Rapid assessment methods in eye care: an overview

Risk factors for cardiometabolic health in Ghana: Cardiometabolic Risks Study Protocol-APTI Project

Introduction

Cardiometabolic diseases are rapidly becoming primary causes of death in developing countries, including Ghana. However, risk factors for these diseases, including obesity phenotype, and availability of cost-effective diagnostic criteria are poorly documented in an African-ancestry populations in their native locations. The extent to which the environment, occupation, geography, stress, and sleep habits contribute to the development of Cardiometabolic disorders should be examined.

Purpose

The overall goal of this study is to determine the prevalence of undiagnosed diabetes, prediabetes, and associated cardiovascular risks using a multi-sampled oral glucose tolerance test. The study will also investigate the phenotype and ocular characteristics of diabetes and prediabetes subgroups, as well as determine if lifestyle changes over a one-year period will impact the progression of diabetes and prediabetes.

Methods and analysis

The study employs a community-based quasi-experimental design, making use of pre- and post-intervention data, as well as a questionnaire survey of 1200 individuals residing in the Cape Coast metropolis to ascertain the prevalence and risk factors for undiagnosed diabetes and prediabetes. Physical activity, dietary habits, stress levels, sleep patterns, body image perception, and demographic characteristics will be assessed. Glucose dysregulation will be detected using oral glucose tolerance test, fasting plasma glucose, and glycated hemoglobin. Liver and kidney function will also be assessed. Diabetes and prediabetes will be classified using the American Diabetes Association criteria. Descriptive statistics, including percentages, will be used to determine the prevalence of undiagnosed diabetes and cardiovascular risks. Inferential statistics, including ANOVA, t-tests, chi-square tests, ROC curves, logistic regression, and linear mixed model regression will be used to analyze the phenotypic variations in the population, ocular characteristics, glycemic levels, sensitivity levels of diagnostic tests, etiological cause of diabetes in the population, and effects of lifestyle modifications, respectively. Additionally, t-tests will be used to assess changes in glucose regulation biomarkers after lifestyle modifications.

Ethics and dissemination

Ethics approval was granted by the Institutional Review Board of the University of Cape Coast, Ghana (UCCIRB/EXT/2022/27). The findings will be disseminated in community workshops, online learning platforms, academic conferences and submitted to peer-reviewed journals for publication.

Prevalence of visual impairment, uncorrected refractive errors and effective refractive error coverage in Koshi Province, Nepal - Rapid Assessment of Refractive Errors

BACKGROUND/OBJECTIVE

To determine the prevalence of visual impairment (VI), uncorrected refractive errors (URE), and effective refractive error coverage among individuals aged 15-50 years in Koshi Province, Nepal.

METHODS

A population-based cross-sectional study was conducted in Koshi Province in which 4800 participants were selected from 80 clusters. The study teams visited the selected households and conducted eye examinations. This included monocular unaided (and aided) visual acuity assessment using a Snellen chart with tumbling E optotypes at a distance of 6 meters. Near vision was assessed binocularly using the N notation chart at a fixed distance of 40 cm for each individual. Torchlight examination and distance direct ophthalmoscopy was done. VI was defined as presenting visual acuity worse than 6/12 in the better eye. URE was defined as presenting visual acuity worse than 6/12 and improving to 6/12 or better on using a pinhole. Near Vision Impairment was defined as binocular presenting near vision worse than N8 among those age 35 years and older.

RESULTS

In total, 4057 were examined (84.5% response rate). The prevalence of VI was 3.52% (95% CI:2.89-4.13; n = 143). The prevalence of URE in the better eye was 1.95% (95% CI:1.54-2.42; n = 79). The Refractive Error Coverage and Effective Refractive Error Coverage were 34.8% and 31.3% respectively. The prevalence of NVI was 34.24% (95% CI: 32.1-36.40; n = 666).

CONCLUSION

The prevalence of VI and  URE was low, attributed to the availability and uptake of services in Koshi province in Nepal.

