ABSTRACT
Kmv+1T0, Purpose: To quantify the prevalence of cataract, the outcomes
ld7v3:M of cataract surgery and the factors related to
!\;FNu8_. unoperated cataract in Australia.
aCxE5$~$ Methods: Participants were recruited from the Visual
NwR}yb6 Impairment Project: a cluster, stratified sample of more than
eDZ8w 5000 Victorians aged 40 years and over. At examination
2kUxD8BcN sites interviews, clinical examinations and lens photography
A
&9(mB were performed. Cataract was defined in participants who
T!}[yW had: had previous cataract surgery, cortical cataract greater
cFF*Z=L_ than 4/16, nuclear greater than Wilmer standard 2, or
[
dE.
[ posterior subcapsular greater than 1 mm2.
'iY*6<xS< Results: The participant group comprised 3271 Melbourne
e~T@~(fft residents, 403 Melbourne nursing home residents and 1473
nPgeLG"00 rural residents.The weighted rate of any cataract in Victoria
<(e8sNe was 21.5%. The overall weighted rate of prior cataract
:ECi+DxBK surgery was 3.79%. Two hundred and forty-nine eyes had
=_8Tp~j had prior cataract surgery. Of these 249 procedures, 49
io3yLIy, (20%) were aphakic, 6 (2.4%) had anterior chamber
X}6#II intraocular lenses and 194 (78%) had posterior chamber
Sj(F3wY intraocular lenses.Two hundred and eleven of these operated
oQj=;[ eyes (85%) had best-corrected visual acuity of 6/12 or
^-M^gYBR better, the legal requirement for a driver’s license.Twentyseven
ag4`n:1 (11%) had visual acuity of less than 6/18 (moderate
Pu>N_^ C vision impairment). Complications of cataract surgery
1Ee>S\9t caused reduced vision in four of the 27 eyes (15%), or 1.9%
i
NWC6y of operated eyes. Three of these four eyes had undergone
]> Y/r-! intracapsular cataract extraction and the fourth eye had an
#m8sK(#lo opaque posterior capsule. No one had bilateral vision
r++i=SQax impairment as a result of cataract surgery. Surprisingly, no
)J3kxmlzQ particular demographic factors (such as age, gender, rural
#rYENR[ residence, occupation, employment status, health insurance
p11G#.0 status, ethnicity) were related to the presence of unoperated
(w2=
2$ cataract.
w9#R' Conclusions: Although the overall prevalence of cataract is
^i:\@VA: quite high, no particular subgroup is systematically underserviced
C/v}^#cLD in terms of cataract surgery. Overall, the results of
Z]-WFU_
N cataract surgery are very good, with the majority of eyes
Dr"/3xm achieving driving vision following cataract extraction.
?|t/mo|K? Key words: cataract extraction, health planning, health
}&G]0hCT! services accessibility, prevalence
+CTmcbyOi INTRODUCTION
Ud3""C5B Cataract is the leading cause of blindness worldwide and, in
j.QHkI1. Australia, cataract extractions account for the majority of all
Qm);6X
ophthalmic procedures.1 Over the period 1985–94, the rate
nN ~GP"} of cataract surgery in Australia was twice as high as would be
O2H/rFx4 expected from the growth in the elderly population.1
c d%hW Although there have been a number of studies reporting
x9}++r the prevalence of cataract in various populations,2–6 there is
s[-]cHQ little information about determinants of cataract surgery in
vbn>
mg5 the population. A previous survey of Australian ophthalmologists
`Ei"_W showed that patient concern and lifestyle, rather
La}o(7=s than visual acuity itself, are the primary factors for referral
Wg1
tip8s for cataract surgery.7 This supports prior research which has
%\yK5V5 shown that visual acuity is not a strong predictor of need for
B+D`\ Nl o cataract surgery.8,9 Elsewhere, socioeconomic status has
h[l{ 5Z* been shown to be related to cataract surgery rates.10
~_}4jnC To appropriately plan health care services, information is
&PWf:y{R` needed about the prevalence of age-related cataract in the
fm6]CU1^ community as well as the factors associated with cataract
fMB4xbpD surgery. The purpose of this study is to quantify the prevalence
?zE< of any cataract in Australia, to describe the factors
R`7n^, related to unoperated cataract in the community and to
X)NWX9^;' describe the visual outcomes of cataract surgery.
