Screening efficacy of a simplified logMAR chart

Background: Snellen acuity charts are the most commonly used method for visual acuity (VA) testing in screening programmes despite comparative studies verifying that the logarithm of minimum angle of resolution (logMAR) acuity measurement charts are more accurate than the Snellen chart acuity measurements. LogMAR acuity measurement charts however are not well implemented in routine clinical practice because of the increased testing time and the complexity of scoring. To implement the logMAR method in a screening programme, there has to be some simplification of it. Aim: This study evaluates the efficacy of a simplified logMAR chart, designed for VA testing over the conventional Snellen chart, in a school-based vision-screening programme. Methods: We designed a simplified logMAR chart by employing the principles of the Early Treatment Diabetic Retinopathy Study (ETDRS) chart in terms of logarithmic letter size progression, inter-letter spacing, and inter-line spacing. Once the simplified logMAR chart was validated by students in the Elite school vision-screening programme, we set out to test the chart in 88 primary and middle schools in the Tiruporur block of Kancheepuram district in Tamil Nadu. One school teacher in each school was trained to screen a cross-sectional population of 10 354 primary and secondary school children (girls: 5488; boys: 4866) for VA deficits using a new, simplified logMAR algorithm. An experienced paediatric optometrist was recruited to validate the screening methods and technique used by the teachers to collect the data. Results: The optometrist screened a subset of 1300 school children from the total sample. The optometrist provided the professional insights needed to validate the clinical efficacy of the simplified logMAR algorithm and verified the reliability of the data collected by the teachers. The mean age of children sampled for validation was 8.6 years (range: 9–14 years). The sensitivity and the specificity of the simplified logMAR chart when compared to the standard logMAR chart were found to be 95% and 98%, respectively. Kappa value was 0.97. Sensitivity of the teachers’ screening was 66.63% (95% confidence interval [CI]: 52.73–77.02) and the specificity was 98.33% (95% CI: 97.49–98.95). Testing of VA was done under substandard illumination levels in 87% of the population. A total of 10 354 children were screened, 425 of whom were found to have some form of visual and/or ocular defect that was identified by the teacher or optometrist. Conclusion: The simplified logMAR testing algorithm proved to be less time consuming than the standard logMAR test. This suggests that the simplified logMAR chart is effective in vision-screening programmes and would be a reliable alternative to the standard logMAR chart and therefore replace the use of Snellen chart acuity tests in vision-screening programmes. The study also showed that non-healthcare providers, such as teachers, can reliably administer the simplified logMAR test. Keywords: vision screening; school children; vision screening standards; screening reliabilit

The prevalence of self-reported vision difficulty in economically disadvantaged regions of South Africa

Background: Vision impairment, resulting in vision difficulties, is a leading cause of disability, and hence one of the key barriers for people to access education and employment, which may force them into poverty. Objectives: The objective of this study was to determine the prevalence of self-reported vision difficulties as an indicator of vision impairment in economically disadvantaged regions in South Africa, and to examine the relationship between self-reported vision difficulties and socio-economic markers of poverty, namely, income, education and health service needs. Methods: A cross-sectional study was conducted in economically disadvantaged districts to collect data from households on poverty and health, including vision difficulty. As visual acuity measurements were not conducted, the researchers used the term vision difficulty as an indicator of vision impairment. Data were collected from 27 districts (74 901 respondents). Logistic regression analysis and chi-square tests were used to determine bivariate relationships between variables and self-reported vision difficulty. Kernel density estimators were used for age, categorised by self-reported and not reported vision difficulty. Results: Prevalence of self-reported vision difficulty was 11.2% (95% CI, 8.7% – 13.7%). More women (12.7%) compared to men (9.5%) self-reported vision difficulty (p < 0.01). Self-reported vision difficulty was higher (14.2%) for respondents that do not spend any money. A statistically significant relationship was found between the highest level of education and self-reporting of vision difficulty; as completed highest level of education increased, self-reporting of vision difficulty became lower (p < 0.01). A significantly higher prevalence of self-reported vision difficulty was found in respondents who are employed (p < 0.01), 17% (95% CI: 12.8% – 21.1%). Conclusion: The evidence from this study suggests associations between socio-economic factors and vision difficulties that have a two-fold relationship (some factors such as education, and access to eye health services are associated with vision difficulty whilst vision difficulty may trap people in their current poverty or deepen their poverty status). The results are thus indicative of the need for further research in South Africa