Cross-sectional study of prevalence, causes and trends in visual impairment in Nirmal District, Telangana, India: Nirmal Eye Evaluation for Trends study

OBJECTIVE

To determine the prevalence, causes and risk factors associated with visual impairment (VI) in the Nirmal district of Telangana, India, using extended Rapid Assessment of Visual Impairment (RAVI) methodology.

DESIGN

Cross-sectional study.

SETTING

Community setting.

PARTICIPANTS

Participants aged ≥16 years were enumerated from 90 randomly selected clusters and 4629/5400 (85.7%) participants were examined. Presenting visual acuity (VA) was assessed using a Snellen chart with E optotypes at a 6 m distance. Near vision was assessed binocularly using an N notation chart with tumbling E optotypes at a 40 cm distance. An anterior segment examination done followed by distance direct ophthalmoscopy at 50 cm. Non-mydriatic fundus images were obtained. VI was defined as presenting VA worse than 6/12 in the better eye. The prevalence of VI in the current study was compared with a RAVI study conducted in 2014 to assess the trends in VI among those aged ≥40 years.

PRIMARY OUTCOME

Prevalence, causes and risk factors for VI.

RESULTS

Among those examined, 55% were women, 53% had at least school-level education, 2.3% self-reported diabetes and 8.7% self-reported hypertension. The prevalence of VI was 8.81% (95% CI 8.01% to 9.67%). Overall, uncorrected refractive errors (49.5%) were the leading cause of VI, followed by cataracts (40.2%) and posterior segment diseases (4.9%). Among those aged ≥40 years, the prevalence of VI declined by 19.3% compared with the 2014 baseline study (from 20.2% to 16.3%; p<0.01).

CONCLUSION

The extended RAVI study conducted in the Nirmal district showed a considerable decline in the prevalence of VI. Targeted interventions are needed to provide adequate eye care for the high-risk groups in this district.

Effective Cataract Surgical Coverage in Four Large Districts in Telangana, India - Results from Rapid Assessment of Visual Impairment Study

PURPOSE

To report cataract surgical coverage (CSC) and effective Cataract Surgical Coverage (eCSC) from four districts in Telangana, India.

METHODS

Individuals aged ≥40 years were recruited from Adilabad, Mahbubnagar, Warangal and Khammam districts using two stage cluster sampling methodology. All participants had detailed eye examinations including visual acuity assessment using a standard Snellen chart at a distance of six meters, anterior segment examination and fundus imaging by trained professionals. CSC and eCSC were calculated for persons using a 6/12 visual acuity cut-off.

RESULTS

Of 12,150 individuals enumerated from four districts 11,238 (92.5%) were examined. The mean (standard deviation) age of the participants was 54.1 (±11.2) years (range: 40 to 102 years) and 54.6% (n = 6137) were women. Overall, the CSC (%) was 54.2%. It ranged from a highest of 59% in Khammam followed by 57.5% in Adilabad, 51.7% in Warangal, and a least of 49.7% in Mahbubnagar district. Overall, the eCSC (%) was 39.9%. It ranged from a highest of 46.1% in Adilabad followed by 43.2% in Khammam, 36.2% in Warangal district and a least of 35.8% in the Mahbubnagar district.

CONCLUSIONS

CSC and eCSC varied across the districts. A significant gap between CSC and eCSC is noted suggestive of challenges with quality of services. District-wise planning of cataract surgical services with a focus on quality care is recommended to improve coverage and contribute towards achieving the goal of universal eye health coverage in the Telangana State in India.

