Situation analysis on the integration of refractive error services provided by optometrists into the national health services in Kenya.

INTRODUCTION: Even though the burden of uncorrected refractive error could potentially be addressed through innovative and cost-effective approaches, integration of the services into the National Health Services (NHS) is desirable. However, minimal information exists on the current situation warranting the need for evidence about the integration of refractive error service provided by optometrists into the national health services in Kenya. METHODS: A situation analysis of the Kenyan refractive error services provided by optometrists within the NHS was undertaken based on access to service delivery, service coverage, and human resource. A strengths, weaknesses, opportunities, and threats analysis was undertaken based on the existent evidence to identify the core factors that could potentially facilitate or hinder the integration of refractive error services provided by optometrists within the National Health Services. The proportion of optometrists to be integrated in the NHS was estimated based on the minimum ratios recommended by the World Health Organization. RESULTS: A section of tertiary and secondary healthcare facilities in Kenya have specific services to address refractive errors within the NHS with most facilities lacking such services. Treatment of refractive error occurs at the level of eye care general services. There are 11,547 health facilities offering primary care services in Kenya. However, none of them offers refractive error services and only a section of facilities offering county health referral services provides eye care services which is limited to refraction without provision of spectacles. The existing workforce comprises of ophthalmologists, optometrists and ophthalmic clinical officers, together with nurses and other general paramedical assistants. Optometrists, ophthalmologists and ophthalmic clinical officers are allowed to undertake refraction. However, optometrists majorly practices in the private sector. Centralization of eye care services in urban areas, weak referral systems, and a shortage in the workforce per population was observed. CONCLUSIONS: The Kenyan NHS should advocate for primary care and reorient the current hospital-based delivery approach for refractive error services. This is attributed to the fact that provision of refractive error services at primary care remains effective and efficient and could translate to early detection of other ocular conditions. The existing human resources in the eye health ecosystem in Kenya should maximize their efforts towards addressing uncorrected refractive error and optometrists should be integrated into the NHS.

Proposed task shifting integrated with telemedicine to address uncorrected refractive error in Kenya: Delphi study.

BACKGROUND: Developing countries such as Kenya still experience challenges around human resource to deliver refractive error services. However, given the burden of uncorrected refractive error, adoption of innovative and cost effective approaches is desirable. Hence this study intended to develop a task shifting framework integrated with telemedicine to potentially scale refractive error services. METHODS: This was an exploratory study conducted in four phases as follows: a scoping review of the scope of practice for ophthalmic workers in Kenya, an interview with key opinion leaders on the need for integration of public health approaches such as the vision corridors within the eye health ecosystem in Kenya and their knowledge on task shifting, and finally development and validation of a proposed task shifting framework through a Delphi technique. Purposive sampling was used to recruit key opinion leaders and data was collected via telephonic interviews. The qualitative data was analyzed thematically using NVivo Software, Version 11. RESULTS: The scoping review showed that only optometrists, ophthalmologists and ophthalmic clinical officers are allowed to undertake refraction in Kenya. All of the key opinion leaders (100%) were aware of task shifting and agreed that it is suitable for adoption within the eye health ecosystem in Kenya. All of the key opinion leaders (100%) agreed that skills development for healthcare workers without prior training on eye health supervised by optometrists through telemedicine is desirable. Notwithstanding, all of the key opinion leaders (100%) agreed that integration of public health approaches such as the vision corridors across all levels of healthcare delivery channels and development of a self-assessment visual acuity tool is desirable. Finally all of the key opinion leaders (100%) agreed that task shifting is relevant for adoption within the eye health ecosystem in Kenya. The developed framework prioritized partnership, advocacy, skills development, establishment and equipping of refraction points. The proposed framework advocated for a telemedicine between professionals with conventional training and those with skills development. CONCLUSION: Task shifting integrated with telemedicine could cost effectively scale refractive error service delivery. However, internal and external factors may hinder the success warranting the need for a multi-faceted interventions and a connection between planning and training to scale the uptake.

Distribution of anterior chamber angle measurements in South African young adults: an optical coherence tomography study.