Trends and implications for achieving VISION 2020 human resources for eye health targets in 16 countries of sub-Saharan Africa by the year 2020

BACKGROUND: Development of human resources for eye health (HReH) is a major global eye health strategy to reduce the prevalence of avoidable visual impairment by the year 2020. Building on our previous analysis of current progress towards key HReH indicators and cataract surgery rates (CSRs), we predicted future indicator achievement among 16 countries of sub-Saharan Africa by 2020. METHODS: Surgical and HReH data were collected from national eye care programme coordinators on six practitioner cadres: ophthalmologists, cataract surgeons, ophthalmic clinical officers, ophthalmic nurses, optometrists and 'mid-level refractionists' and combined them with publicly available population data to calculate practitioner-to-population ratios and CSRs. Data on workforce entry and exit (2008 to 2010) was used to project practitioner population and CSR growth between 2011 and 2020 in relation to projected growth in the general population. Associations between indicator progress and the presence of a non-physician cataract surgeon cadre were also explored using Wilcoxon rank sum tests and Spearman rank correlations. RESULTS: In our 16-country sample, practitioner per million population ratios are predicted to increase slightly for surgeons (ophthalmologists/cataract surgeons, from 3.1 in 2011 to 3.4 in 2020) and ophthalmic nurses/clinical officers (5.8 to 6.8) but remain low for refractionists (including optometrists, at 3.6 in 2011 and 2020). Among countries that have not already achieved target indicators, however, practitioner growth will be insufficient for any additional countries to reach the surgeon and refractionist targets by year 2020. Without further strategy change and investment, even after 2020, surgeon growth is only expected to sufficiently outpace general population growth to reach the target in one country. For nurses, two additional countries will achieve the target while one will fall below it. In 2011, high surgeon practitioner ratios were associated with high CSR, regardless of the type of surgeon employed. The cataract surgeon workforce is growing proportionately faster than the ophthalmologist. CONCLUSIONS: The HReH workforce is not growing fast enough to achieve global eye health targets in most of the sub-Saharan countries we surveyed by 2020. Countries seeking to make rapid progress to improve CSR could prioritise investment in training new cataract surgeons over ophthalmologists and improving surgical output efficiency

Uncorrected refractive errors

Global estimates indicate that more than 2.3 billion people in the world suffer from poor vision due to refractive error; of which 670 million people are considered visually impaired because they do not have access to corrective treatment. Refractive errors, if uncorrected, results in an impaired quality of life for millions of people worldwide, irrespective of their age, sex and ethnicity. Over the past decade, a series of studies using a survey methodology, referred to as Refractive Error Study in Children (RESC), were performed in populations with different ethnic origins and cultural settings. These studies confirmed that the prevalence of uncorrected refractive errors is considerably high for children in low-and-middle-income countries. Furthermore, uncorrected refractive error has been noted to have extensive social and economic impacts, such as limiting educational and employment opportunities of economically active persons, healthy individuals and communities. The key public health challenges presented by uncorrected refractive errors, the leading cause of vision impairment across the world, require urgent attention. To address these issues, it is critical to focus on the development of human resources and sustainable methods of service delivery. This paper discusses three core pillars to addressing the challenges posed by uncorrected refractive errors: Human Resource (HR) Development, Service Development and Social Entrepreneurship

Mapping human resources for eye health in 21 countries of sub-Saharan Africa: current progress towards VISION 2020.