Methods for a population-based Comprehensive Eye care Workload Assessment (CEWA) study in Southern India

Eye care programs, in developing countries, are often planned using the prevalence of blindness and visual impairment, often estimated from Rapid Assessment of Avoidable Blindness (RAAB) surveys. A limitation of this planning approach is that it ignores the annual overall eye care requirements for a given population. Moreover, targets set are arbitrary, often influenced by capacity rather than need. To address this lacunae, we implemented a novel study design to estimate the annual need for comprehensive eye care in a 1.2 million populations. We conducted a population-based longitudinal study in Theni district, Tamil Nadu, India. All permanent residents of all ages were included. We conducted the study in three phases, (i) household-level enumeration and enrollment, (ii) basic eye examination (BEE) at household one-year post-enrollment, and (iii) assessment of eye care utilization and full eye examination (FEE) at central locations. All people aged 40 years and above were invited to the FEE. Those aged <40 years were invited to the FEE if indicated. In the main study, we enrolled 24,327 subjects (58% aged below 40 years and 42% aged 40 years and above). Of those less than 40 years, 72% completed the BEE, of whom 20% were referred for FEE at central location. Of the people aged ≥40 years, 70% underwent FEE. Our study design provides insights for appropriate long-term public health intervention planning, resource allocation, effective service delivery, and designing of eye care services for resource-limited settings.

Blindness and visual impairment and their causes in India: Results of a nationally representative survey

Introduction

Avoidable blindness is a significant public health problem in India. Nationally representative RAAB surveys (Rapid Assessment of Avoidable Blindness) are being conducted periodically in the country to know the current status of blindness in the country. The current study describes the findings from the RAAB survey conducted during 2015–19 in India.

Methodology

A cross-sectional, population-based survey was conducted across the entire country among persons aged 50 years and above using RAAB version 6 methodology. Presenting and pinhole visual acuity was recorded followed by lens examination using a torchlight. In order to estimate the prevalence of blindness and visual impairment in overall population in India, district weights were assigned to each of the 31 surveyed districts and the prevalence was standardized using the RAAB software.

Results

The overall weighted, age-gender standardized, prevalence of blindness (presenting visual acuity <3/60 in better eye) in population aged ≥50 years was 1.99% (95% CI 1.94%, 2.13%) and of visual impairment (VI) (presenting visual acuity <6/12 in better eye) was 26.68% (95% CI 26.57–27.17%). On multivariate analysis, adjusted odds ratio showed that blindness was associated with age ≥ 80 years (OR = 20.3, 95% CI: 15.6–26.4) and being illiterate (OR = 5.6, 95% CI: 3.6–8.9). Blindness was not found to be significantly associated with either gender or locality.

Conclusion

The results of the survey demonstrate that currently more than one fourth of persons aged 50 years and above are visually impaired (PVA<6/12 in better eye) in India. The prevalence of blindness among them is 1.99%, and older age and illiteracy are significantly associated with blindness. Major causes of blindness included cataract (66.2%), corneal opacity (CO) (8.2%), cataract surgical complications (7.2%), posterior segment disorders (5.9%) and glaucoma (5.5%). The proportion of blindness and visual impairment that is due to avoidable causes include 92.9% and 97.4% respectively.

Rapid assessment of prevalence of blindness and cataract surgery in Kabul province, Afghanistan

Objective

To estimate prevalence and causes of blindness and vision impairment and assess cataract surgical coverage and quality of cataract surgery in Kabul.

Methods and analysis

A total of 3751 adults aged 50 years and above were recruited from 77 randomly selected clusters. Each participant underwent presenting and pinhole visual acuity assessment and lens examination. Those with pinhole visual acuity <6/12 in either eye had a dilated fundus examination to determine the cause of reduced vision. Those with apparent lens opacity were interviewed on barriers to cataract surgery.

Results

The age-adjusted and sex-adjusted prevalence of blindness was 2.4% (95% CI: 1.8% to 3.0%). Prevalence of severe, moderate and mild vision impairment was 2.2% (95% CI: 1.7% to 2.7%), 6.9% (95% CI: 6.0% to 7.9%) and 8.7% (95% CI: 7.5% to 9.8%), respectively. Cataract was the main cause of blindness (36.8%), severe (54.4%) and moderate (46.1%) vision impairment. Uncorrected refractive error was the leading cause of mild vision impairment (20.3%). Age-related macular degeneration was the second leading cause of blindness (23.0%). In people with a presenting visual acuity of <3/60, cataract surgical coverage was 89.7%, and effective cataract surgical coverage was 67.8%. The major barriers to uptake of the available cataract surgical services were the need for surgery was not felt (23.7%) and cost (22.0%).

