services, use of optometric services, private
H_nOE(i<z health insurance status, duration of distance glasses use,
J$=b&$I( glaucoma, age-related maculopathy and employment status.
n<(5B|~y In this cross sectional study it was not possible to assess the
U3R`mHr0 level of visual acuity that would predict a patient’s having
d'@H@ cataract surgery, as visual acuity data prior to cataract
Fl|&eO,e surgery were not available.
,Z\,IRn The significant risk factors for unoperated cataract in univariate
!z6/.>QJ~ analyses were related to: whether a participant had
t6>Qe ever seen an optometrist, seen an ophthalmologist or been
d4=u`2w diagnosed with glaucoma; and participants’ employment
5r}(|86O/ status (currently employed) and age. These significant
K#pt8Q factors were placed in a backwards stepwise logistic regression
#i#.tc model. The factors that remained significantly related
hI#M {cz to unoperated cataract were whether participants had ever
sf&K<C]( seen an ophthalmologist, seen an optometrist and been
x?&xz; diagnosed with glaucoma. None of the demographic factors
]R.Vq\A%S were associated with unoperated cataract in the multivariate
Tqh
Rs model.
g,]5&C T3v The per cent of participants with unoperated cataract
38S&7>0@|q who said that they were dissatisfied or very dissatisfied with
-2u+m Operated and unoperated cataract in Australia 79
42[:s: Table 1. Prevalence of any cataracta (excluding previous cataract surgery) by age, gender and cohort
745V!#3!M
Age group Sex Urban Rural Nursing home Weighted total
&
7nfTc (years) (%) (%) (%)
,]N%(>ot 40–49 Male 2.56 4.04 0.00 3.00 (1.91, 4.08)
G:s:NXy^ Female 2.61 1.70 0.00 2.36 (1.61, 3.10)
_BA_lkN+D 50–59 Male 7.69 6.94 0.00 7.47 (5.80, 9.15)
dWWkO03| Female 6.67 7.56 0.00 6.92 (5.60, 8.24)
=ZL}Av} 60–69 Male 20.7 25.0 10.0 22.0 (18.1, 26.0)
j`pR;XL1[ Female 27.9 35.7 37.5 30.3 (26.0, 34.7)
ee?ZkU#@ 70–79 Male 43.1 58.7 39.1 48.1 (41.2, 55.1)
+>%+r Female 58.6 66.2 55.6 61.0 (56.0, 65.9)
Lj AIB(* 80–89 Male 74.0 89.3 92.0 79.3 (72.3, 86.3)
rNO;yL4)ey Female 91.9 97.0 80.2 92.6 (86.4, 98.8)
UR=s{nFd 90 + Male 100.0 100.0 75.0 98.8 (96.2, 100.0)
51'SA
B09 Female 100.0 100.0 93.8 98.6 (97.0, 100.0)
Q]:%Jj2 Age-standardized
2^lT!X@ (95% CL) Combined 19.7 (16.3, 23.1) 23.2 (16.1, 30.2) 16.5 (2.06, 30.9) 21.5 (18.1, 25.0)
==r|]~x
aCortical > 4/16, nuclear > standard 2, posterior subcapsular > 1 mm2
#a
l^Uqd their current vision was 30% (290/683), compared with 27%
zQ_[wM- (26/95) of participants with prior cataract surgery (chisquared,
3k0%H]wt 1 d.f. = 0.25, P = 0.62).
/ kGX 6hh Outcomes of cataract surgery
G* 6<pp Two hundred and forty-nine eyes had undergone prior
8dB~09Z7 cataract surgery. Of these 249 operated eyes, 49 (20%) were
1uQf} left aphakic, 6 (2.4%) had anterior chamber intraocular
/RmCMT lenses and 194 (78%) had posterior chamber intraocular
aH"c0A lenses. The rate of capsulotomy in the eyes with intact
!r
<|F posterior capsules was 36% (73/202). Fifteen per cent of
_x{x#d;L3 eyes (17/114) with a clear posterior capsule had bestcorrected
8PS:yBkA| visual acuity of less than 6/12 compared with 43%
}O{"qs#) of eyes (6/14) with opaque capsules, and 15% of eyes
C^tC} n1D( (11/73) with prior capsulotomies (chi-squared, 2 d.f. = 7.21,
]~ M
-KT P = 0.027).
