Blindness and poverty in India: the way forward

The burden, causes, and determinants of blindness and vision impairment in Asia: An analysis of the Global Burden of Disease Study

Background

Asia accounts for more than half of the world's population and carries a substantial proportion of the global burden of blindness and vision impairment. Characterising this burden, as well as its causes and determinants, could help with devising targeted interventions for reducing the occurrence of blindness and visual impairment.

Methods

Using the Global Burden of Disease Study 2019 database, we retrieved data on the number of disability-adjusted life years (DALYs); crude and age-standardised rates; and the prevalence (with 95% uncertainty intervals (95%UIs)) of blindness and vision loss due to six causes (age-related macular degeneration, cataracts, glaucoma, near-vision impairment, refractive error, and other vision loss) for Asian countries for the period between 1990 and 2019. We defined DALYs as the sum of the years lost due to disability and years of life lost, and calculated age-standardised figures for the number of DALYs and prevalence by adjusting for population size and age structure. We then evaluated the time trend of the disease burden and conducted subgroup analyses by gender, age, geographic locations, and socio-demographic index (SDI).

Results

In 2019, the DALYs and prevalence of blindness and vision loss had risen by 90.1% and 116% compared with 1990, reaching 15.84 million DALYs (95% UI = 15.83, 15.85) and 506.71 million cases (95% UI = 506.68, 506.74). Meanwhile, the age-standardised rate of DALYs decreased from 1990 to 2019. Cataracts, refractive error, and near vision impairment were the three most common causes. South Asia had the heaviest regional disease burden (age-standardised rate of DALYs = 517 per 100 000 population; 95% UI = 512, 521). Moreover, the burden due to cataracts ranked high in most Asian populations. Being a woman; being older; and having a lower national SDI were factors associated with a greater vision loss burden.

Conclusions

The burden due to vision loss remains high in Asian populations. Cataracts, refractive error, and near vision loss were the primary causes of blindness and vision loss. Greater investment in ocular disease prevention and care by countries with lower socioeconomic status is needed, as well as specific strategies targeting cataract management, women and the elderly.

Visual impairment and falls among older adults and elderly: evidence from longitudinal study of ageing in India

BACKGROUND

The present study determines the prevalence and correlates of falls, multiple falls, and injuries, focusing on visual impairment among the older adult and elderly population in India. Additionally, owing to the higher prevalence of falls and visual impairment among women, a sex-stratified analysis has also been done in the present study.

METHODS

The study utilized the data from the first wave of the Longitudinal Ageing Study in India (LASI wave-1), conducted during 2017-2018. Bivariate with chi-square and multivariate analyses were performed to fulfill the objective.

RESULTS

Around 34% of population had low vision (male:30% and female: 38%), while blindness prevalence was 1.63% (males: 1.88% and females: 1.41%). The fall was higher among females and increased across the gender with increasing visual impairment and blindness levels. The unadjusted odds of falls were 16% higher among individuals with low vision and 40% higher among individuals with blindness than with normal vision, and comparatively higher odds among females than males.

CONCLUSION

In summary, falls and visual impairment is public health challenge and needs to be addressed. Visual impairment is preventable in most cases, so it may be a modifiable target for reducing the risk of falls.

Correlation between global prevalence of vision impairment and depressive disorders

PURPOSE

To assess the correlation of the worldwide prevalence of visual impairment and depressive disorders.

METHODS

This is an ecologic study on Global Burden of Disease 2019 data. Global and national prevalence numbers and rates of vision impairment (VI) and depressive disorders were obtained from database. The human development index (HDI) and socio-demographic index (SDI) were derived from international open databases. Main outcome measures were the correlation of the VI and depressive disorders in total and different age, sex, and socioeconomic subgroups.