<tQXK; METHODS
(lb`#TTG
x Study population
ZE ^u .>5 Details about the study methodology for the Visual
'Ix5,^M}B Impairment Project have been published previously.11
K*[0dza$ Briefly, cluster sampling within three strata was employed to
KPg[-
d recruit subjects aged 40 years and over to participate.
@d
P~X Within the Melbourne Statistical Division, nine pairs of
DlS&qFs census collector districts were randomly selected. Fourteen
(mY(\mu} nursing homes within a 5 km radius of these nine test sites
C*]AL/ were randomly chosen to recruit nursing home residents.
_dY:)%[] Clinical and Experimental Ophthalmology (2000) 28, 77–82
v6KL93 Original Article
i~ROQMN1 Operated and unoperated cataract in Australia
_i.({s&_9 Catherine A McCarty PhD, MPH, Mukesh B Nanjan PhD, Hugh R Taylor MD
_4~k3%w\`l Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
"{mt? n Correspondence: Dr Cathy McCarty MPH, Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, 32 Gisborne Street, East Melbourne,
%pd5w~VP Victoria 3002, Australia. Email:
cathy@cera.unimelb.edu.au IZ|c<#r6 78 McCarty et al.
rkbl/py Finally, four pairs of census collector districts in four rural
IBzHR[#,^ Victorian communities were randomly selected to recruit rural
uFMs^^# residents. A household census was conducted to identify
rK*hTjVn eligible residents aged 40 years and over who had been a
nz}]C04:- resident at that address for at least 6 months. At the time of
sn2r>m3 the household census, basic information about age, sex,
DI L)7K4 country of birth, language spoken at home, education, use of
;CLR{t(N#V corrective spectacles and use of eye care services was collected.
|Tj`qJGVw Eligible residents were then invited to attend a local
2#,8evH examination site for a more detailed interview and examination.
~:R4))qpg The study protocol was approved by the Royal Victorian
Oz_b3r Eye and Ear Hospital Human Research Ethics Committee.
Xcs8zT Assessment of cataract
PEMxoe<+ A standardized ophthalmic examination was performed after
6nM
rO$i0k pupil dilatation with one drop of 10% phenylephrine
H&"_} hydrochloride. Lens opacities were graded clinically at the
$Ui]hA-:?y time of the examination and subsequently from photos using
54, Ju'r the Wilmer cataract photo-grading system.12 Cortical and
"j*fVn posterior subcapsular (PSC) opacities were assessed on
Z&2
&wD retroillumination and measured as the proportion (in 1/16)
;,[EJR^CI of pupil circumference occupied by opacity. For this analysis,
+_vm\]4 cortical cataract was defined as 4/16 or greater opacity,
J
tn&o"C PSC cataract was defined as opacity equal to or greater than
rd f85%%7 1 mm2 and nuclear cataract was defined as opacity equal to
*<#]&2I or greater than Wilmer standard 2,12 independent of visual
d#M?lS> acuity. Examples of the minimum opacities defined as cortical,
uWM4O@Qn)d nuclear and PSC cataract are presented in Figure 1.
?CL
z@u~ Bilateral congenital cataracts or cataracts secondary to
F~11 _ intraocular inflammation or trauma were excluded from the
(RI>aDGRH analysis. Two cases of bilateral secondary cataract and eight
@Reh?]# v cases of bilateral congenital cataract were excluded from the
d-_93 analyses.
-&HoR!af A Topcon® SL5 photo slit-lamp (Topcon America Corp.,
g
tSHy*3] Paramus, NJ, USA) with a 0.1 mm slit beam of 9.0 mm in
(\AszLW height set to an incident angle of 30° was used for examinations.
f/|a?n2\hm Ektachrome® 200 ASA colour slide film (Eastman
rkER` Kodak Company, Rochester, NY, USA) was used to photograph
^{:[^$f:l the nuclear opacities. The cortical opacities were
,YzC)(- photographed with an Oxford® retroillumination camera
^AC+nko* (Marcher Enterprises Ltd, Hereford, UK) and T-MAX® 400
{ U2|): film (Eastman Kodak). Photographs were graded separately
q@=#`74 6e by two research assistants and discrepancies were adjudicated
yO69p by an independent reviewer. Any discrepancies
TBLk+AR between the clinical grades and the photograph grades were
62KW
HB9S resolved. Except in cases where photographs were missing,
Ij,?G* the photograph grades were used in the analyses. Photograph
u8)r
W grades were available for 4301 (84%) for cortical
6!Ap;O^* cataract, 4147 (81%) for nuclear cataract and 4303 (84%)
$DMu~wwfG for PSC cataract. Cataract status was classified according to
RM=+ZmA the severity of the opacity in the worse eye.