&Hxr3[+$ The percentage of eyes with best-corrected visual acuity
2ow\d b of 6/12 or better was 96% (302/314) for eyes without
Q1[s{, cataract, 88% (1417/1609) for eyes with prevalent cataract
uoHhp 4>^ and 85% (211/249) for eyes with operated cataract (chisquared,
es]m 6A 2 d.f. = 22.3), P < 0.001). Twenty-seven of the
+rY0/T_0, operated eyes (11%) had visual acuities of less than 6/18
7A-rF U$ (moderate vision impairment) (Fig. 2). A cause of this
t_Wn<)XA moderate visual impairment (but not the only cause) in four
uNg.y$>CX (15%) eyes was secondary to cataract surgery. Three of these
U8!njLC four eyes had undergone intracapsular cataract extraction
B)dynGF8i and the fourth eye had an opaque posterior capsule. No one
D
]eF3a.G had bilateral vision impairment as a result of their cataract
]0le=Ee^% surgery.
)Cl&"bX DISCUSSION
}D O# {@af To our knowledge, this is the first paper to systematically
ja2]VbB assess the prevalence of current cataract, previous cataract
|M_Bbo@ud surgery, predictors of unoperated cataract and the outcomes
9Ba<'wk/>" of cataract surgery in a population-based sample. The Visual
VJaL$Wv)H Impairment Project is unique in that the sampling frame and
K~>kruO"; high response rate have ensured that the study population is
5EUk
p6Y representative of Australians aged 40 years and over. Therefore,
)J0VB't these data can be used to plan age-related cataract
o_n.,=/cZ services throughout Australia.
?6bE!36 We found the rate of any cataract in those over the age
#p>PNW- of 40 years to be 22%. Although relatively high, this rate is
ceCshxTU significantly less than was reported in a number of previous
uJ$,e5q studies,2,4,6 with the exception of the Casteldaccia Eye
G`z
48 Study.5 However, it is difficult to compare rates of cataract
PhS"tOGtX between studies because of different methodologies and
{65X37W
cataract definitions employed in the various studies, as well
S}E@*t2h as the different age structures of the study populations.
r.GjM#X Other studies have used less conservative definitions of
c#DTL/8"DO cataract, thus leading to higher rates of cataract as defined.
1"k@O)?JP In most large epidemiologic studies of cataract, visual acuity
rSk $]E ]Z has not been included in the definition of cataract.
(ni$wjq=z^ Therefore, the prevalence of cataract may not reflect the
MqqS3
actual need for cataract surgery in the community.
'9)@ U+yfQ 80 McCarty et al.
L[K_!^MZ Table 2. Prevalence of previous cataract by age, gender and cohort
n7G$gLX Age group Gender Urban Rural Nursing home Weighted total
/d4xHt5a (years) (%) (%) (%)
w~9gZ&hdp 40–49 Male 1.14 0.00 0.00 0.80 (0.00, 1.81)
cg~FW2Q Female 0.00 0.00 0.00 0.00 (
vBp5&* 50–59 Male 0.68 0.58 0.00 0.65 (0.13, 1.17)
-|lnJg4 Female 0.57 0.00 0.00 0.41 (0.00, 1.00)
'K1w.hC< 60–69 Male 2.12 7.59 0.00 3.80 (1.41, 6.19)
4Zq5 Female 2.11 3.51 0.00 2.54 (1.81, 3.26)
:9
7`IV% 70–79 Male 8.22 9.85 8.70 8.75 (6.38, 11.1)
Qi%A/~ Female 7.21 7.86 7.02 7.41 (5.36, 9.46)
FueJe/~t 80–89 Male 25.0 30.0 14.3 26.2 (17.0, 35.4)
.UcS4JU Female 27.9 25.6 18.3 26.7 (20.2, 33.3)
(_T&2% 90 + Male 0.00 16.7 66.7 9.19 (0.00, 21.5)
/vhh2` Female 58.3 100.0 26.9 63.1 (44.4, 81.8)
)mEF_ & Age-standardized
-zkB`~u_ (95% CL) Combined 3.31 (2.70, 3.93) 4.36 (2.67, 6.06) 2.26 (0.82, 3.70) 3.79 (2.97, 4.60)
Nl+2m4 Figure 2. Visual acuity in eyes that had undergone cataract
g#AA.@/Z surgery, n = 249. h, Presenting; j, best-corrected.