RESULTS

In 2019, the worldwide prevalence of total VI and total depressive disorders were 9.6% (95% Uncertainty Interval (UI): 8.0-11.3) and 3.8% (95% UI: 3.4-4.2), respectively. The prevalence rates of total VI (r = 0.38, P < 0.001) as well as cataract (r = 0.43, P < 0.001), age-related macular degeneration (AMD) (r = 0.32, P < 0.001), refractive disorders (r = 0.19, P < 0.001) and near vision loss (r = 0.33, P < 0.001) correlated, positively, with dysthymia. In addition, the prevalence rates of glaucoma (r for total depressive disorders = 0.37, P < 0.001 and r for major depressive disorders (MDD) = 0.38, P < 0.001) and AMD (r for total depressive disorders = 0.37, P < 0.001 and r for MDD = 0.28, P < 0.001) had a positive correlation with MDD and total depressive disorders. The correlations remained significant in sociodemographic subgroups.

CONCLUSION

There was a significant correlation between national prevalence rates of VI and ocular disabilities with depressive disorders, worldwide.

Leveraging big data for pattern recognition of socio-demographic and climatic factors in correlation with eye disorders in Telangana State, India

Purpose

Big data is the new gold, especially in health care. Advances in collecting and processing electronic medical records (EMR) coupled with increasing computer capabilities have resulted in an increased interest in the use of big data in health care. Ophthalmology has been an area of focus where results have shown to be promising. The objective of this study was to determine whether the EMR at a multi-tier ophthalmology network in India can contribute to the management of patient care, through studying how climatic and socio-demographic factors relate to eye disorders and visual impairment in the State of Telangana.

Methods

The study was designed by merging a dataset obtained from the Telangana State Development Society to an existing EMR of approximately 1 million patients, who presented themselves with different eye symptoms and diagnosed with several diseases from the years (2011-2019). The dataset obtained included weather and climatic variables to be tested alongside eye disorders. AI creative featuring techniques have been used to narrow down the variables most affected by climatic and demographic factors, with the application of the Cynefin Framework as a guide to simplify and structure the dataset for analysis.

Results

Our findings revealed a high presence of cataract in the state of Telangana, mostly in rural areas and throughout the different weather seasons in India. Males tend to be the most affected as per the number of visits to the clinic, while home makers make the most visit to the hospital, in addition to employees, students, and laborers. While cataract is most dominant in the older age population, diseases such as astigmatism, conjunctivitis, and emmetropia, are more present in the younger age population.

Conclusion

The study appeared useful for taking preventive measures in the future to manage the treatment of patients who present themselves with eye disorders in Telangana. The use of clinical big datasets helps to identify the burden of ocular disorders in the population. The overlaying of meteorological data on the clinical presentation of patients from a geographic region lends insight into the complex interaction of environmental factors on the prevalence of ocular disorders in them.

Population-based Assessment of Vision Impairment in the Elderly Population in Telangana State in India - Policy Implications for Eye Health Programmes

PURPOSE

To investigate the prevalence, causes and risk factors for vision impairment (VI) among the elderly population in Telangana State, India.

METHODS

A population-based cross-sectional study were conducted in four districts. All participants had eye examinations including visual acuity assessment for distance and near, anterior segment examination and non-mydriatic fundus imaging by trained personnel. VI was defined as presenting visual acuity worse than 6/18 in the better eye. Individuals aged ≥60 years were considered as elderly.

RESULTS

In total, 11,238/12,150 (92.5%) individuals aged ≥40 years were examined. Of this, the dataset of 3,640 individuals (32.4%) elderly participants was used for analysis. Among the 3,640 participants, 53.1% were women and 78.1% had no education. The mean age of the participants was 67.8 years (standard deviation: 7 years; range: 60 to 102 years). The age and gender-adjusted prevalence of VI was 32.1% (95% CI: 29.5-34.8). On multivariable analysis, the odds of VI was significantly higher in older age groups, and among those with no education. Gender and district of residence were not associated with the prevalence of VI. Cataract (54.8%) was the leading cause of VI followed by uncorrected refractive errors (37.6%).

CONCLUSIONS AND RELEVANCE

VI was common and largely avoidable in the elderly population in Telangana state in India. Elderly centric eye care including screening for vision loss, provision of cataract surgery and spectacles can be used as strategies to address VI in the elderly.