BACKGROUND: Development of human resources for eye health (HReH) is a major focus of the Global Action Plan 2014 to 2019 to reduce the prevalence of avoidable visual impairment by 25% by the year 2019. The eye health workforce is thought to be much smaller in sub-Saharan Africa than in other regions of the world but data to support this for policy-making is scarce. We collected HReH and cataract surgeries data from 21 countries in sub-Sahara to estimate progress towards key suggested population-based VISION 2020 HReH indicators and cataract surgery rates (CSR) in 2011. METHODS: Routinely collected data on practitioner and surgery numbers in 2011 was requested from national eye care coordinators via electronic questionnaires. Telephone and e-mail discussions were used to determine data collection strategies that fit the national context and to verify reported data quality. Information was collected on six practitioner cadres: ophthalmologists, cataract surgeons, ophthalmic clinical officers, ophthalmic nurses, optometrists and 'mid-level refractionists' and combined with publicly available population data to calculate practitioner to population ratios and CSRs. Associations with development characteristics were conducted using Wilcoxon rank sum tests and Spearman rank correlations. RESULTS: HReH data was not easily available. A minority of countries had achieved the suggested VISION 2020 targets in 2011; five countries for ophthalmologists/cataract surgeons, four for ophthalmic nurses/clinical officers and two for CSR. All countries were below target for optometrists, even when other cadres who perform refractions as a primary duty were considered. The regional (sample) ratio for surgeons (ophthalmologists and cataract surgeons) was 2.9 per million population, 5.5 for ophthalmic clinical officers and nurses, 3.7 for optometrists and other refractionists, and 515 for CSR. A positive correlation between GDP and CSR as well as many practitioner ratios was observed (CSR P = 0.0042, ophthalmologists P = 0.0034, cataract surgeons, ophthalmic nurses and optometrists 0.1 > P > 0.05). CONCLUSIONS: With only a minority of countries in our sample having reached suggested ophthalmic cadre targets and none having reached targets for refractionists in 2011, substantially more targeted investment in HReH may be needed for VISION 2020 aims to be achieved in sub-Saharan Africa

A population-based study of visual impairment in the Lower Tugela health district in KZN, SA

A cross-sectional, population-based, epidemiological study of blindness and visual impairment was conducted to evaluate the prevalence of vision loss and various sight-threatening conditions in the Lower Tugela health district of the KwaZulu-Natal province, South Africa. This study was conducted on a randomly selected sample of 3444 individuals from the district. This number represented 84% of those who were visited and 80.1% of the total sample selected. The participants ranged in age from 5 to 93 years (mean of 29.2 years and a median of 20.0 years). The proportion of men to women differed between participants aged 30 years. In both age groups, women represented the majority of participants (66.5%), but the number of women to men in the older age group was approximately twice that found in the group aged less than 30 years. The difference in age between the men and women in the study was not statistically significant (p >0.5). The study revealed that 6.4% of the population studied were visually impaired. The distribution of uncorrected visual acuity was better for women than for men for both OD and OS (p = 0.000 for OD and OS). The main causes of visual impairment were refractive error (44.5%), cataract (31.2%), glaucoma (6.0%), hypertensive retinopathy (4.1%) and diabetic retinopathy (4.1%). Unilateral blindness (OD) was present in 0.78% (95% Confidence interval (CI): 0.42%-1.14%) of participants and unilateral blindness (OS) was present in 1.1% (95% CI: 0.70%-1.50%). Thirty-one participants (0.9%) were bilaterally blind with the main causes being cataracts (54.8%) and refractive error (12.9%). Glaucoma and hypertensive retinopathy were responsible for 6.4% of ..bilateral blindness. Diabetic retinopathy, other retinal conditions (coloboma) and corneal scarring were each responsible for 3.2% of bilateral blindness. Albinism, coloboma and age-related macular degeneration accounted for 9.7% of bilateral blindness. The data provides much needed information to support the planning of eye care programs in KwaZulu-Natal

Adequacy and relevance of Indian optometry curricula to practicing optometrists

Context: To ensure that future optometry graduates receive appropriate knowledge and skills to provide comprehensive primary eye care, it is important to evaluate the current optometry curricula. Aim: To evaluate the relevance of optometry curriculum in India by assessing the perceptions on the curriculum strengths and lacunae by practicing optometrists. Setting and Design: Questionnaire-based survey in India. Materials and Methods: A questionnaire was used to elicit the opinions of purposively selected, 4-year trained optometrists, on the adequacy, and relevance of the optometric curriculum subjects offered in the optometric institutions. Statistical Analysis Used: Descriptive analysis was used to show reported frequencies of single responses to questions. The Cronbach's alpha test was used to measure consistency of responses to questions. Results: One hundred and three valid complete responses were received. Fifty eight (56%) participating optometrists were females. The most adequately covered optometry subjects as reported by the participating optometrists were contact lenses (n = 87, 85%), refraction (n = 86, 84%), ocular investigation (n = 75, 73%), and ocular disease (n = 75, 73%). Ocular diseases, low vision, and dispensing optics were, reportedly, covered sufficiently in theory, but the participants lacked adequate practical exposure. Basic optics had a maximum score regarding practical exposure, among support subjects while communication skills, computer skills, and community optometry were rated very low. Business aspect and legal aspect were inadequately taught. The optometry curricula in India are considered as being adequate and relevant, some subjects need more practical demonstrations and teaching of support subjects needs amendments

Near vision correction and quality of life among textile workers.