PURPOSE: Assessment of anterior chamber angle (ACA) variables is important to screen, diagnose and monitor ocular anomalies. Even though data on ACA variables, such as angle-opening distance taken at 500 µm (AOD500) and trabecular-iris angle (TIA), are available in the literature, limited information is available about these variables in African sub-populations. The purpose of this study is to describe the distribution of ACA measurements (AOD500 and TIA) in a South African young adult population. METHODS: In this cross-sectional study, 700 young adults were recruited from a university student population using two-stage random sampling. The Optovue iVue 100 optical coherence tomographer was used to measure the ACA variables. The distribution of the AOD500 and TIA measurements was analysed using descriptive and inferential statistics. Data from only the right eyes were analysed because the ACA measurements in the two eyes showed high levels of interocular symmetry. RESULTS: The measurements for the nasal and temporal ACAs were asymmetrically distributed (p < 0.001). The median AOD500 measurements in the nasal and temporal angles were 539 µm and 542 µm, respectively. The median TIA measurements were similar (~ 36°) in the two horizontal angles. The temporal ACA measurements were slightly higher than the nasal ACA measurements. Females had higher median ACA measurements than males (p ≥ 0.029). CONCLUSION: The ACA measurements in South African young adults resemble non-Gaussian curves. The ACA measurements are different from that reported in other sub-populations worldwide and most participants had ACA measurements associated with non-occludable ACAs.

Refractive Error in a Sample of Black High School Children in South Africa.

SIGNIFICANCE: This study focused on a cohort that has not been studied and who currently have limited access to eye care services. The findings, while improving the understanding of the distribution of refractive errors, also enabled identification of children requiring intervention and provided a guide for future resource allocation. PURPOSE: The aim of conducting the study was to determine the prevalence and distribution of refractive error and its association with gender, age, and school grade level. METHODS: Using a multistage random cluster sampling, 1586 children, 632 males (40%) and 954 females (60%), were selected. Their ages ranged between 13 and 18 years with a mean of 15.81 ± 1.56 years. The visual functions evaluated included visual acuity using the logarithm of minimum angle of resolution chart and refractive error measured using the autorefractor and then refined subjectively. Axis astigmatism was presented in the vector method where positive values of J0 indicated with-the-rule astigmatism, negative values indicated against-the-rule astigmatism, whereas J45 represented oblique astigmatism. RESULTS: Overall, patients were myopic with a mean spherical power for right eye of -0.02 ± 0.47; mean astigmatic cylinder power was -0.09 ± 0.27 with mainly with-the-rule astigmatism (J0 = 0.01 ± 0.11). The prevalence estimates were as follows: myopia (at least -0.50) 7% (95% confidence interval [CI], 6 to 9%), hyperopia (at least 0.5) 5% (95% CI, 4 to 6%), astigmatism (at least -0.75 cylinder) 3% (95% CI, 2 to 4%), and anisometropia 3% (95% CI, 2 to 4%). There was no significant association between refractive error and any of the categories (gender, age, and grade levels). CONCLUSIONS: The prevalence of refractive error in the sample of high school children was relatively low. Myopia was the most prevalent, and findings on its association with age suggest that the prevalence of myopia may be stabilizing at late teenage years.

Factors associated with protective eyewear use among cocoa farmers in Ghana.

To determine the factors that are associated with the use of protective eyewear (PEW) among cocoa farmers in Ghana, a multistage random sample of 556 cocoa farmers were recruited from four districts in the country. A questionnaire was used to elicit information on the use of PEW and barriers to its use among these farmers. Only 34 (6.1%) participants reported using PEW. Being female, old age and perception of good distance vision was associated with lower odds of PEW use. However, higher educational attainment, application of fertiliser and pesticides were associated with higher odds of PEW use. Participants cited non-availability, unaffordability and ignorance/lack of training as the main barriers to the use of PEW. The low use of PEW could be addressed through ocular health education and occupational health and safety policy initiatives.

SWOT analysis of the models used by social enterprises in scaling effective refractive error coverage to achieve the 2030 in SIGHT in Kenya.