Prevalence of Retinal Diseases and Associated Risk Factors in an African Population From Mwanza, Tanzania

BACKGROUND AND OBJECTIVE

To determine the prevalence of retinal disease among a population in Mwanza, Tanzania, and to identify relevant risk factors for retinal disorders in this cohort.

PATIENTS AND METHODS

A cross-sectional population-based study was conducted in Mwanza, Tanzania, among patients older than 18 years. Participants completed a demographics survey and underwent an ophthalmic examination that included fundus photography.

RESULTS

Complete data were available for 1,007 (93.8%) of the 1,073 persons examined. The prevalence of vitreoretinal disorders was 22.8% (230/1,007). The leading retinal diseases were age-related macular degeneration (7.0%), hypertensive retinopathy (4.5%), and macular scars (2.7%).

CONCLUSION

This study is the first population-based study of retinal disease in Mwanza. The findings reveal a considerable burden of retinal disease in this region, suggesting a need for trained local ophthalmic personnel and resources. [Ophthalmic Surg Lasers Imaging Retina. 2020;51:S17-S25.].

Socio-economic status, visual impairment and the mediating role of lifestyles in developed rural areas of China

PURPOSE

To examine the impacts of socio-economic status (SES) on visual impairment (VI), and the mediating role of lifestyles in developed rural areas of China.

METHODS

A cross-sectional study was conducted among people living in rural districts of Tianjin, a developed municipality in China. An interviewer-administered survey along with free eye screenings was conducted with participants. The questionnaire included questions about demographic characteristics, SES, medical histories and lifestyles. Presenting visual acuity (PVA) and main causes of VI were identified by ophthalmologists. χ2 test was undertaken to determine whether significant differences (p<0.05) exist between VI and demographic, SES, medical history and lifestyle factors. A stepwise regression method was conducted to investigate whether lifestyles play mediating roles between SES and VI. Multivariable logistic and ordinal logistic regression were used contingent on different types of dependent variables in each regression, and adjusted odds ratio (OR) values were estimated.

RESULTS

Of the 12,233 participants, 6,233 were male (50.59%); the mean age was 34.61 years; 310 (2.54%) had VI. Hypertension, diabetes and cardiopathy were main medical histories, with 1,640 had hypertension (13.41%), 854 had diabetes (6.98%) and 483 had cardiopathy (3.95%). About SES factors, higher education level (Adjusted OR, 0.84; 95% CI, 0.75-0.95) and higher income level (Adjusted OR, 0.54; 95% CI, 0.39-0.76), were significantly associated with VI in a gradient across severity of VI. Lifestyles including smoking (Adjusted OR, 1.55; 95% CI, 1.31-1.83) and drinking (Adjusted OR, 1.36; 95% CI, 1.06-1.74) played mediating roles between SES and VI when considering the full sample. Besides smoking and drinking, reading every week (Adjusted OR, 2.07; 95% CI, 1.53-2.82) and exercising more than 2h every day (Adjusted OR, 0.39; 95% CI, 0.15-1.00) also played mediating roles between SES and VI when considering the subsample (age≥16).

CONCLUSION

This study revealed the crucial impacts of SES factors on VI, and the mediating role played by several lifestyles. Targeted public health interventions for reducing VI should thus be proposed in developed rural areas of China.

Assessment of Horizontal Inequity in Eye Care Utilization in the Iranian Middle-aged Population

PURPOSE

The present study was designed to determine the extent that horizontal inequity was realized regarding eye care utilization in a middle-aged population as well as factors affecting this equity.

METHODS

Data were obtained from a population-based study (Shahroud Eye Cohort Study) in 2009 that included 5190 participants from 40 to 64 years of age. Horizontal inequity was determined based on the following variables: (i) economic status, (ii) eye care service needs, (iii) non-need variables, and (iv) eye care utilization (visiting an ophthalmologist or optometrist). Decomposition analysis of the concentration index based on a nonlinear model and indirect standardization was used to ascertain the contribution of each factor in inequity of eye care utilization.

