ABSTRACT
6Rif&W.xy Purpose: To quantify the prevalence of cataract, the outcomes
Q;y4yJ$wI of cataract surgery and the factors related to
6
3PV R" unoperated cataract in Australia.
`B8`<3k/( Methods: Participants were recruited from the Visual
Zs0;92WL Impairment Project: a cluster, stratified sample of more than
Yc
)Dx3 5000 Victorians aged 40 years and over. At examination
=<#++;!I
sites interviews, clinical examinations and lens photography
#jxPh!%9 were performed. Cataract was defined in participants who
(?7}\B\ had: had previous cataract surgery, cortical cataract greater
d7&d
FvG than 4/16, nuclear greater than Wilmer standard 2, or
Wy1.nn[ posterior subcapsular greater than 1 mm2.
@3b @]l5 Results: The participant group comprised 3271 Melbourne
MR@Qn[RdM residents, 403 Melbourne nursing home residents and 1473
fOsvOC rural residents.The weighted rate of any cataract in Victoria
+g1+,?cU was 21.5%. The overall weighted rate of prior cataract
xu]Kt+QnSk surgery was 3.79%. Two hundred and forty-nine eyes had
2}.~
6EU/ had prior cataract surgery. Of these 249 procedures, 49
-
?
i (20%) were aphakic, 6 (2.4%) had anterior chamber
0Nk!.gY intraocular lenses and 194 (78%) had posterior chamber
|{%$x^KyJ intraocular lenses.Two hundred and eleven of these operated
s nNd7v.U6 eyes (85%) had best-corrected visual acuity of 6/12 or
<O-R better, the legal requirement for a driver’s license.Twentyseven
eAQ-r\h'2 (11%) had visual acuity of less than 6/18 (moderate
ofYZ!-V vision impairment). Complications of cataract surgery
K1;b4Sl?A caused reduced vision in four of the 27 eyes (15%), or 1.9%
j@UE#I|h of operated eyes. Three of these four eyes had undergone
%l%2 hvGZ intracapsular cataract extraction and the fourth eye had an
i}|jHlv opaque posterior capsule. No one had bilateral vision
}KftVnD? impairment as a result of cataract surgery. Surprisingly, no
(v0Q.Q@< particular demographic factors (such as age, gender, rural
=
~*Vfx residence, occupation, employment status, health insurance
~e]l status, ethnicity) were related to the presence of unoperated
-\Z`+k Y?p cataract.
X
VH(zJ Conclusions: Although the overall prevalence of cataract is
9A`^ ( quite high, no particular subgroup is systematically underserviced
(enOj0 in terms of cataract surgery. Overall, the results of
uE%2kB*] cataract surgery are very good, with the majority of eyes
4^ 0CHy achieving driving vision following cataract extraction.
t`eIkq|NxI Key words: cataract extraction, health planning, health
G8Ow;:Ro
services accessibility, prevalence
mZnsr@KF INTRODUCTION
NXS$w{^ Cataract is the leading cause of blindness worldwide and, in
J'I1NeK Australia, cataract extractions account for the majority of all
fNrpYR X ophthalmic procedures.1 Over the period 1985–94, the rate
e?GzvM'2 of cataract surgery in Australia was twice as high as would be
|$GPJaNqa expected from the growth in the elderly population.1
3?+t%_[ Although there have been a number of studies reporting
XE;'K`% the prevalence of cataract in various populations,2–6 there is
h54\
\Ci little information about determinants of cataract surgery in
}n,LvA@[0 the population. A previous survey of Australian ophthalmologists
<c,iu{: showed that patient concern and lifestyle, rather
d]?fL&jr than visual acuity itself, are the primary factors for referral
M pz9}[`3g for cataract surgery.7 This supports prior research which has
Ga
<=Di): shown that visual acuity is not a strong predictor of need for
Yqt~h cataract surgery.8,9 Elsewhere, socioeconomic status has
g6][N{xW0 been shown to be related to cataract surgery rates.10
raMtTL+ To appropriately plan health care services, information is
c'bh`
H4 needed about the prevalence of age-related cataract in the
JFkx=![ community as well as the factors associated with cataract
ftV~!r surgery. The purpose of this study is to quantify the prevalence
YTfi g{a of any cataract in Australia, to describe the factors
#1'p?%K. related to unoperated cataract in the community and to
9SU/86|N describe the visual outcomes of cataract surgery.
Xw16
2/:h METHODS
K8v@) Study population
0p*Oxsy Details about the study methodology for the Visual
WjvgDNk Impairment Project have been published previously.11
DeQZDY // Briefly, cluster sampling within three strata was employed to
qMd4awB
R recruit subjects aged 40 years and over to participate.
z;&J9r$` Within the Melbourne Statistical Division, nine pairs of
<CS,v)4,nH census collector districts were randomly selected. Fourteen
TO/SiOd nursing homes within a 5 km radius of these nine test sites
Ai`0Ud,M@ were randomly chosen to recruit nursing home residents.
