The
Impact of Successful Cataract Surgery on Quality of Life, Household Income and
Social Status in South India
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0044268
(www.karmayog.org) – (25.09.2013)
Robert P. Finger, David G. Kupitz* E-mail: robertfinger@gmx.net
Affiliations: Department of Ophthalmology, University of
Bonn, Bonn, Germany, Centre for Eye Research Australia, Royal Victorian Eye and
Ear Hospital, University of Melbourne, Melbourne, Australia
David G. Kupitz ; Affiliation: Department of Ophthalmology,
University of Bonn, Bonn, Germany
Eva Fenwick; Affiliation: Centre for Eye Research
Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne,
Melbourne, Australia
Bharath Balasubramaniam; Affiliation: Sankara Eye Care
Institutions, Coimbatore, India
Ramanathan V. Ramani; Affiliation: Sankara Eye Care
Institutions, Coimbatore, India
Frank G. Holz; Affiliation: Department of Ophthalmology,
University of Bonn, Bonn, Germany
Clare E. Gilbert; Affiliation: International Centre for Eye
Health, London School for Hygiene and Tropical Medicine, London, United Kingdom
Background
To explore the hypothesis that sight restoring cataract
surgery provided to impoverished rural communities will improve not only visual
acuity and vision-related quality of life (VRQoL) but also poverty and social
status.
Methods
Participants were recruited at outreach camps in Tamil Nadu,
South India, and underwent free routine manual small incision cataract surgery
(SICS) with intra-ocular lens (IOL) implantation, and were followed up one year
later. Poverty was measured as monthly household income, being engaged in
income generating activities and number of working household members. Social
status was measured as rates of re-marriage amongst widowed participants. VRQoL
was measured using the IND-VFQ-33. Associations were explored using logistic
regression (SPSS 19).
Results
Of the 294 participants, mean age ± standard deviation (SD)
60±8 years, 54% men, only 11% remained vision impaired at follow up (67% at
baseline; p<0.001). At one year, more participants were engaged in income
generating activities (44.7% to 77.7%; p<0.001) and the proportion of
households with a monthly income <1000 Rps. decreased from 50.5% to 20.5%
(p<0.05). Overall VRQoL improved (p<0.001). Participants who had
successful cataract surgery were less likely to remain in the lower categories
of monthly household income (OR 0.050.22; p<0.02) and more likely to be
engaged in income earning activities one year after surgery (OR 3.28; p =
0.006). Participants widowed at baseline who had successful cataract surgery
were less likely to remain widowed at one year (OR 0.02; p = 0.008).
Conclusion
These
findings indicate the broad positive impact of sight restoring cataract surgery
on the recipients as well as their families lives. Providing free high
quality cataract surgery to marginalized rural communities will not only
alleviate avoidable blindness but also – to some extent – poverty in the long
run.
Citation: Finger RP, Kupitz DG, Fenwick E, Balasubramaniam
B, Ramani RV, et al. (2012) The Impact of Successful Cataract Surgery on
Quality of Life, Household Income and Social Status in South India. PLoS ONE
7(8): e44268. doi:10.1371/journal.pone.0044268
Editor: John E. Mendelson, California Pacific Medicial
Center Research Institute, United States of America
Received: May 17, 2012; Accepted: July 31, 2012; Published:
August 31, 2012
Copyright: © Finger et al. This is an open-access article
distributed under the terms of the Creative Commons Attribution License, which
permits unrestricted use, distribution, and reproduction in any medium,
provided the original author and source are credited.
Funding: The project was supported by the German
Ophthalmological Society (DOG), the German Research Foundation (DFG) and the
Indian Academy of Science. The funders had no role in study design, data
collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no
competing interests exist.
Globally, cataract is the
main cause of blindness with the vast majority of cataract blind living in low
income countries (LIC) [1]
and approximately eight million of those blind from cataract live in India. [2],
[3]
Blindness and poverty are closely linked in a cyclic relationship, as poverty
can lead to blindness from conditions such as cataract or trachoma, and
blindness can worsen poverty through reduced economic productivity. [4],
[5],
[6],
[7],
[8]
Furthermore visual impairment leads to reduced quality of life (QoL) [9],
[10],
poorer general health [11],
lower social status and increased mortality. [12],
[13]
Cataract surgery is a highly cost effective intervention [14]
and cataract surgical rates have increased considerably over the past decade in
many LICs, including India. However, the quality of provided cataract surgery
is not always optimal, with a considerable proportion of patients still blind
or vision impaired after cataract surgery in a LIC setting. [15],
[16]
Restoration of vision, for example through cataract surgery, has been
demonstrated to enhance quality of life and participation in daily living and,
more recently, to improve household economic status. [4].