RESULTS

After adjusting for need variables, the results of our study demonstrated that horizontal inequity in eye care utilization in a middle-aged Iranian population remained positive and significant (horizontal inequity: 0.19; 95% confidence interval: 0.17-0.23) indicating that use of services was focused among participants with a better financial situation. Furthermore, decomposition analysis demonstrated that educational level and economic status had the greatest contribution (54.1% and 41.1%, respectively) in comparison to other variables.

CONCLUSION

This study demonstrated that horizontal inequity exists in eye care utilization among the middle-aged Iranian population.

A review of visual impairment

Visual impairment (VI), a global concern that is likely to escalate with prolonged life expectancies, has gained increasing attention in the realm of eye care. The purpose of this article is to highlight the different aspects of VI, including its definition and characteristics, prevalence, causes and implications. The importance of rehabilitation in individuals with VI is also discussed.

Assessing the impact of a program for late surgical intervention in early-blind children

OBJECTIVE

Many blind children in the developing world are unable to obtain timely treatment due to lack of financial and medical resources. Can public health programs that identify and treat such children several years after the onset of blindness enhance their quality of life? The notion that visual development is subject to an early 'critical period' argues against this possibility. However, there are inadequate empirical data from humans on this issue. To address this need, we examined the quality of life of children living in India and who were treated for early-onset blindness (before one year of age), due to cataracts or corneal opacities.

STUDY DESIGN

Survey study.

METHODS

As part of an ongoing scientific effort named Project Prakash, we screened over 40,000 children in rural northern India to identify those suffering from early-onset blindness. They were provided eye surgeries in a tertiary care ophthalmic center in New Delhi. We subsequently surveyed 64 Prakash children, ranging in age from 5 to 22 years and obtained their responses on a multi-dimensional quality of life questionnaire.

RESULTS

Nearly all of the subjects indicated that their quality of life had improved after treatment. Children reported marked enhancement in their mobility, independence, and safety, and also in social integration. Surprisingly, we found no significant correlations between quality of life metrics and factors such as age at treatment, gender, time since treatment, and pre-surgery and post-surgery acuity.

CONCLUSIONS

A key question for public health policy makers is whether a program of surgical intervention for older blind children is likely to be beneficial, or if the resources are better spent on rehabilitation via vocational training and assistive devices. The marked improvements in quality of life we find in our data strongly argue for the provision of surgical care regardless of a child's age.

Rapid Assessment of Refractive Error, Presbyopia, and Visual Impairment and Associated Quality of Life in Nampula, Mozambique

Introduction

Uncorrected refractive error is the leading cause of visual impairment worldwide and leads to an impaired quality of life. This study was designed to determine the prevalence of uncorrected refractive error and presbyopia, to assess spectacle coverage, and to evaluate visual health-related quality of life among persons aged 15–50 years old in Nampula, Mozambique.

Methods

Participants were assessed using a validated rapid assessment of refractive error protocol, comprised of a demographic questionnaire, a standardized ophthalmic assessment to determine refractive status and spectacle coverage, and a modified vision-related quality of life questionnaire to assess the impact of uncorrected refractive error on participants’ visual health status.

Results

Among the 3,453 respondents, visual impairment prevalence was 3.5% (95%, CI 2.7%–4.2%), with 65.8% of those visually impaired being 35 years of age and older. Uncorrected refractive error prevalence was 2.6% (95%, CI 2.1–3.2%), and was the primary cause of visual impairment among 64.5% of cases. The spectacle coverage for uncorrected refractive error was 0%. Presbyopia prevalence was higher, at 25.8% (95%, CI 12.0–30.5%), with only 2.2% spectacle coverage. Respondents with visual impairment demonstrated statistically significantly lower quality of life scores compared to those without visual problems ( p < 0.01).

Implications for practitioners

The uncorrected refractive error problem and a distinct lack of spectacle coverage for refractive error and presbyopia indicate an urgent need for the development and delivery of a comprehensive refractive error service in the Nampula region of Mozambique.