W,eKQV<j Assessment of risk factors
-
G2M;]Cn A standardized questionnaire was used to obtain information
{b8 Y- about education, employment and ethnic background.11
FWx*&y~$ Specific information was elicited on the occurrence, duration
b`%e{99\ and treatment of a number of medical conditions,
4Fht(B| including ocular trauma, arthritis, diabetes, gout, hypertension
g
0_r and mental illness. Information about the use, dose and
'/)_{Ly duration of tobacco, alcohol, analgesics and steriods were
sA7K ;J}) collected, and a food frequency questionnaire was used to
[T&y5"@
determine current consumption of dietary sources of antioxidants
/bj`%Q.n and use of vitamin supplements.
rsj}hS$ Data management and statistical analysis
i!-sbwd7 Data were collected either by direct computer entry with a
?26[%% questionnaire programmed in Paradox© (Carel Corporation,
G
U/k^Qy Ottawa, Canada) with internal consistency checks, or
#6Ph"\G/ on self-coding forms. Open-ended responses were coded at
.VV!$;
FB a later time. Data that were entered on the self-coded forms
\O4=mJ were entered into a computer with double data entry and
K#yH\fn8 reconciliation of any inconsistencies. Data range and consistency
~x\Q\Cxp checks were performed on the entire data set.
mT$tAwzTC{ SAS© version 6.1 (SAS Institute, Cary, North Carolina) was
[vT,zM
employed for statistical analyses.
7!r`DZ"yF Ninety-five per cent confidence limits around the agespecific
r+yLK(<zp rates were calculated according to Cochran13 to
d'J?QH!N0 account for the effect of the cluster sampling. Ninety-five
T8
oASg! per cent confidence limits around age-standardized rates
Nd)o1{I were calculated according to Breslow and Day.14 The strataspecific
t;6/bT- data were weighted according to the 1996
0`=?ig
_ Australian Bureau of Statistics census data15 to reflect the
6lFs N2 cataract prevalence in the entire Victorian population.
[K QZHIe Univariate analyses with Student’s t-tests and chi-squared
a}{! %5 tests were first employed to evaluate risk factors for unoperated
]d(}b>gR~( cataract. Any factors with P < 0.10 were then fitted
*a@UV%u into a backwards stepwise logistic regression model. For the
q>Y[.c- Figure 1. Minimum levels of cortical (a), nuclear (b), and posterior subcapsular (c) cataract.
ShxX[k final multivariate models, P < 0.05 was considered statistically
,
iy significant. Design effect was assessed through the use
b@Cvs4 of cluster-specific models and multivariate models. The
aT[7L9Cw design effect was assumed to be additive and an adjustment
Rl8-a8j$f. made in the variance by adding the variance associated with
F*H}5yBp_: the design effect prior to constructing the 95% confidence
-t?G8,, limits.
#U6qM(J RESULTS
}% *g\%L Study population
+f+yh0Dj A total of 3271 (83%) of the Melbourne residents, 403
/|f]L9)2< (90%) Melbourne nursing home residents, and 1473 (92%)
B*7o\~5 rural residents participated. In general, non-participants did
8!fwXm not differ from participants.16 The study population was
=G :H)i representative of the Victorian population and Australia as
P8f-&( a whole.
511q\w M The Melbourne residents ranged in age from 40 to
lVHJ}(<'p 98 years (mean = 59) and 1511 (46%) were male. The
2_C
.-;! Melbourne nursing home residents ranged in age from 46 to
*k -UQLJ 101 years (mean = 82) and 85 (21%) were men. The rural
5l#)tX.by residents ranged in age from 40 to 103 years (mean = 60)
1A`u0Y$g and 701 (47.5%) were men.
@B6[RZ R Prevalence of cataract and prior cataract surgery
v*pVcBY> As would be expected, the rate of any cataract increases
AyUVsIuPT= dramatically with age (Table 1). The weighted rate of any
p5\b&~
g cataract in Victoria was 21.5% (95% CL 18.1, 24.9).