The Millennium
Development Goals (MDGs) are eight international development goals which the
United Nations (UN) and all its member states aim to achieve by the year 2015.
They include eradicating extreme poverty, gender equality, and developing a
global partnership for development. [17]
With its high success rates and cost-effectiveness, it is likely that the
provision of cataract surgery may contribute towards reducing poverty as part
of the MDGs.
Against this background,
we assessed the impact of successful first eye cataract surgery on poverty,
social status and vision-related QoL (VRQoL) in South India. We hypothesized
that successful cataract surgery would reduce poverty, and improve VRQoL and
social status. This information is important for the MDGs to achieve their
goals and it may also help in allocating resources to ascertain high quality
cataract surgical outcomes.
Ethics Statement
Ethical approval was
obtained from the ethics committees of Sankara Eye Care Services and the
University of Bonn. The study adhered to the tenets of the declaration of
Helsinki. Every participant gave informed, written (signature or thumb imprint)
consent.
This prospective
study, took place from March 2009 until July 2010 in Tamil Nadu, India. Tamil
Nadu is an industrialized and populous state (population 62 million in 2001)
with the largest urban conglomeration in India. [18]
However, there are still poor, rural areas, which are underserviced as
providers tend to be concentrated in cities. The cataract surgical rate in
Tamil Nadu is above the Indian average, being approximately 4000 cataract
operations per million population per year. [19]
This study was embedded within routine services provided by one community
eyecare provider, Sankara Eye Care Services, Coimbatore. The cataract outreach
program operated by Sankara has been described in detail elsewhere. [20].
Recruitment and Follow Up
Participants who
were visually impaired from cataract and had not undergone prior cataract
surgery in any eye were eligible. Persons who were classified as poor, aged 40
years or more, and eligible for first eye cataract surgery were recruited.
Visual impairment was defined as less than 6/60 (logarithm of minimum angel of
resolution (LogMAR) 1.0) in the eye assigned for surgery.
Recruitment took
place at the base hospital after participants had been assessed at outreach eye
clinics, which are regularly conducted. Those who agreed to participate were
interviewed and underwent a full eye examination before undergoing cataract
surgery. Patients transport, surgery, and inpatient hospital stays were
provided free by the hospital as patients all fell under the poverty threshold
(defined below). After cataract surgery, patients were given eye drops,
transported back to the outreach site and told to attend the next outreach
clinic (usually a month later) for a follow up assessment of the cataract
surgery. If they failed to attend they were sent a reminder by mail. Follow-up
data collection for the study occurred at the patients homes at 1 year follow
up by community eye health workers local to the area who are employed full-time
by Sankara.
Ocular Assessment and Cataract Surgery
Preoperative
assessment included distance visual acuity (DVA) measurement using a LogMAR
numbers or tumbling E chart at six meters without correction or with habitual
correction and with pinhole. Participants underwent a basic eye examination by
an ophthalmologist to determine the cause of visual loss and underwent a more
detailed eye examination, including pupil dilation, if the cause of visual loss
could not be determined. Only participants for whom cataract was the main cause
of visual impairment were included. At follow up, DVA was tested using the same
chart at six meters with habitual correction or uncorrected and with pinhole.
Manual small
incision cataract surgery (SICS) with implantation of an intraocular lens (IOL)
(rigid, single piece PMMA implant) under parabulbar anaesthesia was performed
on all participants. IOL power was determined for each individual using manual
keratometry (Bausch and Lomb) and an ocular ultrasound A scan (Echorule 2,
Biomedix Optotechnik & Devices, India).
Measures of Poverty
Participatory
approaches in ranking wealth have been found to yield useful data and valid
information on household wealth. [21],
[22]
The economic part of the baseline questionnaires was extensively discussed with
key informants and patients in focus groups prior to the current study in order
to reflect meaningful and culturally appropriate measures of poverty. Household
income is commonly considered a gold standard measure of current socioeconomic
position. [22]
The most commonly used definition of global poverty is the absolute poverty
line set by the World Bank, based on income and/or consumption (poverty $2 and
extreme poverty $1 a day or less). [23]
The Indian government defined poverty as less than Indian Rupees (Rs). 560 per
month in urban areas and Rs. 368 in rural areas in 2006 [24]
although definitions used by state governments may vary. In this study, poverty
was defined as access to less than Rs. 1200 a month, either as personal (sole
earner) or household income. This threshold is in agreement with Tamil Nadu
state policy where governmental ration cards are issued when the monthly
household income is less than Rs. 1200 (approx. US$25).