The Barrie Jones Lecture-Eye care for the neglected population: challenges and solutions

Globally, pockets of 'neglected populations' do not have access to basic health-care services and carry a much greater risk of blindness and visual impairment. While large-scale public health approaches to control blindness due to vitamin A deficiency, onchocerciasis, and trachoma are successful, other causes of blindness still take a heavy toll in the population. High-quality comprehensive eye care that is equitable is the approach that needs wide-scale application to alleviate this inequity. L V Prasad Eye Institute of India developed a multi-tier pyramidal model of eye care delivery that encompasses all levels from primary to advanced tertiary (quaternary). This has demonstrated the feasibility of 'Universal Eye Health Coverage' covering promotive, preventive, corrective, and rehabilitative aspects of eye care. Using human resources with competency-based training, effective and cost-effective care could be provided to many disadvantaged people.

Economic inequality in eye care utilization and its determinants: a Blinder-Oaxaca decomposition

BACKGROUND

The current study aimed to determine eye care utilization, to assess the role of economic inequality in the utilization of eye care services, and to identify its determinants in Shahroud, North of Iran.

METHODS

Of the 6,311 invited people, 5,190 (82.24%) individuals aged 40 to 64 years old participated in the study. A history of a visit by an ophthalmologist or optometrist was considered as eye care utilization. The gap between low- and high-economic groups was decomposed into its determinants using the Oaxaca decomposition method.

RESULTS

Among the participants, 16.32% [95% Confidence Intervals (CI)= 15.31-17.33%] had never been examined by an ophthalmologist or optometrist, and 30.94% (95% CI= 29.69-32.20%) had not undergone an eye examination in the past 5 years. This negative history was significantly higher among female subjects [Odds Ratio (OR)= 1.79, 95% CI= 1.51-2.14], the low-economic group (OR= 2.33, 95% CI= 1.90-2.87), the visually impaired (OR= 1.41, 95% CI= 1.05-1.90), and the uninsured (OR= 1.93, 95% CI= 1.45-2.58). The negative history of eye examination decreased with increasing in age (OR= 0.94, 95% CI= 0.93-0.96) and education (OR= 0.94, 95% CI= 0.92-0.96). In this study, 24.72% (95% CI= 22.30-27.14) of the low-economic group and 9.94% (95% CI= 8.75-11.14) of the high-economic group had no history of eye examination. Decomposition of the gap between the two economic groups showed that education and gender were the most important determinants of inequality.

CONCLUSION

A considerable percentage of adults, even those with visual impairment, do not receive appropriate eye care. There is a definite economic inequality in the community for which poverty per se could be the major cause.

A population-based cross-sectional study of barriers to uptake of eye care services in South India: the Rapid Assessment of Visual Impairment (RAVI) project

OBJECTIVE

To assess the barriers to uptake of eye care services among those with avoidable impairment in the population aged ≥40 years in the South Indian state of Andhra Pradesh.

DESIGN

Cross-sectional study.

SETTING

Community setting.

PARTICIPANTS

Of 7800 participants recruited from one urban and two rural locations using a two-stage cluster random sampling methodology, 7378 (95%) were examined. Eye examinations were conducted using a rapid assessment protocol. Visual impairment (VI) was defined as presenting visual acuity <6/18 in the better eye. For the purpose of this study, VI caused due to cataract or uncorrected refractive error was considered avoidable VI. A validated questionnaire was used to collect information on barriers for uptake of services among those who had avoidable VI.

PRIMARY OUTCOME

Barriers to uptake of services among those with avoidable VI.

RESULTS

The prevalence of avoidable VI was 11.8% (95% CI 11.0% to 12.5%; n=868). Among these, 71.1% (n=617) individuals reported 'person-related' barriers whereas 28.9% (n=251) individuals reported 'service-related' barriers to uptake of services. Among the 'person-related' barriers, the leading barrier was 'lack of perceived need' (61.1%; n=377) for reasons such as old age, good vision in the other eye. This was followed by 'no one to accompany' (20.3%; n=125). Of the 251 individuals who had 'service-related' barriers, lack of affordability was the major barrier (76.1%; n=191) followed by lack of accessibility (12.7%; n=32). Over 11% (n=28) of the individuals were advised to wait for cataract surgery.