Uncorrected refractive error has predominantly been delivered through commercial entrepreneurship in Kenya. However, to achieve the 2030 IN SIGHT, integration of other forms of entrepreneurship such as the social entrepreneurship is desirable to supplement the efforts of the dominant commercial entrepreneurship. Therefore, this study intended to undertake a SWOT analysis of the current models used by social enterprises in scaling effective refractive error coverage to achieve the 2030 IN SIGHT in Kenya. A review of the seven national strategic plans for eye health in Kenya was undertaken to get a glimpse on the efforts directed towards uncorrected refractive error in achieving the 2030 IN SIGHT. The review was inclined towards assessing the efforts directed by the strategic plans towards scaling human resource, spectacle provision and refraction points. A SWOT analysis was undertaken based on the financial, impact and the approach report for each model. A key informant interview was conducted with a representative and three to five members of the social enterprise about the model. Thereafter, the modified SWOT analysis based on the review and the interview was presented to the representatives of the social enterprises. Purposive sampling was used to identify seven models used by social enterprises in the delivery of refractive error services in Kenya. Finally, the recommendations were presented to key opinion leaders for an input through a Delphi technique. Out of the seven national strategic plans for eye health reviewed, only the strategic plan 2020-2025 intends to establish optical units within 15 different counties in Kenya. Of the seven models currently utilized by social enterprises, only the Kenya Society for the Blind has integrated the telemedicine concept. On application of mHealth, all of the social enterprises models tend to embrace the approach for screening activities. None of the models has a strengthened referral pathway utilizing telereferral and telemedicine. Out of all the models, only Operation Eyesight Universal, Fred Hollow Foundation and Peek Acuity do not depend on sales of subsidized spectacles for sustainability. Every model has the capacity to propel the delivery of refractive error services depending on its comprehensiveness. However, for the 2030 IN SIGHT to be achieved, models prioritizing human resource through telemedicine integration, service provision across all sectors, awareness creation and enhancing cost efficiency are desirable.

Telemedicine integration into the eye health ecosystem in scaling of effective refractive error coverage in Kenya.

This study explored the potential of telemedicine integration into the eye health ecosystem with an aim of scaling effective refractive error coverage in Kenya. This exploratory study was conducted telephonically and through online interviews with key opinion leaders, ophthalmologists, optometrists, ophthalmic clinical officers, optical technicians and beneficiaries of the optical technician's services in rural areas. A telemedicine workflow was developed and validated based on the comments from the key opinion leaders using the Delphi technique. Quantitative and qualitative data were analysed using SPSS and NVivo Software respectively. All of the key opinion leaders agreed that telemedicine is relevant in the eye health ecosystem and recognition of primary vision technicians is critical for effective telemedicine integration. The reasons for the need of telemedicine integration were categorized into; good relationship, organized refractive error service delivery, convenience and availability and cost reduction. The possible factors influencing integration of telemedicine identified were categorized into cost, unwillingness, dominance, perception, lack of technical team, policies and network coverage. The limited human resources in the eye health ecosystem in developing countries cannot effectively deliver refractive error services to the growing population. Hence, integration of telemedicine and establishment of policies recognizing telemedicine are desirable to strengthen task shifting and scale effective refractive error coverage.

Estimation of the lost productivity to the GDP and the national cost of correcting visual impairment from refractive error in Kenya.