In the current study
poverty was measured through self-reported monthly household income, employment
status, occupation and number of working household members. As asset ownership
was unlikely to change over the 1-year follow up period and could thus not
reflect the impact of successful first eye cataract surgery, it was not
assessed in this study. [5]
During the baseline interview, participants were encouraged to discuss monthly
household income with accompanying household members and include all sources of
income, monetary and non-monetary into the final estimate. As blind persons
have been found to be more likely to be unemployed and, if employed, to work
more often in low wage jobs [13],
we recorded employment status and occupation of all participants at baseline
and follow up. In addition, the number of working household members was
recorded, as households with disabled members generally have less members
involved in income generating activities of any kind. [13]
Working was defined as being involved in activities which directly or
indirectly generate income.
Measures of Social Status
Disability,
including blindness, leads to social exclusion and stigmatization which in turn
impedes access to social networks and formal services or social institutions. [13]
Widowers and even more so widows are particularly affected by this societal
response in India, and have little resources at their disposal to cope with
disability. [13]
More disabled women than men are unmarried or do not remarry once widowed in
India. [25]
As social status or stigmatization is difficult to measure [26],
we assessed whether participants who were widowed at baseline remarried
following cataract surgery as a proxy of decreasing stigma and increasing
societal esteem as well as an improved financial outlook of the individual or
household.
Vision-related Quality of Life
VRQoL was measured
using the IND-VFQ-33, a structured questionnaire which contains 33 questions
(items) related to the degree of difficulty in performing vision-dependent
activities (e.g., reading, climbing stairs), psychosocial impact (e.g. fear,
anxiety) and visual symptoms (e.g. glare, pain). [27],
[28]
The original IND-VFQ-33 questionnaire was developed and extensively validated
in the same Indian state (Tamil Nadu), thus no cultural or linguistic
adaptation was necessary. [27]
In the current study, we performed Rasch analysis to assess the measurement
properties of the IND-VFQ-33 in our sample population over time.
Sample Size Calculation
As no data were
available to estimate the effect of cataract surgery on household income or the
rate of re-marriage, we based the sample size calculations on reported changes
in per capita expenditure (PCE) following cataract surgery. [5]
The observed change was of a similar magnitude in all cases regardless of
whether patients were blind, severely or moderately visually impaired at
baseline. Assuming an odds ratio of 1.6 for an improvement in categories of
household income, with a power of 0.8 at a significance level of p = 0.05, we
would need 293 participants (G*Power 3 [29]).
Accounting for a loss of 10% to follow up, we aimed to recruit 330
participants.
Psychometric Evaluation of the IND-VFQ-33
We have reported the
process of psychometric evaluation of the IND-VFQ-33 using Rasch analysis in
more detail elsewhere. [10]
In brief, Rasch analysis is a modern psychometric method that mathematically
describes the interaction between respondents and test items. We performed
Rasch analysis using Winsteps software (version 3.68), Chicago, Illinois, USA. [30]
It was important to establish that differences between the IND-VFQ scores at
baseline and follow-up are valid indicators of changes over time. [31]
Consequently, the baseline and follow-up data were stacked and the absence of
differential item functioning (DIF) was used to establish invariance over time.
Any change in VRQoL scores on an individual level was considered clinically
meaningful if it was larger than approximately half the standard deviation of
the overall mean. This is generally considered to be a useful estimate of a
clinically meaningful difference [32],
[33],
and has repeatedly been used to rate the meaningfulness of change in parameters
such as VRQoL or vision-specific functioning. [10].
Statistical Analysis
The SPSS statistical
software (Version 19.0, SPSS Science, Chicago, IL) was used to analyze the
data. Participants lost to follow up were excluded from all analyses. Descriptive
statistical analyses were performed to characterize the participants
sociodemographic, clinical and IND-VFQ-33 data. Logistic regression (binary and
multinomial) models were conducted to determine the independent factors
associated with measures of poverty, social status and VRQoL.
Visual acuity was
converted into LogMAR for analysis. Successful cataract surgery was defined as
a VA improvement equal or better than 20/63 (LogMAR 0.5). In order to
demonstrate the impact of cataract surgery, analyses were based on successful
cataract surgery, rather than the presence or absence of vision impairment at
follow-up, as these two variables contain the same information. In 80% of cases
the operated eye was the better eye at follow up.