JT+P>\\];' Although the rates varied somewhat between the three
G(>a LF strata, they were not significantly different as the 95% confidence
_F9
c.BH limits overlapped. The per cent of cataractous eyes
ZyG528O22 with best-corrected visual acuity of less than 6/12 was 12.5%
qlu yJpt (65/520) for cortical cataract, 18% for nuclear cataract
g?ft;kR6S (97/534) and 14.4% (27/187) for PSC cataract. Cataract
I/adzLQ surgery also rose dramatically with age. The overall
No?pv" weighted rate of prior cataract surgery in Victoria was
L(L;z'3y 3.79% (95% CL 2.97, 4.60) (Table 2).
]du pU"VV Risk factors for unoperated cataract
WE3l*7<@ Cases of cataract that had not been removed were classified
s<myZ T$ as unoperated cataract. Risk factor analyses for unoperated
g)zy^aDf cataract were not performed with the nursing home residents
MxY CMe4S[ as information about risk factor exposure was not
^vzNs>eJ available for this cohort. The following factors were assessed
9T\:ID=h in relation to unoperated cataract: age, sex, residence
\ZA%"F){ (urban/rural), language spoken at home (a measure of ethnic
qYE -z(i integration), country of birth, parents’ country of birth (a
>q`G?9d2 measure of ethnicity), years since migration, education, use
A&z of ophthalmic services, use of optometric services, private
TOQvZ?_ health insurance status, duration of distance glasses use,
b747 eR 7E glaucoma, age-related maculopathy and employment status.
"kMpa]<c-6 In this cross sectional study it was not possible to assess the
sYvO"| level of visual acuity that would predict a patient’s having
ztf (.~ cataract surgery, as visual acuity data prior to cataract
&cZD{Z surgery were not available.
xD1w#FMlQs The significant risk factors for unoperated cataract in univariate
S
wQb" analyses were related to: whether a participant had
srUpG&Bcx
ever seen an optometrist, seen an ophthalmologist or been
^58'*13ZL diagnosed with glaucoma; and participants’ employment
.a$][Jny status (currently employed) and age. These significant
TzVNZDQ`Jl factors were placed in a backwards stepwise logistic regression
k)'c$ model. The factors that remained significantly related
2OEOb,` to unoperated cataract were whether participants had ever
RzXxnx)]q seen an ophthalmologist, seen an optometrist and been
y!!p:3 diagnosed with glaucoma. None of the demographic factors
[&6l=a were associated with unoperated cataract in the multivariate
Z|E( !"zE9 model.
H+F'K
XP*K The per cent of participants with unoperated cataract
a(!:a+9WOP who said that they were dissatisfied or very dissatisfied with
t[%9z6t Operated and unoperated cataract in Australia 79
R|Y)ow51 Table 1. Prevalence of any cataracta (excluding previous cataract surgery) by age, gender and cohort
\3Ys8umKq Age group Sex Urban Rural Nursing home Weighted total
tvZpm@1 (years) (%) (%) (%)
^2XoYgv 40–49 Male 2.56 4.04 0.00 3.00 (1.91, 4.08)
"C%;9_ig$ Female 2.61 1.70 0.00 2.36 (1.61, 3.10)
TAIcp*)ZM 50–59 Male 7.69 6.94 0.00 7.47 (5.80, 9.15)
~%m-}Sxc Female 6.67 7.56 0.00 6.92 (5.60, 8.24)
1P@&xcvS\ 60–69 Male 20.7 25.0 10.0 22.0 (18.1, 26.0)
g.Z>9(>;Y Female 27.9 35.7 37.5 30.3 (26.0, 34.7)
"EDn;l-Q 70–79 Male 43.1 58.7 39.1 48.1 (41.2, 55.1)
aa8WRf Female 58.6 66.2 55.6 61.0 (56.0, 65.9)
26&^n
Uy 80–89 Male 74.0 89.3 92.0 79.3 (72.3, 86.3)
Xq
1n1_Z Female 91.9 97.0 80.2 92.6 (86.4, 98.8)
[-=PK\ B 90 + Male 100.0 100.0 75.0 98.8 (96.2, 100.0)
48Z{wV, Female 100.0 100.0 93.8 98.6 (97.0, 100.0)
%HpTQ Age-standardized
<{JHFU`^ (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)
Gmf.lHr$% aCortical > 4/16, nuclear > standard 2, posterior subcapsular > 1 mm2
0,{Dw9
W: their current vision was 30% (290/683), compared with 27%
]+{Cy\*kR (26/95) of participants with prior cataract surgery (chisquared,
X)$3sTj 1 d.f. = 0.25, P = 0.62).