BACKGROUND: In developing countries such as Kenya, minimal attention has been directed towards population based studies on uncorrected refractive error (URE). However, the absence of population based studies, warrants utilization of other avenues to showcase to the stakeholders in eye health the worth of addressing URE. Hence this study estimated the lost productivity to the Gross Domestic Product (GDP) as a result of URE and the national cost required to address visual impairment from URE in Kenya. METHODS: The lost productivity to the GDP for the population aged 16-60 years was calculated. Thereafter the productivity loss of the caregivers of severe visual impaired individuals was computed as a product of the average annual productivity for each caregiver and a 5% productivity loss due to visual impairment. The productivity benefit of correcting refractive error was estimated based on the minimum wage for individuals aged between 16-60 years with URE. Estimation of the national cost of addressing URE was based on spectacle provision cost, cost of training functional clinical refractionists and the cost of establishing vision centres. A cost benefit analysis was undertaken based on the national cost estimates and a factor of 3.5 times. RESULTS: The estimated lost productivity to the GDP due to URE in in Kenya is approximately US$ 671,455,575 -US$ 1,044,486,450 annually for population aged between 16-60 years. The productivity loss of caregivers for the severe visually impaired is approximately US$ 13,882,899 annually. Approximately US$ 246,750,000 is required to provide corrective devices, US$ 413,280- US$ 108,262,300 to train clinical refractionists and US$ 39,800,000 to establish vision centres. The productivity benefit of correcting visual impairment is approximately US$ 41,126,400 annually. Finally, a cost benefit analysis showed a return of US$ 378,918,050 for human resources, US$ 863,625,000 for corrective devices and US$ 139,300,000 for establishment of vision centres. CONCLUSION: The magnitude of productivity loss due to URE in Kenya is significant warranting prioritization of refractive error services by the government and all stakeholders since any investment directed towards addressing URE has the potential to contribute a positive return.

Vision-Specific Tools for the Assessment of Health-Related Quality of Life (HR-QoL) in Children and Adolescents with Visual Impairment: A Scoping Review.

Vision-related quality-of-life (QoL) measures offer a comprehensive evaluation of the impact of eye conditions and the effectiveness of treatment on important aspects of QoL. A substantial number of tools for assessing health-related quality of life (HR-QoL) in adults have been reviewed. However, despite the high prevalence of uncorrected refractive errors causing visual impairment (VI) in children, there is a notable lack of similar tools for this vulnerable population. This review aimed to systemically map evidence on the availability and use of vision-specific instruments for assessing HR-QoL in children and adolescents with VI. This review follows the Joanna Briggs Institute (JBI) guidelines (2020) and the framework by Arksey and O'Malley and Levac et al. (2010). We conducted systematic searches through databases PubMed, Science Direct, and Scopus and search platforms Web of Science and EBSCOhost to source reviews published in English from the date of their inception to December 2023. The findings are reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews (PRISMA-ScR). We reviewed twenty tools, nine of which were developed for children in the United States and three of which were developed for children in developing countries; no tools specifically developed for children in Africa were found. In the reviewed papers, the tools were presented to children, parents, or proxies in an interview or questionnaire format. For most of the tools, reliability was assessed using internal consistency (n = 12) and test-retest reliability (n = 12). The most dominant measures of validity were construct (n = 16), content (n = 8), internal (n = 4), and criterion (n = 4). There appears to be a need for more tools developed for children in middle-low-income countries, especially for African children.

Ocular therapeutics and the profession of optometry in South Africa.

BACKGROUND:  The role of an optometrist as defined by the World Council of Optometry includes the management of ocular diseases. In 2015, the scope of optometry in South Africa was expanded to include ocular therapeutic drugs. To date approximately 27 optometrists have obtained full certification to exercise ocular therapeutic privileges. AIM:  This study aimed to determine the interest, readiness, as well as challenges, of optometrists for the inclusion of ocular therapeutics into daily practice. SETTING:  The study was set in South Africa. METHODS:  A descriptive, cross-sectional study design was employed. Convenience sampling was used to recruit 420 participants from a study population of optometrists registered with the Health Professions Council of South Africa, with data collected using an online questionnaire hosted on social media platforms and distributed by professional organisations. Data were analysed using the Statistical Package for Social Science version 27. RESULTS:  The majority of respondents (73.3%) reported keenness for ocular therapeutics certification. While 75.7% of respondents had obtained diagnostics certification, only 9.5% were registered with the Health Professions Council of South Africa (HPCSA) with ocular therapeutics certification. Most (92.1%) respondents reported the required minimum of 600 h of clinical training as a major challenge to obtaining ocular therapeutics certification. Almost all (96.9%) of the respondents agreed that ocular therapeutics certification will improve provision of optimal eyecare. CONCLUSION:  South African optometrists support and are personally interested in ocular therapeutics certification. However, while there is a preponderance of diagnostically qualified optometrists, very few are certified for ocular therapeutics with completion of the required clinical training for certification perceived as the greatest challenge.Contribution: This findings in this study highlight that, current requirements to support ocular therapeutics certification of South African optometrists should be reviewed to ensure an enabling environment for the completion of the clinical training.