Socio-demographics and Clinical Characteristics of the
Participants
A total of 313
individuals were recruited at baseline. 19 (6%) patients were lost to follow up
and a further 21 (7%) participants who underwent second eye cataract surgery
during follow up were excluded from all but the descriptive analyses. Baseline
characteristics of patients lost to follow up were not significantly different
(p>0.05) with regards to age, gender, better eye VA, household size or
income. The final study sample at baseline thus comprised 294 participants with
a mean ± SD age of 60±8 years. Just under half of the participants were women
(46%, Table 1).
Vision significantly improved after cataract surgery (better eye LogMAR 0.7
(baseline) to 0.3 (follow up), p<0.001), and only 11% of patients remained
vision impaired compared to 67% at baseline, p<0.001.
Table 1. Characteristics of the sample at baseline and 1
year follow up.
doi:10.1371/journal.pone.0044268.t001
Measures of Poverty
Monthly household
income increased to at least the next better category in 122 persons (45.5%)
with most participants reporting to be in the Rs 10013000 category at follow
up (Table 1,
p<0.001). The mean number of working household members significantly
increased at follow up (0.97 to 1.49, p<0.001, Table 1).
Similarly, the number of participants engaged in income generating activities
increased from 128 (44%) at baseline to 225 (77%, p<0.001) at follow up,
with the largest increase seen in the unskilled, daily wage category (Table 1).
The number of participants reported to not work due to vision problems
decreased from 76 at baseline to 4 at follow up.
Participants who had
successful cataract surgery were significantly more likely to report a higher
monthly household income 1 year after cataract surgery. Compared to the highest
income category (>3000 Rs./month), participants were about five times (OR
0.22, 95%CI 0.080.62; p = 0.004) less likely to report a monthly household
income of 01000 Rs. and about twenty times less likely to report an income of
>10003000 Rs. (OR 0.05; 95%CI <0.010.64; p = 0.021, Table 2).
Participants who had successful cataract surgery were more likely to be engaged
in income earning activities one year after surgery (OR 3.28; 95% CI 1.407.82;
p = 0.006, Table 2).
Table 2. Impact of successful cataract surgery on marital
status and measures of poverty at follow up.
doi:10.1371/journal.pone.0044268.t002
Social Status
Participants who had
successful cataract surgery were less likely to remain widowed at one year (OR
0.02; 95% CI <0.010.35; p = 0.008, Table 3).
At baseline, 208 (71%) participants were married, and 80 (27%) widowed or
single (Table 1).
Over the course of the year, 28 participants remarried, while 47 participants
remained widowed (5 lost to follow up, Table 3).
Stratifying this by gender, nine out of 13 widowers (69%) and 19 out of 62
widows (31%) remarried over the course of the study.
Table 3. Characteristics of participants who re-married and
participants who were still widowed/single at 1 year (5 participants lost to
follow up).
doi:10.1371/journal.pone.0044268.t003
Vision-related Quality of Life
The psychometric
properties of the IND-VFQ-33 are summarized in table S1.
The IND-VFQ-33 was split into four subscales, mobility, activity limitations,
psychosocial impact and visual symptoms. All subscales fit the Rasch model (table S1).
However, the visual symptoms subscale was left out of all further analyses as
it was not felt to add any essential information. All other subscales
demonstrated an improvement in VRQoL after cataract surgery (all p=0.001, Table 1).
Having had successful cataract surgery was independently associated with higher
reported mobility, less activity limitations and better psychosocial impact
(all p<0.05; Table 4).
Marital or work status was not associated with any of the subscale scores.
Participants reported better emotional well-being with an improvement of
monthly household income at one year (OR 31, p = 0.034, Table 4).
Table 4. Factors associated with patient-reported quality of
life at 1 year in generalized linear models, adjusted for age, gender and
education.
doi:10.1371/journal.pone.0044268.t004
Persons who underwent
successful cataract surgery reported better visual acuity and increased VRQoL
in South India. Successful cataract surgery also increased the likelihood to be
engaged in an income earning activity, report a higher monthly household income
and report a higher number of working household members one year on. In
addition, widowed or single participants who had successful cataract surgery
were more likely to have remarried over the one year follow up period. These
findings emphasize the need for high quality cataract surgery services, as
unsuccessful cataract surgery may not only lead to no improvements in vision
and VRQoL, but may also deprive patients of a possible future reduction of
poverty at the household level and their chance to re-marry in case of
widowhood.
Overall, our findings are
in line with other studies, where blindness, in particular from cataract, and
poverty have been found to be intricately linked. [4],
[6],
[7],
[34]
However, there is a dearth of literature regarding the non-ocular impact of
cataract surgery in low income countries. [5]
Previous studies have reported that cataract surgery may lead to an improvement
in VRQoL [35],
per capita expenditure [5]
and an increase in time spent on productive activities. [36]
These non-ocular outcomes of cataract surgery are reflected by our findings of
an increase in VRQoL, monthly household income, the number of working household
members and the likelihood to be engaged in income generating activities one
year after cataract surgery.