Ed#Hilk' Clinical and Experimental Ophthalmology (2000) 28, 77–82
8`|Z9umW* Original Article
;F/w&u.n Operated and unoperated cataract in Australia
T^2o'_: Catherine A McCarty PhD, MPH, Mukesh B Nanjan PhD, Hugh R Taylor MD
XU`vs`/ Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
)jw!,"_4 n Correspondence: Dr Cathy McCarty MPH, Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, 32 Gisborne Street, East Melbourne,
b C"rQJg Victoria 3002, Australia. Email:
cathy@cera.unimelb.edu.au 2KNs,4X@ 78 McCarty et al.
2=n,{rkmj% Finally, four pairs of census collector districts in four rural
Mw6
Mt
Victorian communities were randomly selected to recruit rural
tG0
&0` residents. A household census was conducted to identify
cu4 |!s`# eligible residents aged 40 years and over who had been a
58PL@H~@0 resident at that address for at least 6 months. At the time of
+"VXw2R_e the household census, basic information about age, sex,
J>+~//C country of birth, language spoken at home, education, use of
p<Vj<6.=? corrective spectacles and use of eye care services was collected.
+ ;B K|([# Eligible residents were then invited to attend a local
w2V:g$~, examination site for a more detailed interview and examination.
L#MMNc+ The study protocol was approved by the Royal Victorian
MVp+2@)}s Eye and Ear Hospital Human Research Ethics Committee.
!Ic~_7" Assessment of cataract
hhJs$c( A standardized ophthalmic examination was performed after
KY9@2JG pupil dilatation with one drop of 10% phenylephrine
^{64b hydrochloride. Lens opacities were graded clinically at the
-D
wO*f time of the examination and subsequently from photos using
*,Sa*-7( the Wilmer cataract photo-grading system.12 Cortical and
E~`<n]{G-C posterior subcapsular (PSC) opacities were assessed on
9@YhAj
retroillumination and measured as the proportion (in 1/16)
Gp1?drF6 of pupil circumference occupied by opacity. For this analysis,
x#'v}(v cortical cataract was defined as 4/16 or greater opacity,
Mu$"fYKf" PSC cataract was defined as opacity equal to or greater than
f<Yg_ TG 1 mm2 and nuclear cataract was defined as opacity equal to
,BlNj^
5f or greater than Wilmer standard 2,12 independent of visual
{BD G;e acuity. Examples of the minimum opacities defined as cortical,
#6 M3BF nuclear and PSC cataract are presented in Figure 1.
CD)JCv Bilateral congenital cataracts or cataracts secondary to
D3C3_
@* intraocular inflammation or trauma were excluded from the
$kY ]HI analysis. Two cases of bilateral secondary cataract and eight
6f;20dn6 cases of bilateral congenital cataract were excluded from the
KH9D}, analyses.
U;FJSy A Topcon® SL5 photo slit-lamp (Topcon America Corp.,
jJe?pT]o Paramus, NJ, USA) with a 0.1 mm slit beam of 9.0 mm in
m 8P`n height set to an incident angle of 30° was used for examinations.
8]l(D Ektachrome® 200 ASA colour slide film (Eastman
fD2)/5j1 Kodak Company, Rochester, NY, USA) was used to photograph
0W]vK$\F* the nuclear opacities. The cortical opacities were
X=%e'P*X photographed with an Oxford® retroillumination camera
QJU\YH%} (Marcher Enterprises Ltd, Hereford, UK) and T-MAX® 400
9+I/b
l4 film (Eastman Kodak). Photographs were graded separately
I$oqFF|D by two research assistants and discrepancies were adjudicated
noO#o+
Jg# by an independent reviewer. Any discrepancies
>ui;B$= between the clinical grades and the photograph grades were
U,Z7nH3_ resolved. Except in cases where photographs were missing,
Qv1cf the photograph grades were used in the analyses. Photograph
m[Cp
G=32B grades were available for 4301 (84%) for cortical
Er<!8;{?
cataract, 4147 (81%) for nuclear cataract and 4303 (84%)
+RyV"&v for PSC cataract. Cataract status was classified according to
qzii[Mf the severity of the opacity in the worse eye.
REJHh\:.77 Assessment of risk factors
j
-7aJj% A standardized questionnaire was used to obtain information
\n^;r|J7k about education, employment and ethnic background.11
yhd]s0(! Specific information was elicited on the occurrence, duration
!>)o&sM and treatment of a number of medical conditions,
7
/XfPF including ocular trauma, arthritis, diabetes, gout, hypertension
Gk:k
px and mental illness. Information about the use, dose and
OZQN&7 duration of tobacco, alcohol, analgesics and steriods were
;e6-* collected, and a food frequency questionnaire was used to
Pdk#"H-j determine current consumption of dietary sources of antioxidants
`pfRY! and use of vitamin supplements.
^CP>|JWD^ Data management and statistical analysis
R
_Z9
aQ Data were collected either by direct computer entry with a
I8{
mk h questionnaire programmed in Paradox© (Carel Corporation,
gB]jLe Ottawa, Canada) with internal consistency checks, or
q$'[&&