EL;Ir tU Outcomes of cataract surgery
mpIRe@#Z Two hundred and forty-nine eyes had undergone prior
A\CtM` cataract surgery. Of these 249 operated eyes, 49 (20%) were
e%afK@c left aphakic, 6 (2.4%) had anterior chamber intraocular
=hH>]$J[ lenses and 194 (78%) had posterior chamber intraocular
lc,{0$
1< lenses. The rate of capsulotomy in the eyes with intact
b54<1\& posterior capsules was 36% (73/202). Fifteen per cent of
{Nuwz|Ci eyes (17/114) with a clear posterior capsule had bestcorrected
No=Ig-It
visual acuity of less than 6/12 compared with 43%
s7A{<>: of eyes (6/14) with opaque capsules, and 15% of eyes
|<96H8 (11/73) with prior capsulotomies (chi-squared, 2 d.f. = 7.21,
5wmH3g#0 P = 0.027).
1Thr74M The percentage of eyes with best-corrected visual acuity
s/Fc7V!; of 6/12 or better was 96% (302/314) for eyes without
Oz#$
x cataract, 88% (1417/1609) for eyes with prevalent cataract
fIu5d6;' and 85% (211/249) for eyes with operated cataract (chisquared,
"WdGY*r 2 d.f. = 22.3), P < 0.001). Twenty-seven of the
R
rs?I,NV operated eyes (11%) had visual acuities of less than 6/18
2
:u4~E3 (moderate vision impairment) (Fig. 2). A cause of this
#oSQWC=T moderate visual impairment (but not the only cause) in four
BC ]^BKP (15%) eyes was secondary to cataract surgery. Three of these
*91iFeKj= four eyes had undergone intracapsular cataract extraction
0}2Uj>!i and the fourth eye had an opaque posterior capsule. No one
_iLXs had bilateral vision impairment as a result of their cataract
Z$ Fh4 surgery.
w|pk1~c(_ DISCUSSION
<"{Lv)4 To our knowledge, this is the first paper to systematically
5V!L~# assess the prevalence of current cataract, previous cataract
}jBr[S5 surgery, predictors of unoperated cataract and the outcomes
;n$j?n+| of cataract surgery in a population-based sample. The Visual
3Q*K+(`{ Impairment Project is unique in that the sampling frame and
gRIRc4p high response rate have ensured that the study population is
\~UyfVPRT representative of Australians aged 40 years and over. Therefore,
d|k6#f-E these data can be used to plan age-related cataract
ny%-u&1k services throughout Australia.
e;~[PYeu We found the rate of any cataract in those over the age
7r 07N' of 40 years to be 22%. Although relatively high, this rate is
QFU;\H/ significantly less than was reported in a number of previous
3C 84b/A studies,2,4,6 with the exception of the Casteldaccia Eye
v^2K=f[nE Study.5 However, it is difficult to compare rates of cataract
&1YAPxX between studies because of different methodologies and
Y,I0o{,g cataract definitions employed in the various studies, as well
jG)fM? as the different age structures of the study populations.
| V Ps5 Other studies have used less conservative definitions of
P0uUVU=B| cataract, thus leading to higher rates of cataract as defined.
" NnUu8x In most large epidemiologic studies of cataract, visual acuity
GV#"2{t
j has not been included in the definition of cataract.
+Rn]6}5m\ Therefore, the prevalence of cataract may not reflect the
9iGUE actual need for cataract surgery in the community.
gfG Mu0FjB 80 McCarty et al.