CONCLUSIONS

Person-related barriers are more common than service-related barriers in Andhra Pradesh. As the barriers trend more towards 'person-related' phenomenon such as person's attitude and 'felt need' to improve vision, newer and much intensive awareness campaigns are needed to bring about an attitudinal/behavioural change among individuals to improve the uptake of services.

Visual impairment in the South Indian state of Andhra Pradesh: Andhra Pradesh - rapid assessment of visual impairment (AP-RAVI) project

PURPOSE

To assess the prevalence and causes of visual impairment in urban and rural population aged ≥ 40 years in the South India state of Andhra Pradesh.

METHODS

A population based cross-sectional study was conducted in which 7800 subjects were sampled from two rural and an urban locations. Visual Acuity (VA) was assessed using a tumbling E chart and eye examinations were performed by trained vision technicians. A questionnaire was used to collect personal and demographic information and previous consultation to eye care providers. Blindness and moderate Visual Impairment (VI) was defined as presenting VA <6/60 and <6/18 to 6/60 in the better eye respectively. VI included blindness and moderate VI.

RESULTS

Of the 7800 subjects enumerated, 7378 (94.6%) were examined. Among those examined, 46.4% were male and 61.8% of them had no education. The mean age of those examined (51.7 years; standard deviation 10.9 years) was similar to those not examined (52.8 years; standard deviation 9.9 years) (p=0.048). Age and gender adjusted prevalence of VI was 14.3% (95% CI: 13.5-15.0). Refractive errors were the leading cause of VI accounting for 47.6% of all VI followed by cataract (43.7%). Together, they contributed to over 91.3% of the total VI. With multiple logistic regression, the odds of having VI increased significantly with increasing age. Those respondents who had no education were twice (95% CI: 1.7-2.5) more likely to have VI compared to those who were educated. VI was associated with rural residence (OR: 1.3; 95% CI: 1.1-1.6). The association between VI and gender was not statistically significant.

CONCLUSIONS

The visual impairment remains a public health challenge in Andhra Pradesh, most of which can be addressed with relatively straight forward interventions like cataract surgery and spectacles. The eye care services need to be streamlined to address this challenge.

Economic inequality in presenting near vision acuity in a middle-aged population: a Blinder-Oaxaca decomposition

PURPOSE

To investigate economic inequality and its determinants in near vision, in a middle-aged population.

METHODS

In this population-based study, the presenting near vision in the better eye was investigated as the main outcome. If this vision revealed a value ≥1.6 M, the participant was considered to have presenting near vision impairment (PNVI). The effect of variables studied on PNVI was investigated using logistic regression. Economic inequality in PNVI was investigated using the Oaxaca-Blinder decomposition method.

RESULTS

PNVI in the better eye was observed in 18.2% (95% CI 16.8 to 19.6) of participants. The prevalence of PNVI in the high and low economic groups was 11.7% (95% CI 10.3 to 13.0) and 28.5% (95% CI 26.0 to 31.0), respectively. Age and education were observed as the main factors in the explained portion of this gap and were in favour of the high economic group. Gender and eye care utilisation were factors affecting the unexplained portion of this gap and were in favour of the low economic group.

CONCLUSIONS

Economic inequality plays a significant role in PNVI, while age and education are among the main factors affecting this gap. The effect caused by any change in these two factors was found to have a greater effect on women with low economic status.

Prevalence and causes of avoidable blindness and severe visual impairment in a tribal district of Maharashtra, India

BACKGROUND

We present the outcomes of a survey conducted in Nandurbar, a tribal district of Maharashtra, India. It was based on "Rapid Assessment for Avoidable Blindness" methodology and conducted in 2009 in Nandurbar, a tribal district of Maharashtra, India.

MATERIALS AND METHODS

We examined persons of 50 years and older ages. Ophthalmic assistants noted the distant vision [best corrected vision (BCV) and as presented]. Ophthalmologist examined eyes of persons with vision less than 6/18. The principal cause of impairment in each eye and the most "preventable" or "treatable" cause were assigned. We calculated the prevalence rates of bilateral blindness, severe visual impairment (SVI), and moderate visual impairment (MVI).