Prevalence and clinical profile of keratoconus in patients presenting at a provincial hospital in KwaZulu, Natal, South Africa: A case study.

Keratoconus (KC) is a progressive, asymmetrical corneal disease, characterized by stromal thinning that leads to distortion, causing vision loss. The visual loss is secondary to corneal scarring, irregular astigmatism, and myopia. The prevalence of KC has been reported to differ in different parts of the world. The study aimed to determine the prevalence and profile of patients with KC presenting to a provincial hospital in KwaZulu-Natal, South Africa. A retrospective study design was used to review 412 clinical records of patients attending the McCord Provincial Eye Hospital (MPEH) during a five-year period (2016-2020). Data on age, race, refraction, clinical profile, treatment plan, and diagnosis were ascertained. The prevalence of KC in MPEH was found to be 13.7% with a mean age of 24.7±7.94 years. Black African and females had a higher frequency of KC compared to males and other ethnic groups. Most of the patients presented with a severe stage of KC and referral was the most common management. Central corneal thinning and Munson's sign were the most prevalent clinical signs. There was no statistically significant difference between the worse and better eye when comparing the clinical signs. The prevalence and clinical profile of patients with KC in this study was similar to that reported by previous studies and more in Blacks and females. Population based epidemiological studies are needed to determine the prevalence of KC in South Africa to enable early clinical interventions.

Motivation for postgraduate studies by nonacademic optometrists: A case study at a South African university.

Background: An increasing number of optometrists who are nonacademics are pursuing postgraduate studies, despite such qualifications traditionally being more relevant to an academic rather than a clinical setting. Aim: This study set out to explore possible reasons for the increase in postgraduate studies by nonacademic optometrists and their experiences thereof. Setting: Postgraduate optometry students who were registered at a selected South African university within the period 2010-2020 participated in the study. Methods: A descriptive cross-sectional research design was used, which entailed an online survey and a follow-up questionnaire focused on the motivation for postgraduate studies, choice of institution, research area, expectations and outcomes and supervision received. Convenience sampling was used to recruit the participants, and data were analysed with descriptive statistics. Results: Responses were received from 54 optometrists who were pursuing postgraduate studies but not currently in academia. The main reasons reported for enrolling in postgraduate studies were interest in research (69.2%) and academia (61.5%). Institutional reputation was the reason provided by 48.1% of respondents for their choice of institution for their postgraduate studies. Fifty per cent of respondents opted for research in the public health field. To be a better researcher was the most common expectation (88.5%), with 73.1% indicating achieving this outcome. Most respondents indicated that they had received constructive and timeous supervision during their studies. Conclusion: Interest in research and academia are important factors influencing nonacademic optometrists to pursue postgraduate studies; however, the postgraduate experience is likely to also facilitate development of other professional and clinical skills. Contribution: This study provides an insight into the motivation and experiences of non academic optometrists who pursue postgraduate degrees.

Vision screening as part of the school health policy in South Africa from the perspective of school health nurses.