(xTHin$ Operated and unoperated cataract in Australia 81
MS b{ve_ The weighted prevalence of prior cataract surgery in the
n)0{mDf% Visual Impairment Project (3.6%) was similar to the crude
y.nw6.`MR rate in the Beaver Dam Eye Study4 (3.1%), but less than the
y8L:nnSj crude rate in the Blue Mountains Eye Study6 (6.0%).
[B4?Z-K% However, the age-standardized rate in the Blue Mountains
82<L07fB Eye Study (standardized to the age distribution of the urban
CtfSfSAUuu Visual Impairment Project cohort) was found to be less than
Xy{b(b;9 the Visual Impairment Project (standardized rate = 1.36%,
=4I361oMf 95% CL 1.25, 1.47). The incidence of cataract surgery in
JB-j@ Australia has exceeded population growth.1 This is due,
~ce.
&C7cR perhaps, to advances in surgical techniques and lens
YmwVa
s implants that have changed the risk–benefit ratio.
}PXWRv.gW The Global Initiative for the Elimination of Avoidable
uODsXi{z Blindness, sponsored by the World Health Organization,
=nsY
[ s< states that cataract surgical services should be provided that
x6,RW],FGR ‘have a high success rate in terms of visual outcome and
YMWy5 \ improved quality of life’,17 although the ‘high success rate’ is
IP >An8+ not defined. Population- and clinic-based studies conducted
Rl(b tr1w in the United States have demonstrated marked improvement
}bHpFe in visual acuity following cataract surgery.18–20 We
8(A:XQN"h found that 85% of eyes that had undergone cataract extraction
R%Z} J R. had visual acuity of 6/12 or better. Previously, we have
kA3kh`l shown that participants with prevalent cataract in this
s:_5p`w> cohort are more likely to express dissatisfaction with their
K'tz_:d| current vision than participants without cataract or participants
A@#dv2JzP with prior cataract surgery.21 In a national study in the
b,'./{c0 United States, researchers found that the change in patients’
xs:{%ki ratings of their vision difficulties and satisfaction with their
mZ5UaSG vision after cataract surgery were more highly related to
R|vF*0)>W their change in visual functioning score than to their change
dlU=k9N- in visual acuity.19 Furthermore, improvement in visual function
Vlf@T has been shown to be associated with improvement in
:Cuae?O, overall quality of life.22
XyI w5
9 A recent review found that the incidence of visually
Ia\Nj
_-%L significant posterior capsule opacification following
MqpoS cataract surgery to be greater than 25%.23 We found 36%
yTEuf@ capsulotomy in our population and that this was associated
DXiD>1(q with visual acuity similar to that of eyes with a clear
&a:aW;^A7 capsule, but significantly better than that of eyes with an
;~K($_#H opaque capsule.
@
!S$gTz A number of studies have shown that the demand and
w.3R1}R timing of cataract surgery vary according to visual acuity,
&yN<@. degree of handicap and socioeconomic factors.8–10,24,25 We
#i,O
"`4 have also shown previously that ophthalmologists are more
^\I$tnY` likely to refer a patient for cataract surgery if the patient is
KYQ6U.%W employed and less likely to refer a nursing home resident.7
aJF`
rLm In the Visual Impairment Project, we did not find that any
1Y`MJ\9 particular subgroup of the population was at greater risk of
9D<HJ( having unoperated cataract. Universal access to health care
. FruI#99 in Australia may explain the fact that people without
qL#R
XUTP Medicare are more likely to delay cataract operations in the
ieI-_]|[ USA,8 but not having private health insurance is not associated
l\5NuCgRY with unoperated cataract in Australia.