Conclusion

Kabul province has a high prevalence of blindness, largely due to cataract and age-related macular generation. The quality of cataract surgery is also lagging in terms of good visual outcomes. This calls for immediate efforts to improving the reach and quality of existing eye services and readiness to respond to the increasing burden of posterior eye disease.

Changes in Eye Health and Service Coverage in Nampula, Mozambique between 2011 and 2018

Purpose: Globally, there are few examples of repeated eye health surveys to assess changes in prevalence and causes of visual impairment, and service coverage over time. Two separate, unlinked rapid assessments of avoidable blindness (RAAB) were conducted in Nampula province, Mozambique in 2011 and 2018. This paper reports the observed changes and examines how the trends differ for males and females.Methods: Standard RAAB methodology was used in both studies. Two-stage cluster sampling was used to generate random samples of adults aged over 50 years. Participants underwent a simplified visual acuity (VA) exam, a lens exam and posterior segment exam using a direct ophthalmoscope for all subjects with presenting VA<6/18. Data were analysed using Stata and logistic regression models were developed to assess changes.Results: The 2011 study enrolled 3,050 people and examined 96.9% (2,954 people). The 2018 survey enrolled 4,191 people and examined 95.8% (4,015 people). Age- and sex-adjusted estimates of blindness decreased from 6.2% in 2011 to 4.5% in 2018 (z = -2.21, p = .028). Cataract surgical coverage was higher among males in both surveys (13.4% among males vs 7.7% among females in 2011, and 40.0% among males vs 19.4% among females in 2018) and the gender disparity grew between surveys.Conclusion: Significant changes were observed in the eye health and service coverage between 2011 and 2018. Further improvements to services are required to improve access for women and people with moderate visual impairment.

Prevalence of disabilities and non-communicable diseases in an elderly population in the Telangana state, India: a population-based cross-sectional study

OBJECTIVES

To assess the prevalence of disabilities (vision, hearing, mobility, cognitive, self-care and communication) and non-communicable diseases (NCDs) among the elderly population in two districts in Telangana, India.

DESIGN

Population-based cross-sectional study using a cluster random sampling method to select the study clusters.

SETTING

Elderly population in Khammam and Warangal districts were recruited. Detailed interviews were conducted by trained community health workers. Personal and demographic information such as age, gender, level of education and a self-report of NCDs was collected. The Washington Disability Questionnaire was administered to assess the presence of disabilities.

PARTICIPANTS

1821 participants aged ≥60 years, 54.5% were women, and 73.3% had no education.

PRIMARY OUTCOME MEASURE

Prevalence of disabilities and NCDs.

RESULTS

Overall, the prevalence of at least disability was 20.3% (95% CI 16.3 to 24.9). The prevalence of self- reported disabilities were: seeing (5.9%; 95% CI 4.4 to 7.8), mobility (12.8%; 95% CI 9.7 to 16.8), hearing (3.6%; 95% CI 2.7 to 4.8), cognition (4.8%; 95% CI 3.5 to 6.7), self-care (3.3%; 95% CI 2.3 to 4.7) and communication (1.8%; 95% CI 1.2 to 2.6). Overall, the prevalence of at least one NCD was 34.2% (95% CI 30.9 to 37.7). Hypertension was the most common systemic condition (25.4%; 95% CI 22.4 to 28.7), followed by diabetes (9.0%; 95% CI 7.3 to 11.0), and body pains (muscle-skeletal) (9.9%; 95% CI 8.1 to 12.2).

CONCLUSION

Every fifth elderly person in the districts of Khammam and Warangal in Telangana had at least one self-reported disability. Besides, a third of the elderly had at least one NCD. There is a definite need to develop comprehensive public health strategies to address disabilities and NCDs in Telangana.