Z
y _A3m{ Table 2. Prevalence of previous cataract by age, gender and cohort
DcaVT]" Age group Gender Urban Rural Nursing home Weighted total
.vYU4g] (years) (%) (%) (%)
\L}aTCvG 40–49 Male 1.14 0.00 0.00 0.80 (0.00, 1.81)
P,lKa. Female 0.00 0.00 0.00 0.00 (
lgFA}p@ 50–59 Male 0.68 0.58 0.00 0.65 (0.13, 1.17)
.)~IoIW= Female 0.57 0.00 0.00 0.41 (0.00, 1.00)
I!3qb-.Q 60–69 Male 2.12 7.59 0.00 3.80 (1.41, 6.19)
VCfa<hn Female 2.11 3.51 0.00 2.54 (1.81, 3.26)
kaf4GME] 70–79 Male 8.22 9.85 8.70 8.75 (6.38, 11.1)
!PJD+SrG Female 7.21 7.86 7.02 7.41 (5.36, 9.46)
_]:wltPv 80–89 Male 25.0 30.0 14.3 26.2 (17.0, 35.4)
Tl"GOpH\] Female 27.9 25.6 18.3 26.7 (20.2, 33.3)
s"*ZQ0OaD 90 + Male 0.00 16.7 66.7 9.19 (0.00, 21.5)
]pr( hk Female 58.3 100.0 26.9 63.1 (44.4, 81.8)
Jk=E"I6 Age-standardized
~ /s(.oji (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)
s<,[xkMB Figure 2. Visual acuity in eyes that had undergone cataract
0Snl_@s surgery, n = 249. h, Presenting; j, best-corrected.
pv)
;LjF Operated and unoperated cataract in Australia 81
# rnO=N8 The weighted prevalence of prior cataract surgery in the
?IgM=@ Visual Impairment Project (3.6%) was similar to the crude
8U}BSM_<2 rate in the Beaver Dam Eye Study4 (3.1%), but less than the
+Y;/10p crude rate in the Blue Mountains Eye Study6 (6.0%).
/J{
e_a However, the age-standardized rate in the Blue Mountains
n<RvL^T=
Eye Study (standardized to the age distribution of the urban
$OEhdz&Fi Visual Impairment Project cohort) was found to be less than
esE5#Yq4.k the Visual Impairment Project (standardized rate = 1.36%,
BPRhGG|9j 95% CL 1.25, 1.47). The incidence of cataract surgery in
.3Ex=aQcX Australia has exceeded population growth.1 This is due,
eru2.(1 perhaps, to advances in surgical techniques and lens
{[B^~Y>Lr implants that have changed the risk–benefit ratio.
)Pr*\<Cld The Global Initiative for the Elimination of Avoidable
um.s:vj$ Blindness, sponsored by the World Health Organization,
w]2tb states that cataract surgical services should be provided that
Py?EA*(d# ‘have a high success rate in terms of visual outcome and
}?PvNK]", improved quality of life’,17 although the ‘high success rate’ is
F"2rX&W not defined. Population- and clinic-based studies conducted
H# P)n
R
M in the United States have demonstrated marked improvement
x.gRTR`7( in visual acuity following cataract surgery.18–20 We
r7dvj#^ found that 85% of eyes that had undergone cataract extraction
c:;m BS>~ had visual acuity of 6/12 or better. Previously, we have
aX`@WXK shown that participants with prevalent cataract in this
/m>%=_nz cohort are more likely to express dissatisfaction with their
^uG^XY&ItC current vision than participants without cataract or participants
3RYg-$NK[ with prior cataract surgery.21 In a national study in the
ZAKNyA2 United States, researchers found that the change in patients’
Y@
&1[Z ratings of their vision difficulties and satisfaction with their
/Q |guJx vision after cataract surgery were more highly related to
N\Nw mx their change in visual functioning score than to their change
'a&( r; in visual acuity.19 Furthermore, improvement in visual function
WziX1%0$n has been shown to be associated with improvement in
-;VKtBXP</ overall quality of life.22
S`N_}, A recent review found that the incidence of visually
?/EyfTex significant posterior capsule opacification following
Y(:.f-Du cataract surgery to be greater than 25%.23 We found 36%
/CXrxeo capsulotomy in our population and that this was associated
/Ah|Po with visual acuity similar to that of eyes with a clear
=CCxY7)M+. capsule, but significantly better than that of eyes with an
Dg:2*m_!j{ opaque capsule.