U}7[8&k1 In summary, cataract is a significant public health problem
<ZiO[dEV in that one in four people in their 80s will have had cataract
%Xl@o surgery. The importance of age-related cataract surgery will
\5Jv;gc\\ increase further with the ageing of the population: the
v\Hyu1;8 number of people over age 60 years is expected to double in
_e'mG'P( the next 20 years. Cataract surgery services are well
L:<'TXsRA accessed by the Victorian population and the visual outcomes
W@tLT[}CG of cataract surgery have been shown to be very good.
N_<n$3P\?f These data can be used to plan for age-related cataract
|2# Ro* surgical services in Australia in the future as the need for
N9Ml&*%oX{ cataract extractions increases.
#q- _
ACKNOWLEDGEMENTS
R<=t{vTJ5 The Visual Impairment Project was funded in part by grants
pr"flRQr# from the Victorian Health Promotion Foundation, the
`g=~u{0 National Health and Medical Research Council, the Ansell
=N
c`hP Ophthalmology Foundation, the Dorothy Edols Estate and
X&IY(CX the Jack Brockhoff Foundation. Dr McCarty is the recipient
D\R^*k@V of a Wagstaff Fellowship in Ophthalmology from the Royal
zvD5i,I Victorian Eye and Ear Hospital.
7h2bL6Y88 REFERENCES
S\A[Z&k0
1. Keeffe JE, Taylor HR. Cataract surgery in Australia 1985–94.
O^#u%/ Aust. N.Z. J. Ophthalmol. 1996; 24: 313–17.
[7V]=] p 2. Sperduto RD, Hiller R. The prevalence of nuclear, cortical,
Ei-OuDM;) and posterior subcapsular lens opacities in a general population
7 SZR#L sample. Ophthalmology 1984; 91: 815–18.
]_?y[@ZP 3. Maraini G, Pasquini P, Sperduto RD et al. Distribution of lens
Xhi?b
| opacities in the Italian-American case–control study of agerelated
R.N*G]K5 cataract. Ophthalmology 1990; 97: 752–6.
;[9Is\ 4. Klein BEK, Klein R, Linton KLP. Prevalence of age-related
9:o3JGHSc lens opacities in a population. The Beaver Dam Eye Study.
Xdt+\}\ Ophthalmology 1992; 99: 546–52.
rRYf.~UH@P 5. Guiffrè G, Giammanco R, Di Pace F, Ponte F. Casteldaccia eye
_3a
5/IZ study: prevalence of cataract in the adult and elderly population
<.ky1aex7 of a Mediterranean town. Int. Ophthalmol. 1995; 18:
^~l<N@ 363–71.
4)I#[&f 6. Mitchell P, Cumming RG, Attebo K, Panchapakesan J.
'QF
>e Prevalence of cataract in Australia. The Blue Mountains Eye
W<"\hQI Study. Ophthalmology 1997; 104: 581–8.
5eA]7$ic 7. Keeffe JE, McCarty CA, Chang WP, Steinberg EP, Taylor HR.
m{c#cR Relative importance of VA, patient concern and patient
K8Zk{on lifestyle on referral for cataract surgery. Invest. Ophthalmol. Vis.
lvi:I+VgA Sci. 1996; 37: S183.
Z"X*FzFo 8. Curbow B, Legro MW, Brenner MH. The influence of patientrelated
$:!T/*p* variables in the timing of cataract extraction. Am. J.
^ {f^WL= Ophthalmol. 1993; 115: 614–22.
\DK*>
k 9. Sletteberg OH, Høvding G, Bertelsen T. Do we operate too
C&kl*nO many cataracts? The referred cataract patients’ own appraisal
!`o:+Gg@ of their need for surgery. Acta Ophthalmol. Scand. 1995; 73:
~-wJ#E3g 77–80.
/}_c7+// 10. Escarce JJ. Would eliminating differences in physician practice
XWpnZFjE style reduce geographic variations in cataract surgery rates?