Comprehensive eye care - Issues, challenges, and way forward

As we move from a disease-specific care model toward comprehensive eye care (CEC), there is a need for a more holistic and integrated approach involving the health system. It should encompass not only treatment, but also prevention, promotion, and rehabilitation of incurable blindness. Although a few models already exist, the majority of health systems still face the challenges in the implementation of CEC, mainly due to political, economic, and logistic barriers. Shortage of eye care human resources, lack of educational skills, paucity of funds, limited access to instrumentation and treatment modalities, poor outreach, lack of transportation, and fear of surgery represent the major barriers to its large-scale diffusion. In most low- and middle-income countries, primary eye care services are defective and are inadequately integrated into primary health care and national health systems. Social, economic, and demographic factors such as age, gender, place of residence, personal incomes, ethnicity, political status, and health status also reduce the potential of success of any intervention. This article highlights these issues and demonstrates the way forward to address them by strengthening the health system as well as leveraging technological innovations to facilitate further care.

Rationale for a Rapid Methodology to Assess the Prevalence of Hearing Loss in Population-Based Surveys

Data on the prevalence and causes of hearing loss is lacking from many low and middle-income countries, in part, because all-age population-based surveys of hearing loss can be expensive and time consuming. Restricting samples to older adults would reduce the sample size required, as hearing loss is more prevalent in this group. Population-based surveys of hearing loss require clinicians to be involved in the data collection team and reducing the duration of the survey may help to minimise the impact on service delivery. The objective of this paper was to identify the optimal age-group for conduct of population-based surveys of hearing loss, balancing sample size efficiencies, and expected response rates with ability to make inferences to the all-age population. Methods: Between 2013–2014, two all aged population-based surveys of hearing loss were conducted in one district each of India and Cameroon. Secondary data analysis was conducted to determine the proportion of hearing loss (moderate or greater) in people aged 30+, 40+ and 50+. Poisson regression models were developed to predict the expected prevalence of hearing loss in the whole population, based on the prevalence in people aged 30+, 40+, and 50+, which was compared to the observed prevalence. The distribution of causes in these age groups was also compared to the all-age population. Sample sizes and response rates were estimated to assess which age cut-off is most rapid. Results: Of 160 people in India and 131 in Cameroon with moderate or greater hearing loss, over 70% were older than 50 in both settings. For people aged 30+ (90.6% India; 76.3% Cameroon), 40+ (81% India; 75% Cameroon) and 50+ (73% India; 73% Cameroon) the proportions were higher. Prediction based on Poisson distributed observations the predicted prevalence based on those aged 30+, 40+, and 50+ fell within the confidence intervals of the observed prevalence. The distribution of probable causes of hearing loss in the older age groups was statistically similar to the total population. Sample size calculations and an analysis of response rates suggested that a focus on those aged 50+ would minimise costs the most by reducing the survey duration. Conclusion: Restricting the age group included in surveys of hearing loss, in particular to people aged 50+, would still allow inferences to be made to the total population, and would mean that the required sample size would be smaller, thus reducing the duration of the survey and costs.

Temporal trends in the prevalence and causes of visual impairment in the South Indian state of Telangana: a population-based cross-sectional study

OBJECTIVES

To investigate the temporal trends in the prevalence and causes of visual impairment (VI) in South India.

DESIGN

Population-based cross-sectional studies conducted during the years 2011-2012 and 2017 using identical study methods and in geographical locations are compared. The L V Prasad Eye Institute established services in Khammam and not in Warangal district after the 2011-2012 study.

SETTING

Khammam and Warangal districts in Telangana, India.

PARTICIPANTS

In total, 5357 participants aged ≥40 years were examined from two districts in the 2011-2012 study and 4923 participants were examined in the 2017 study.

MAIN OUTCOME MEASURES

Age-adjusted and gender-adjusted temporal trends in the prevalence and causes of VI.Blindness and moderate VI (MVI) were defined as presenting visual acuity worse than 6/60 and 6/18-6/60 in the better eye, respectively. VI included MVI and blindness.