{e>E4
( A number of studies have shown that the demand and
GpW5)a timing of cataract surgery vary according to visual acuity,
oH[4<K> degree of handicap and socioeconomic factors.8–10,24,25 We
ao@"j}c have also shown previously that ophthalmologists are more
'[XtARtY` likely to refer a patient for cataract surgery if the patient is
^p'iX4M employed and less likely to refer a nursing home resident.7
Hg~O0p}[ In the Visual Impairment Project, we did not find that any
M- f)\`I particular subgroup of the population was at greater risk of
|'C{nTX having unoperated cataract. Universal access to health care
]#UyYgPk in Australia may explain the fact that people without
#
U46Au Medicare are more likely to delay cataract operations in the
xB%Felz USA,8 but not having private health insurance is not associated
K):MT[/" with unoperated cataract in Australia.
p6qza @ In summary, cataract is a significant public health problem
G=
[=[o\ in that one in four people in their 80s will have had cataract
b
r"47i surgery. The importance of age-related cataract surgery will
Anpx%NVo increase further with the ageing of the population: the
B&
tU~ number of people over age 60 years is expected to double in
? qn0].
the next 20 years. Cataract surgery services are well
SiD [54OM accessed by the Victorian population and the visual outcomes
*AO^oBeY of cataract surgery have been shown to be very good.
1NP(3yt% These data can be used to plan for age-related cataract
5`$.GV surgical services in Australia in the future as the need for
!y8/El cataract extractions increases.
_L?`C ACKNOWLEDGEMENTS
4t(
V)1+ The Visual Impairment Project was funded in part by grants
piZ0KA" from the Victorian Health Promotion Foundation, the
A4}6hG# National Health and Medical Research Council, the Ansell
&cty&(2p Ophthalmology Foundation, the Dorothy Edols Estate and
g~5$X{ the Jack Brockhoff Foundation. Dr McCarty is the recipient
hpftVEB of a Wagstaff Fellowship in Ophthalmology from the Royal
Ppw0vaJ^ Victorian Eye and Ear Hospital.
/cPezX REFERENCES
aS^
4dEJ 1. Keeffe JE, Taylor HR. Cataract surgery in Australia 1985–94.
b)+;#m Aust. N.Z. J. Ophthalmol. 1996; 24: 313–17.
(Rqn)<<2 2. Sperduto RD, Hiller R. The prevalence of nuclear, cortical,
nLn3kMl4 and posterior subcapsular lens opacities in a general population
C;#-2^h sample. Ophthalmology 1984; 91: 815–18.
wS*An4%G 3. Maraini G, Pasquini P, Sperduto RD et al. Distribution of lens
Wb*A};wE opacities in the Italian-American case–control study of agerelated
Zt3"4d4 cataract. Ophthalmology 1990; 97: 752–6.
f(Vr &X 4. Klein BEK, Klein R, Linton KLP. Prevalence of age-related
_K(w&Kr lens opacities in a population. The Beaver Dam Eye Study.
*]<M%q!<6 Ophthalmology 1992; 99: 546–52.
5Jo><P a 5. Guiffrè G, Giammanco R, Di Pace F, Ponte F. Casteldaccia eye
{)E
)&lL study: prevalence of cataract in the adult and elderly population
Gqe?CM of a Mediterranean town. Int. Ophthalmol. 1995; 18:
zGtWyXP 363–71.
xcBV,[E{ 6. Mitchell P, Cumming RG, Attebo K, Panchapakesan J.
J2rw4L Prevalence of cataract in Australia. The Blue Mountains Eye
[PVem
Study. Ophthalmology 1997; 104: 581–8.
YNEPu:5J 7. Keeffe JE, McCarty CA, Chang WP, Steinberg EP, Taylor HR.
j<H5i} Relative importance of VA, patient concern and patient
gP&G63^ lifestyle on referral for cataract surgery. Invest. Ophthalmol. Vis.
ZbmBwW_ 7 Sci. 1996; 37: S183.
1}O&q6\"J 8. Curbow B, Legro MW, Brenner MH. The influence of patientrelated
O$<m(~[S variables in the timing of cataract extraction. Am. J.
>_R,^iH" Ophthalmol. 1993; 115: 614–22.
teRK#: .P 9. Sletteberg OH, Høvding G, Bertelsen T. Do we operate too
lB7 V4 many cataracts? The referred cataract patients’ own appraisal
8GGC)2 of their need for surgery. Acta Ophthalmol. Scand. 1995; 73:
IP
#w 77–80.
s&>U-7fx" 10. Escarce JJ. Would eliminating differences in physician practice
!CJh6X! style reduce geographic variations in cataract surgery rates?