BACKGROUND:  Vision screenings of school-going children are essential in the early detection of visual anomalies common in different age categories, which may negatively affect their academic ability and social development. Hence, their inclusion in school health policies is imperative. The aim of this study was to assess the implementation of vision screening protocols in the current Integrated School Health Screening policy of South Africa from the perspective of school health personnel. AIM:  The study sought to explore the perceptions, experiences and attitudes of the school health nurses on vision screenings included as part of the school health screenings in Gauteng province (South Africa). SETTING:  This study was located across three public healthcare facilities across Gauteng at primary healthcare levels. METHODS:  Three teams of 13 school health personnel from three primary healthcare facilities in the district of Ekurhuleni were invited to participate in the study. Focus group interviews were conducted for generating information on collective opinions and the rationale behind their views. RESULTS:  Results of the collected qualitative data revealed challenges related to training, vision screening tests, referral criteria and follow-ups or referral pathways. In addition, further challenges reported were related to communication, time, space and consent forms not signed by the parents. CONCLUSION:  Improved cohesion and communication between all role players will enable reasonable and professional provision of validated vision screening services that have the best chance of early detection of children with vision anomalies to negate possible adverse effects on their scholarly performance.

Historical Development, Applications and Advances in Materials Used in Spectacle Lenses and Contact Lenses.

Lenses used in vision correction have evolved from the initial glass reading stone of the 10th century to the currently anticipated planar metalens made from "nanopillars" of titanium dioxide. With ideas from early scientific minds being translated into reality, and military commissioned concepts adapted for civilian use, spectacle lens and contact lens materials have progressed significantly over the last century, with the expectation of further lens material innovations ahead. The purpose of this article is a review of literature on the historical developments and advances in spectacle lens and contact lens materials.

Knowledge, attitudes and practices of contact lens use in a South African adolescent population.

BACKGROUND: Contact lens usage is becoming increasingly popular amongst young people. Assessing their knowledge, attitudes and practices in relation to contact lens wear is therefore important, so that gaps in understanding or incorrect practices can be rectified to promote continued safety and success of contact lens wear. OBJECTIVES: This study aimed to assess and describe the knowledge, attitudes and practices of contact lens wearers aged 18 to 30 years, in the greater Durban area of South Africa. METHODS: A semi-structured questionnaire was used to assess the knowledge, attitudes and practice of the participants. Results: Two hundred and forty six participants completed the survey. Young contact lens wearers in this sample generally had poor knowledge with regards to appropriate hygiene and contact lens wear complications. Despite wearers exhibiting a positive attitude with satisfactory hand hygiene and lens cleaning practices, important aspects such as lens case hygiene, storage and lens removal practices were found to be unsatisfactory. Compliance with after-care visits was also unsatisfactory. CONCLUSION: There is a need for contact lens practitioners to educate young contact lens wearers regarding appropriate contact lens-related care, to promote long term ocular health and contact lens-related safety.

Visual problems: a review of prevalence studies on visual impairment in school-age children.

Childhood visual impairment (VI) have a significant impact on the educational achievement, career choices and social life of affected individual, and in children, is mainly due to either preventable or treatable causes. Reliable data on the prevalence and causes of VI in children will guide the development of a systematic vision screening program for its early detection and successful treatment of possible causes. The purpose of this literature review is to summarize the available data on prevalence and causes of VI in school-age children from various regions globally. A discussion on the major findings highlighting the definition criteria, classifications and limitations for further studies is also presented.

A review of paediatric vision screening protocols and guidelines.

Vision screening plays an important role in the early detection of children who have or probably are predisposed to have specific visual problems. The validity and reliability of the screening batteries in relation to the age group to be screened, and the person administering the test as well as the referral and follow-up criteria contribute to the overall outcome of the vision screening. Despite the long history of vision screening and significant improvement in the development of screening protocols, no agreement exists concerning the age at which children should be screened, the exact test batteries that should be included and who should conduct the screening. This review highlights some important aspects of the history of paediatric vision screening and available evidence in support of their use to detect visual conditions in children. It also examines some of the barriers against the development of paediatric vision screening models especially in low and medium income countries.

Vergence Profile and Prevalance of Non-Strabismic Vergence Anomalies Among School Children in Abia State, Nigeria.