RESULTS

Nearly 2500 participants were examined in each location in both the 2011-2012 and 2017 studies. In Khammam district, overall VI declined by 2.5% from 15.5% to 13.0% (p<0.001). While there was no significant change in MVI (p=0.566), blindness declined by 3.0% from 5.4% to 2.4% (p<0.001). In Warangal district, the overall VI remained unchanged (p=0.60). While MVI increased by 3% from 9.3% to 12.3% (p=0.001), blindness declined by 3.5% from 6.5% to 3.0% (p<0.001). While MVI due to cataract increased in both districts, there was a significant decline in MVI due to refractive errors in Khammam.

CONCLUSION

There was a significant decline in VI in Khammam district but not in Warangal district. The differential trends in prevalence and causes of VI can be explained by the availability and uptake of eye care services in these two districts.

Universal eye health in Odisha, India, Sunetra. Report # 1. Program planning

PURPOSE

To describe the program planning of Sunetra (Healthy Eyes), the universal eye health coverage in the Indian state Odisha.

METHODS

The Indian state of Odisha launched the universal eye health coverage in October 2017. This is the first Indian state to officially respond to the World Health Organization's Global Action Plan.

RESULTS

The Government of Odisha pledged INR 6,820 million (US$ 100 million approximately) spread over 5 years. Each third of the pledged money is allocated for immediate direct benefit, building the infrastructure and human resources, and creating a digital eye health platform for uniform documentation and policy planning.

CONCLUSION

It is hoped that at the end of 5 years, by 2022, the state will attain the goals prescribed in the Global Action Plan in eye care.

Prevalence and causes of visual impairment among adults aged 15-49 years in a rural area of north India - A population-based study

Purpose:

Very few studies have been conducted in India and other parts of the world on visual impairment among individuals aged 15–49 years. This study was conducted to determine the prevalence, causes, and associated factors of visual impairment among adults aged 15–49 years in a rural population of Jhajjar district, Haryana, north India.

Methods:

A population-based cross-sectional study was conducted in two blocks of Jhajjar district. A total of 34 villages were selected using probability proportionate to size sampling method. Adults aged 15–49 years were selected using compact segment cluster sampling approach. As part of the house-to-house survey, presenting visual acuity using screening chart corresponding to five “E” 6/12 optotypes was measured along with collection of other demographic details. The optometrists performed detailed eye assessment including repeat measurement of visual acuity using retro-illuminated conventional logMAR tumbling “E” charts, torch light examination, and non-cycloplegic refraction at a clinic site within the village to ascertain visual impairment and its cause.

Results:

Of 5,470 enumerated adults, 5,117 (94%) completed all study procedures. The age- and sex-adjusted prevalence of visual impairment was found to be 1.85% [95% confidence interval (CI): 1.48, 2.23] and blindness was 0.09% (95% CI: 0.01, 0.18). The age- and sex-adjusted prevalence of unilateral visual impairment was 1.11% (95% CI: 0.81, 1.41). Uncorrected refractive errors (84%) contributed maximum to visual impairment in this age group. The visual impairment in study participants was found to be associated with age and educational status.

Conclusion:

At the community level, uncorrected refractive errors contribute largely to visual impairment in the age group of 15–49 years.

Rapid assessment of avoidable blindness in Papua New Guinea: a nationwide survey

Objective

To estimate the prevalence and main causes of blindness and vision impairment in people aged 50 years and older in Papua New Guinea (PNG).

Design

National cross-sectional population-based survey in National Capital District (NCD), Highlands, Coastal and Islands regions.

Methods

Adults aged 50 years and above were recruited from 100 randomly selected clusters. Each participant underwent monocular presenting and pinhole visual acuity (VA) assessment and lens examination. Those with pinhole VA<6/12 in either eye had a dilated fundus examination to determine the primary cause of reduced vision. Those with obvious lens opacity were interviewed on barriers to cataract surgery.