Several studies have
found poverty to be a barrier to accessing cataract surgery services in India
and elsewhere. [37],
[38],
[39]
In addition, poor surgery outcomes are very likely to discourage acceptance of
available cataract surgery services. [7],
[20]
Given the important positive outcomes of cataract surgery found in this study,
increased efforts are needed to encourage greater acceptance of offered
cataract surgery services. Such services should ideally be of high quality and
provided regularly by the same provider in the same vicinity, and tailored to
the needs of impoverished communities. [20].
The authors are unaware
of any other study which has accessed the impact of a vision-restoring
intervention on social status in blind persons in South Asia. In our study,
successful cataract surgery, i.e. sight restoration to levels above vision
impairment, was associated with an increased likelihood of being remarried a
year later if widowed at baseline. Based on published studies, one can assume a
rate of remarriage after being widowed of 620% for women and 6065% for men of
all ages over their remaining life span in South India. [40]
Unfortunately, no reports of how an existing disability affects rates of remarriage
in India are available. Thus, reported rates only reflect rates of remarriage
in the general population. In our sample, these high rates of re-marriage were
observed in an older population during a one-year follow-up, which increases
the probability of the observed rates being higher than in the general
population. Whether the positive economic impact of successful cataract surgery
highlighted above increases the likelihood of remarriage, or whether it is
reduced stigma due to sight restoration, or a combination of these, is
difficult to assess. In either case, our results suggest that successful
cataract surgery may increase the likelihood of widowed persons remarrying.
However, as our observations are based on a small sample and a limited
follow-up with no control group, they have to be interpreted with caution.
Nevertheless, this finding has a range of positive implications, as widowhood
is associated with adverse health impacts, loss of opportunities to engage in
income generating activities and loss of societal esteem. [41].
Strengths of our study
include the provision of uniform cataract surgery of high quality with IOL
implantation, with good surgical outcomes, detailed visual acuity data, little
attrition to follow up and culturally appropriate and well validated
questionnaires. Moreover, being embedded into routine service provision of
Sankara Eye Care Services in Coimbatore, our sample is representative of the
communities served by this service provider in Tamil Nadu, South India.
Economic data were collected at the individual and household level, rather than
inferred from district or other regional approximations such as postcodes or census
data which increases accuracy. [6],
[42]
During the one year follow-up, no new government or NGO funded programs
increasing options to be engaged in income generating activities were
implemented in the area. To the authors knowledge, no new factory was opened
or other large employer moved into the area, either. The use of Rasch analysis,
an important step in modern scale validation, to assess the measurement
properties of the IND-VFQ-33 is another strength of this study. [10]
Moreover, as the IND-VFQ-33 was developed using input primarily from cataract
patients in Tamil Nadu, [28]
the item content is likely to be very appropriate for this sample.
Conversely, our study is
limited by a relatively small sample size, and a relatively short follow up to
assess the long term impact of cataract surgery on VRQoL, poverty and social
status. The lack of a non-operated control group makes it difficult to
generalize results. However, other case-control studies have demonstrated the
overall impact of cataract surgery compared to no surgery. [4]
Also, our measures of poverty differ from other studies assessing the
association of blindness and poverty, which limits comparability of our
findings. Assessing the impact of successful cataract surgery on rates of
re-marriage is inherently difficult and our results have to be interpreted with
caution. However, overall, our results compare well to other studies as well as
studies assessing rates of re-marriage based on Indian census data. [40].
In conclusion, successful
cataract surgery restores not only vision and improves VRQoL, but enables
previously visually impaired persons to restart work, leads to a higher monthly
household income, and more members of the household being engaged in income
earning activities. In addition, it makes re-marriage amongst widowed elderly
persons more likely. Thus, it is a public health imperative to provide high
quality cataract surgery to impoverished communities in developing countries as
part of achieving the MDGs.
The investigators thank both the staff at the
Sankara Eye Centre in Coimbatore, who conducted the field work and translated
and transcribed the data, and all participants for their time and invaluable
contribution.
Conceived and designed
the experiments: RPF DGK BB RVR. Performed the experiments: RPF DGK BB RVR.
Analyzed the data: RPF DGK EF. Contributed reagents/materials/analysis tools:
RPF DGK EF BB RVR FGH CG. Wrote the paper: RPF DGK EF BB RVR FGH CG.
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