Background: Uncorrected near vision impairment affects the performance of near vision tasks and activities for an estimated 410 million people worldwide. Once normal vision becomes blurred or impaired, the ordinary and simple daily routines of individuals become difficult; often resulting in frustration and irritation, which is consequently reflected in their quality of life. Aim: We investigated the change of vision-related quality of life (VRQoL) following near correction among textile factory workers in South Africa. Methods: Presbyopic subjects who were 40 years and older with no other eye conditions were provided near spectacle correction. We interviewed subjects to ascertain their VRQoL scores using the National Eye Institute Visual Function Questionnaire, pre-treatment and 6 months after the provision of near corrections. Setting: The study was conducted among the textile factory workers in KwaZulu-Natal, South Africa. Results: A total of 423 textile factory workers were followed up from seven textile factories in Durban. The overall increase in VRQoL scores of 21.9 (95% CI 16.7–27) was significant (p < 0.01). This translates to a 36.5% (95% CI 30.6–42.4) change in VRQoL. The increase was highest among participants of African origin 25.1 (95% CI 21.14–29.1), males 18.8 (95% CI 12.6–27.2), among those who had completed primary school 35.8 (95% CI 21.7–49.9) and among participants with other responsibilities (ironing and quality assurance) 21.9 (95% CI 16.7–27). Conclusion: Correcting near vision impairment improved the VRQoL scores of textile factory workers. The results showed that VRQoL scores increased significantly across levels of education and categories of responsibilit

Near vision correction and work productivity among textile workers

Purpose: Uncorrected presbyopia (near vision impairment) is prevalent in approximately 517 million people worldwide; this prevalence ranges from 30% to 80% in Africa. Good near vision is needed for a range of tasks; therefore, uncorrected presbyopia can negatively affect the quality of life of individuals, impact families and society, and potentially have negative implications on employment and labour work productivity. This study aimed to determine the impact of near vision correction on the work productivity of clothing factory workers. Methods: We conducted a cross-sectional study and sampled all workers who were aged 40 years and older and who performed near vision tasks (e.g. machinist, cutter, zip sewer, clothing pressers and quality controllers) in seven clothing factories. We included workers who were employed for at least 3 months and whose uncorrected near visual acuity could be improved and corrected to better than 6/9 with spectacle correction. Workers were provided with near vision spectacles, and changes in their work productivity were evaluated after 6 months, using the factories’ output records as an indicator for measurement. Results: The final sample comprised 268 individuals, with 56% of African origin (n = 151) and 49% (n = 115) Indian origin. There were mainly females (94%) in the sample, and the average age was 48 years (± 5.5 years, range 40–62 years). The overall post-correction mean production score (70.5 [SD ± 19.9]) was significantly higher than the overall pre-correction mean production score (67.0 [SD ±20.3]) (p < 0.001). The average change in production score was 3.5 (95% confidence interval [CI] 2.7–4.3), and the percent difference was 6.4% (95% CI 5.2–7.7). The increase in work productivity was significant for individuals of African (p < 0.001) and Indian origins (p < 0.001) but not for those of mixed race (p = 0.364; n = 2). Post-correction, the production scores of women increased significantly by 6.6% (95% CI 5.3–7.9) (p < 0.001). Significant increases in production scores were recorded for machinists, clothing pressers and quality controllers. Conclusion: Significant changes in work productivity among the workers with presbyopic correction were recorded. The clothing industry served as a favourable setting to examine changes in work productivity, obtaining reliable scores of output. This study was used as an exploratory investigation, and the results will be used to inform a randomised-controlled study that will provide stronger validation for the hypothesis that near vision correction impacts work productivit