Results

A total of 4818 adults were examined. The age-adjusted and sex-adjusted prevalence of blindness (VA <3/60), severe vision impairment (SVI, VA <6/60 but ≥3/60), moderate vision impairment (MVI, VA <6/18 but ≥6/60) and early vision impairment (EVI, VA <6/12 but ≥6/18) was 5.6% (95% CI 4.9% to 6.3%), 2.9% (95% CI 2.5% to 3.4%), 10.9% (95% CI 9.9% to 11.9%) and 7.3% (95% CI 6.6% to 8.0%), respectively. The main cause of blindness, SVI and MVI was cataract, while uncorrected refractive error was the main cause of EVI. A significantly higher prevalence of blindness, SVI and MVI occurred in the Highlands compared with NCD. Across all regions, women had lower cataract surgical coverage and spectacle coverage than men.

Conclusions

PNG has one of the highest reported prevalence of blindness globally. Cataract and uncorrected refractive error are the main causes, suggesting a need for increased accessible services with improved resources and advocacy for enhancing eye health literacy.

Magnitude and Determinants of the Ratio between Prevalence of Low Vision and Blindness in Rapid Assessment of Avoidable Blindness Surveys

PURPOSE

To determine the magnitude and determinants of the ratio between prevalence of low vision and prevalence of blindness in rapid assessment of avoidable blindness (RAAB) surveys globally.

METHODS

Standard RAAB reports were downloaded from the repository or requested from principal investigators. Potential predictor variables included prevalence of uncorrected refractive error (URE) as well as gross domestic product (GDP) per capita, health expenditure per capita of the country across World Bank regions. Univariate and multivariate linear regression were used to investigate the correlation between potential predictor variables and the ratio.

RESULTS

The results of 94 surveys from 43 countries showed that the ratio ranged from 1.35 in Mozambique to 11.03 in India with a median value of 3.90 (Interquartile range 3.06;5.38). Univariate regression analysis showed that prevalence of URE (p = 0.04), logarithm of GDP per capita (p = 0.01) and logarithm of health expenditure per capita (p = 0.03) were significantly associated with the higher ratio. However, only prevalence of URE was found to be significant in multivariate regression analysis (p = 0.03).

CONCLUSION

There is a wide variation in the ratio of the prevalence of low vision to the prevalence of blindness. Eye care service utilization indicators such as the prevalence of URE may explain some of the variation across the regions.

Rapid assessment of visual impairment in urban population of Delhi, India

Purpose

To determine the prevalence, causes and associated demographic factors related to visual impairment amongst the urban population of New Delhi, India.

Methods

A population-based, cross-sectional study was conducted in East Delhi district using cluster random sampling methodology. This Rapid Assessment of Visual Impairment (RAVI) survey involved examination of all individuals aged 40 years and above in 24 randomly selected clusters of the district. Visual acuity (VA) assessment and comprehensive ocular examination were done during the door-to-door survey. A questionnaire was used to collect personal and demographic information of the study population. Blindness and Visual Impairment was defined as presenting VA <3/60and <6/18 in the better eye, respectively. Descriptive statistics were computed along with multivariable logistic regression analysis to determine associated factors for visual impairment.

Results

Of 2421 subjects enumerated, 2331 (96.3%) were available for ophthalmic examination. Among those examined, 49.3% were males. The prevalence of visual impairment (VI) in the study population, was 11.4% (95% C.I. 10.1, 12.7) and that of blindness was 1.2% (95% C.I. 0.8, 1.6). Uncorrected refractive error was the leading cause of VI accounting for 53.4% of all VI followed by cataract (33.8%). With multivariable logistic regression, the odds of having VI increased with age (OR= 24.6[95% C.I.: 14.9, 40.7]; p<0.001). Illiterate participants were more likely to have VI [OR= 1.5 (95% C.I.: 1.1,2.1)] when compared to educated participants.

Conclusions

The first implementation of the RAVI methodology in a North Indian population revealed that the burden of visual impairment is considerable in this region despite availability of adequate eye care facilities. Awareness generation and simple interventions like cataract surgery and provision of spectacles will help to eliminate the major causes of blindness and visual impairment in this region.