PURPOSE: To determine the prevalence of non-strabismic vergence anomalies and their relationship with age, gender, and school level in children aged 10-16 years Method: A cross-sectional study was conducted among 537 children (255 male, 282 females; mean age 13.0 ± 2.0, years) selected from nine schools using stratified, cluster, and random sampling. The participants completed a Convergence Insufficiency Symptom Survey (CISS) and eye examinations, including the measurement of visual acuity, non-cycloplegic refraction, cover test, near point of convergence, fusional vergences, accommodative functions, and ocular health evaluation. All binocular tests were performed following the subjective refraction with the corrective lenses in place, if prescribed. RESULTS: The prevalence of low suspect, high suspect, and definite convergence insufficiency was 9.6%, 5.8%, and 4.1%, respectively. Other prevalence estimates included convergence excess (2.9%), fusional vergence dysfunction (2.6%), basic exophoria (1.7%), basic esophoria (2.8%), divergence insufficiency (0.8%), and divergence excess (0.6%). The prevalence of high suspect (p < 0.01) and definite (p < 0.01) convergence insufficiency was significantly higher in older than younger children, and as expected, in secondary more so than primary school children (p = 0.01). There was no statically significant association between gender and various vergence anomalies. CONCLUSION: The study showed that vergence anomalies are common vision conditions among Abia State school children. Given the importance of visual skills in learning and academic achievements, there is a need to develop screening and management strategies that will target those visual conditions to prevent educational and social progress being affected.

Repeatability and reproducibility of retinal nerve fibre layer thickness measurements with the iVue-100 optical coherence tomographer.

BACKGROUND: Accurate and repeatable measurements of the retinal nerve fibre layer (RNFL) thickness are important in the diagnosis and management of glaucoma and other disorders. OBJECTIVE: To assess the repeatability and reproducibility of the iVue-100 optical coherence tomographer (OCT). METHODS: The thickness of the RNFL was measured for 50 healthy participants using the iVue-100 OCT. Although both eyes per participant were measured, only right eyes were analysed here. Repeatability and reproducibility of the iVue-100 OCT were assessed using the intraclass correlation coefficient (ICC), coefficient of variation (CoV), paired t-tests and Bland-Altman analysis. RESULTS: Good intra-observer repeatability was obtained as indicated by the ICC of observer 1 (range: 0.941 - 0.976) and observer 2 (range: 0.829 - 0.953) as well by the CoV of observer 1 (range: 0.098 - 0.137) and observer 2 (0.091 - 0.132). In terms of inter-observer reproducibility, significant differences (p< 0.05) in mean measurements between the observers were noted for the average RNFL readings and in the superior and inferior quadrants as assessed with paired t-tests. Even though significant inter-session differences were found for the average RNFL thickness and the superior quadrant (p = 0.003 and p = 0.013, respectively), excellent ICCs were obtained for inter-session reproducibility (range: 0.914 - 0.979). CONCLUSION: The iVue-100 OCT demonstrated good repeatability and reproducibility for RNFL thickness measurements.

Prevalence and Causes of Visual Impairment and Blindness among Cocoa Farmers in Ghana.

PURPOSE: To determine the prevalence and causes of visual impairment and blindness among cocoa farmers in Ghana in order to formulate early intervention strategies. METHODS: A cross-sectional study using multistage random sampling from four cocoa growing districts in Ghana was conducted from November 2013 to April 2014. A total of 512 cocoa farmers aged 40 years and older were interviewed and examined. The brief interview questionnaire was administered to elicit information on the demographics and socioeconomic details of participants. The examination included assessment of visual acuity (VA), retinoscopy, subjective refraction, direct ophthalmoscopy, slit-lamp biomicroscopy and intraocular pressure (IOP). For quality assurance, a random sample of cocoa farmers were selected and re-examined independently. RESULTS: Moderate to severe visual impairment (VA <6/18 to 3/60 in the better-seeing eye) was present in 89 participants (17.4%) and 27 (5.3%) were blind (presenting VA <3/60 in the better eye) defined using presenting VA. The main causes of visual impairment were cataract (45, 38.8%), uncorrected refractive error (42, 36.2%), posterior segment disorders (15, 12.9%), and corneal opacity (11, 9.5%). CONCLUSION: The prevalence of visual impairment and blindness among cocoa farmers in Ghana is relatively high. The major causes of visual impairment and blindness are largely preventable or treatable, indicating the need for early eye care service interventions.