,{tz%\,% Med. Care 1993; 31: 1106–18.
bSK> p3 11. Livingston PM, Carson CA, Stanislavsky YL, Lee SE, Guest
OrN~ Y#D CS, Taylor HR. Methods for a population-based study of eye
aPR0DZ@
disease: the Melbourne Visual Impairment Project. Ophthalmic
@;^7kt Epidemiol. 1994; 1: 139–48.
Ub>Pl,~' 12. Taylor HR, West SK. A simple system for the clinical grading
UKfC!YR2J8 of lens opacities. Lens Res. 1988; 5: 175–81.
erhxZ|."P 82 McCarty et al.
F<W`zQ46 13. Cochran WG. Sampling Techniques. New York: John Wiley &
am+'j5`Ys Sons, 1977; 249–73.
XGs
d"UW 14. Breslow NE, Day NE. Statistical Methods in Cancer Research. Volume
!)!<.x II – the Design and Analysis of Cohort Studies. Lyon: International
Or({|S9d2 Agency for Research on Cancer; 1987; 52–61.
f@G3,u!]i 15. Australian Bureau of Statistics. 1996 Census of Population and
~7kIe+V Housing. Canberra: Australian Bureau of Statistics, 1997.
-GqMis}c 16. Livingston PM, Lee SE, McCarty CA, Taylor HR. A comparison
R)[ l3 of participants with non-participants in a populationbased
?zS
t epidemiologic study: the Melbourne Visual Impairment
JA")L0a_ Project. Ophthalmic Epidemiol. 1997; 4: 73–82.
vX9B^W||x 17. Programme for the Prevention of Blindness. Global Initiative for the
| e&v;48 Elimination of Avoidable Blindness. Geneva: World Health
Vm3e6Y,K Organization, 1997.
|Z"5zL10 18. Applegate WB, Miller ST, Elam JT, Freeman JM, Wood TO,
L\`uD[g Gettlefinger TC. Impact of cataract surgery with lens implantation
gG>|5R0 on vision and physical function in elderly patients.
>3{l"SPU JAMA 1987; 257: 1064–6.
dx<KZR$!V 19. Steinberg EP, Tielsch JM, Schein OD et al. National Study of
qaj~q(j~C Cataract Surgery Outcomes. Variation in 4-month postoperative
dHAI4Yf4U outcomes as reflected in multiple outcome measures.
]O\m(of
R Ophthalmology 1994; 101:1131–41.
z. 6-D 20. Klein BEK, Klein R, Moss SE. Change in visual acuity associated
H7I&Ky with cataract surgery. The Beaver Dam Eye Study.
L{2KK]IF Ophthalmology 1996; 103: 1727–31.
O6P{+xj$ 21. McCarty CA, Keeffe JE, Taylor HR. The need for cataract
_a?(JzLw5 surgery: projections based on lens opacity, visual acuity, and
:*/'W5iM personal concern. Br. J. Ophthalmol. 1999; 83: 62–5.
T&/ ]| 4 22. Brenner MH, Curbow B, Javitt JC, Legro MW, Sommer A.
iaq+#k@ V Vision change and quality of life in the elderly. Response to
C
`>1x`n cataract surgery and treatment of other ocular conditions.
pKxq\
U Arch. Ophthalmol. 1993; 111: 680–5.
$O)fHD' 23. Schaumberg DA, Dana MR, Christen WG, Glynn RJ. A
Oh|KbM*vS systematic overview of the incidence of posterior capsule
p1O[QQ| opacification. Ophthalmology 1998; 105: 1213–21.
q#mw#Uw- 24. Mordue A, Parkin DW, Baxter C, Fawcett G, Stewart M.
qkLp8/G>pO Thresholds for treatment in cataract surgery. J. Public Health
;:%*h2 Med. 1994; 16: 393–8.
Ul/Uk n$ 25. Norregaard JC, Bernth-Peterson P, Alonso J et al. Variations in
1dl@2CVS indications for cataract surgery in the United States, Denmark,
j&c YRKpz Canada, and Spain: results from the International Cataract
whoQA
}X> Surgery Outcomes Study. Br. J. Ophthalmol. 1998; 82: 1107–11.