Changing trends in the prevalence of visual impairment, uncorrected refractive errors and use of spectacles in Mahbubnagar district in South India

Background/Aim:

The Andhra Pradesh Eye disease Study (APEDS) was a conventional cross-sectional study conducted in four locations during 1996-2000. Ten years later, a Rapid Assessment of Refractive Errors (RARE) survey was conducted in one of the geographical regions. The prevalence of visual impairment (VI), uncorrected refractive error (URE), spectacles use obtained from both the surveys was compared.

Settings and Design:

Rural settings; cross-sectional studies.

Materials and Methods:

In both the surveys, distance visual acuity (VA) was assessed using a logMAR chart. Pinhole VA was assessed if presenting VA was <20/20 in APEDS and <20/40 in RARE. VI was defined as presenting VA <20/40 in the better eye. URE was defined as presenting VA <20/40 and improving to ≥20/40 with a pinhole.

Statistical Analysis Used:

Performed using Statistical Package for Social Sciences (SPSS). Chi square tests and t-test were used.

Results and Conclusions:

The results from a RARE survey with 3,095 subjects were compared with an APEDS dataset that had 1,232 subjects in the same age group of 15-49 years. The prevalence of VI has decreased from 9.5% (95% CI, 7.7-11.1) in APEDS to 2.7% (95% CI, 2.1-3.3) in RARE. Similarly, the prevalence of URE in the better eye decreased from 5.8% (95% CI, 4.5-7.1) to 2.3% (95% CI, 1.8-2.8). The usage of spectacles increased from 6.6% (95% CI, 5.2-8.0) to 9.7% (95% CI, 8.7-10.7). There is a decreasing trend in the prevalence of VI and URE in Mahbubnagar district in Andhra Pradesh over a decade.

Population-based assessment of sensitivity and specificity of a pinhole for detection of significant refractive errors in the community

BACKGROUND

Measurements of refractive errors through subjective or automated refraction are not always possible in rapid assessment studies and community vision screening programs; however, measurements of vision with habitual correction and with a pinhole can easily be made. Although improvements in vision with a pinhole are assumed to mean that a refractive error is present, no studies have investigated the magnitude of improvement in vision with pinhole that is predictive of refractive error. The aim was to measure the sensitivity and specificity of 'vision improvement with pinhole' in predicting the presence of refractive error in a community setting.

METHODS

Vision and vision with pinhole were measured using a logMAR chart for 488 of 582 individuals aged 15 to 50 years. Refractive errors were measured using non-cycloplegic autorefraction and subjective refraction. The presence of refractive error was defined using spherical equivalent refraction (SER) at two levels: SER greater than ± 0.50 D sphere (DS) and SER greater than ±1.00 DS. Three definitions for significant improvement in vision with a pinhole were used: 1. Presenting vision less than 6/12 and improving to 6/12 or better, 2. Improvement in vision of more than one logMAR line and 3. Improvement in vision of more than two logMAR lines.

RESULTS

For refractive error defined as spherical equivalent refraction greater than ± 0.50 DS, the sensitivities and specificities for the pinhole test predicting the presence of refractive error were 83.9 per cent (95% CI: 74.5 to 90.9) and 98.8 per cent (95% CI: 97.1 to 99.6), respectively for definition 1. Definition 2 had a sensitivity 89.7 per cent (95% CI: 81.3 to 95.2) and specificity 88.0 per cent (95% CI: 4.4 to 91.0). Definition 3 had a sensitivity of 75.9 per cent (95% CI: 65.5 to 84.4) and specificity of 97.8 per cent (95% CI: 95.8 to 99.0). Similar results were found with spherical equivalent refraction greater than ±1.00 DS, when tested against the three pinhole-based definitions.

CONCLUSION

Refractive error definitions based on improvement in vision with the pinhole shows good sensitivity and specificity at predicting the presence of significant refractive errors. These definitions can be used in rapid assessment surveys and community-based vision screenings.

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.