Tj5@OcA$ Med. Care 1993; 31: 1106–18.
n5*7~K"C 11. Livingston PM, Carson CA, Stanislavsky YL, Lee SE, Guest
yX3H&F6 CS, Taylor HR. Methods for a population-based study of eye
Eu.qA9,@U disease: the Melbourne Visual Impairment Project. Ophthalmic
k^c=y<I Epidemiol. 1994; 1: 139–48.
K/v-P <g 12. Taylor HR, West SK. A simple system for the clinical grading
Mk/!,N<h# of lens opacities. Lens Res. 1988; 5: 175–81.
oh0|2IrM 82 McCarty et al.
eZ5}O
0sfp 13. Cochran WG. Sampling Techniques. New York: John Wiley &
#UC
QiQfP Sons, 1977; 249–73.
Gj8[*3d 14. Breslow NE, Day NE. Statistical Methods in Cancer Research. Volume
#aY<J:Nx II – the Design and Analysis of Cohort Studies. Lyon: International
~Z6p3#
!o Agency for Research on Cancer; 1987; 52–61.
U4
l*;od 15. Australian Bureau of Statistics. 1996 Census of Population and
wx%nTf/Oa Housing. Canberra: Australian Bureau of Statistics, 1997.
a {$k<@Ww 16. Livingston PM, Lee SE, McCarty CA, Taylor HR. A comparison
>ydb? of participants with non-participants in a populationbased
J:Y|O-S! epidemiologic study: the Melbourne Visual Impairment
|4> r" Project. Ophthalmic Epidemiol. 1997; 4: 73–82.
9'#.>Q>0=j 17. Programme for the Prevention of Blindness. Global Initiative for the
Am%a4{b Elimination of Avoidable Blindness. Geneva: World Health
|+xtFe Organization, 1997.
dwbY"t[9 18. Applegate WB, Miller ST, Elam JT, Freeman JM, Wood TO,
ph12x: @B Gettlefinger TC. Impact of cataract surgery with lens implantation
Jv^cOc on vision and physical function in elderly patients.
_O)2 JAMA 1987; 257: 1064–6.
j)tCr Py 19. Steinberg EP, Tielsch JM, Schein OD et al. National Study of
vgA!?P3 Cataract Surgery Outcomes. Variation in 4-month postoperative
%f_OP$;fc outcomes as reflected in multiple outcome measures.
]AZ\5C-J Ophthalmology 1994; 101:1131–41.
k CW!m 20. Klein BEK, Klein R, Moss SE. Change in visual acuity associated
lc3
S|4 with cataract surgery. The Beaver Dam Eye Study.
O`[iz/7m Ophthalmology 1996; 103: 1727–31.
Pm#x?1rAj 21. McCarty CA, Keeffe JE, Taylor HR. The need for cataract
%V <F< surgery: projections based on lens opacity, visual acuity, and
^0x.'G? personal concern. Br. J. Ophthalmol. 1999; 83: 62–5.
q?Ku}eID3 22. Brenner MH, Curbow B, Javitt JC, Legro MW, Sommer A.
le^_6|ek Vision change and quality of life in the elderly. Response to
ua$k^m7m5 cataract surgery and treatment of other ocular conditions.
tf7v5iG e Arch. Ophthalmol. 1993; 111: 680–5.
6}i&6@Snq? 23. Schaumberg DA, Dana MR, Christen WG, Glynn RJ. A
KI Plb3oh systematic overview of the incidence of posterior capsule
UR/qVO? opacification. Ophthalmology 1998; 105: 1213–21.
jV4hxuc$ 24. Mordue A, Parkin DW, Baxter C, Fawcett G, Stewart M.
RQo$iISwy Thresholds for treatment in cataract surgery. J. Public Health
yxG:\y
b Med. 1994; 16: 393–8.
QxL@'n#5 25. Norregaard JC, Bernth-Peterson P, Alonso J et al. Variations in
VA=#0w indications for cataract surgery in the United States, Denmark,
M$&WM{Pr^ Canada, and Spain: results from the International Cataract
)RA\kZ " Surgery Outcomes Study. Br. J. Ophthalmol. 1998; 82: 1107–11.