RESULT

We examined 2,005/2,300 persons (response rate 87.2%). The prevalence of blindness, SVI, and MVI for the BCV was 1.63% (95% CI 1.11-2.15), 5.93% (95% CI 4.96-6.90), and 14.6% (95% CI 13.2-16.1), respectively. The prevalence of blindness, SVI, and MVI for the presented vision was 1.87% (1.32-2.42), 6.72% (95% CI 5.70-7.74), and 19% (95% CI 17.4-20.6), respectively. Unoperated cataract was responsible for 77% of different visual disabilities. The coverage of existing cataract surgery service was 9.4%. Lack of knowledge about cataract surgery was the main cause of unoperated cataract among 41% of interviewed participants with cataract and SVI.

CONCLUSION

Unoperated cataract was the main curable cause of visual disabilities in tribal population of India. Increasing awareness and offering cataract surgeries at affordable cost in the district would reduce visual disabilities.

Population-based cross-sectional study of barriers to utilisation of refraction services in South India: Rapid Assessment of Refractive Errors (RARE) Study

AIM

To assess the barriers to the uptake of refraction services in the age group of 15-49 years in rural Andhra Pradesh, India.

METHODS

A population-based cross-sectional study was conducted using cluster random sampling to enumerate 3300 individuals from 55 clusters. A validated questionnaire was used to elicit information on barriers to utilisation of services among individuals with uncorrected refractive error (presenting visual acuity <6/12 but improving to ≥6/12 on using a pinhole) and presbyopia (binocular near vision <N8 in individuals aged >35 years with binocular distance visual acuity of ≥6/12).

RESULTS

3095 (94%) were available for examination. Those with uncorrected refractive errors cited affordability as the main barrier to the uptake of eye-care services. Among people with uncorrected presbyopia, lack of 'felt need' was the leading barrier.

CONCLUSION

The barriers that were 'relatively easy to change' were reported by those with uncorrected refractive errors in contrast to 'difficult to change' barriers reported by those with uncorrected presbyopia. Together, the data on prevalence and an understanding of the barriers for the uptake of services are critical to the planning of refractive error services.

Prevalence and causes of visual impairment and blindness in an urban Indian population: the Singapore Indian Eye Study

PURPOSE

To describe the prevalence and causes of visual impairment and blindness in an urban Indian population.

DESIGN

Population-based study.

PARTICIPANTS

Ethnic Indians aged more than 40 years living in Singapore.

METHODS

Participants underwent standardized ophthalmic assessments for visual impairment and blindness, defined using best-corrected visual acuity (BCVA) and presenting visual acuity (PVA), according to US and modified World Health Organization (WHO) definitions.

MAIN OUTCOME MEASURES

Unilateral visual impairment or blindness was defined on the basis of the worse eye, and bilateral visual impairment or blindness was defined on the basis of the better eye. Primary causes of visual impairment were determined.

RESULTS

A total of 3400 eligible individuals (75.6% response rate) participated. On the basis of US definitions, the age-standardized prevalence was 0.4% for bilateral blindness (≤20/200, better eye) and 3.4% for bilateral visual impairment (<20/40 to >20/200, better eye). Another 0.3% of bilateral blindness and 13.4% of bilateral visual impairment were correctable with refraction. Cataract was the principal cause of best-corrected bilateral blindness (60.0%) and bilateral visual impairment (65.7%). Other major causes of blindness and visual impairment included diabetic retinopathy, age-related macular degeneration, glaucoma, corneal opacity, and myopic maculopathy.

CONCLUSIONS

The prevalence of bilateral blindness and visual impairment in Indians living in Singapore is lower than estimates from populations living in India, but similar to estimates obtained from Singapore Malay and Chinese populations. Cataract is the leading cause of blindness and visual impairment. One in 20 cases of bilateral blindness and 1 in 10 cases of bilateral visual impairment are attributable to diabetic retinopathy. These data may have relevance to many ethnic Indian persons living outside India.